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Working Cover Page
Telecommunications –
Telephone Terminal Equipment Rationale and Measurement Guidelines for U.S. Network Protection
Draft 17e
August, 2006
Warning: This Document is a “work in progress” by TIA TR41.9 and as such it’s
contents may change.
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FOREWORD
This Document is a TIA Telecommunications Systems Bulletin (TSB), produced by
Working Group TR-41.9.2 under subcommittee TR-41.9 of Engineering Committee TR41, User Premises Telecommunications Requirements, under the sponsorship of the
Telecommunications Industry Association [TIA]. Telecommunications Systems Bulletins
are distinguished from TIA Standards in that TSBs contain a compilation of engineering
data or information useful to the technical community and represent approaches to good
engineering practices suggested by formulating group TR-41.9.
This Bulletin is not intended to preclude or discourage other approaches which similarly
represent good engineering practice, or which may be acceptable to, or have been
accepted by, appropriate bodies such as the Federal Communications Commission
[FCC]. Parties who wish other approaches to be considered for inclusion in future
revisions of this Bulletin are encouraged to bring them to the attention of the formulating
group. It is the intention of the formulating group to revise and update this Bulletin from
time to time as may be occasioned by changes in technology, industry practice,
government regulations, technical criteria, or other appropriate reasons.
This Document outlines test methods for the technical criteria contained in the following
documents:
CFR, Title 47, FCC Part 68
ANSI/TIA-968-A
The changes to this Document from TSB-31-B are extensive due to the restructuring of
47 CFR Part 68 and new technical criteria that have come into effect since TSB-31-B
was published. This Document supersedes TIA-TSB-31-B and represents the
consensus of the formulating group.
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TR-41.9 MEMBERS AND TSB-31-C CONTRIBUTORS
People on this list either where a voting member of TR41.9 at the time this document
was voted to publication or made contributions to the development of this document.
Organization Represented
ADTRAN, Inc
Atlinks Communications
Bourns Ltd.
Broadcom
Cisco Systems
Hewlett-Packard
Industry Canada
Industry Canada
Industry Canada
Intertek Testing Services
Littelfuse Inc.
Mitel Networks
Mobile Engineering
Paradyne Inc.
San-O-Industrial
Siemens Communication Inc.
Sprint
Thomson Inc.
Tyco Electronics
Underwriters Labs
Underwriters Labs
Verizon
Vtech Engineering
Name of Representative
Bell, Larry
Pinkham, Clint
Maytum, Michael
Rahamim, Rafi
Lawler, Tim
Roleson, Scott
Guevara, Efrain
Mulvihill, Matthew
Dawood, Hazim
Flom, Gary
Havens, Philip
Slingerland, Greg
Bipes, John
Walsh, Peter
Lindquist, Carl
Tung, Tailey
Chamney, Cliff
Hunt, Roger
Martin,Al
Ivans, Randy
Nguyen, Anh
Bishop, Trone
Whitesell, Steve
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CONTENTS
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FOREWORD
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TR-41.9 MEMBERS AND TSB-31-C CONTRIBUTORS .................................................................................... II
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CONTENTS
5
LIST OF FIGURES .............................................................................................................................................VII
6
1
INTRODUCTION..................................................................................................................... 10
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2
SCOPE .................................................................................................................................... 11
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3
REFERENCES ........................................................................................................................ 12
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DEFINITIONS, ACRONYMS AND ABBREVIATIONS........................................................... 13
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GENERAL INFORMATION .................................................................................................... 21
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LEAKAGE CURRENT LIMITATIONS (ANALOG AND DIGITAL) ANSI/TIA-968-A, 4.3 ....... 49
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HAZARDOUS VOLTAGE LIMITATIONS ANSI/TIA-968-A, 4.4............................................. 54
.................................................................................................................................................... I
.................................................................................................................................................. III
5.1
Safety Warning About The Procedures In This Document......................................21
5.2
General Document Structure ..................................................................................21
5.3
Simulator Circuit Theory .........................................................................................21
5.4
Test Conditions .......................................................................................................22
5.5
Suggested Equipment List (SEL) ............................................................................22
5.6
Test Requirements Matrix .......................................................................................29
ENVIRONMENTAL SIMULATION ANSI/TIA-968-A, 4.2 ....................................................... 30
6.1
Sequencing of Environmental Simulations..............................................................30
6.2
Mechanical Shock ANSI/TIA-968-A, 4.2.1 .............................................................35
6.3
Telephone Line Surge - Type A, Metallic. ANSI/TIA-968-A, 4.2.2.1 ......................36
6.4
Telephone Line Surge - Type A, Longitudinal. ANSI/TIA-968-A, 4.2.2.2................38
6.5
Telephone Line Surge - Type B, Metallic. ANSI/TIA-968-A, 4.2.3.1 ......................40
6.6
Telephone Line Surge - Type B, Longitudinal. ANSI/TIA-968-A, 4.2.3.2.................44
6.7
Power Line Surge ANSI/TIA-968-A, 4.2.4 ..............................................................47
8.1
Hazardous Voltage Limitations, General ANSI/TIA-968-A, 4.4.1 ...........................54
8.2
Hazardous Voltage Limitations, E&M ANSI/TIA-968-A, 4.4.1.1, 4.4.1.2, 4.4.1.3...56
8.3
Hazardous Voltage Limitations, OPS ANSI/TIA-968-A, 4.4.1.4 .............................62
8.4
Hazardous Voltage Limitations, DID ANSI/TIA-968-A, 4.4.1.5 ...............................65
8.5
Hazardous Voltage Limitations, LADC ANSI/TIA-968-A, 4.4.1.6 ...........................67
8.6
Ringdown Voiceband Private Line and Metallic Channel Interface .............................
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ANSI/TIA-968-A, 4.4.1.7 .........................................................................................70
8.7
Physical Separation of Leads ANSI/TIA-968-A, 4.4.2 .............................................73
8.8
Ringing Sources ANSI/TIA-968-A, 4.4.4 ................................................................75
8.9
Intentional Operational Paths to Ground ANSI/TIA-968-A, 4.4.5.1.........................81
8.10
Intentional Protective Paths to Ground ANSI/TIA-968-A, 4.4.5.2 ...........................84
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SIGNAL POWER LIMITATIONS ANSI/TIA-968-A, 4.5 .......................................................... 87
9.1
Voiceband Signal Power – Not Network Control signals
ANSI/TIA-968-A, 4.5.2.1.1 ......................................................................................87
9.2
Voiceband Signal Power - Network Control Signals
ANSI/TIA-968-A, 4.5.2.1.2 ......................................................................................96
9.3
Through-Transmission Equipment – DC Conditions for On-Premises
ANSI/TIA-968-A, 4.5.2.3.1 ....................................................................................102
9.4
Through-Transmission Equipment – Data ANSI/TIA-968-A 4.5.2.3.2 ................105
9.5
Voiceband Signal Power - Data ANSI/TIA-968-A, 4.5.2.4....................................107
9.6
Through-Transmission – Port to Port Amplification ANSI/TIA-968-A, 4.5.2.5.1....111
9.7
Through-Transmission - SF Cutoff ANSI/TIA-968-A, 4.5.2.5.1(7) .......................117
9.8
Through-Transmission - SF/Guard Bands ANSI/TIA-968-A, 4.5.2.5.2 .................120
9.9
Return Loss, Tie Trunk - Two Wire ANSI/TIA-968-A, 4.5.2.6.1 ............................126
9.10
Return Loss, Tie Trunk - Four Wire ANSI/TIA-968-A, 4.5.2.6.2 ...........................129
9.11
Transducer Loss, Tie Trunk - Four Wire ANSI/TIA-968-A, 4.5.2.6.3 ....................133
9.12
DC Conditions, OPS ANSI/TIA-968-A, 4.5.2.7.....................................................137
9.13
Signal Power 3995 Hz - 4005 Hz – Not Network Control Signals
ANSI/TIA-968-A, 4.5.3.1 .......................................................................................140
9.14
Through Transmission – 3995-4005 Hz vs 600-4000 Hz
ANSI/TIA-968-A, 4.5.3.2 .......................................................................................144
9.15
Non-LADC Longitudinal Voltage – 0.1 - 4 kHz ANSI/TIA-968-A, 4.5.4 .................149
9.16
Non-LADC Metallic Voltage - 4 kHz to 30 MHz ANSI/TIA-968-A, 4.5.5.1 .............154
9.17
Non-LADC Longitudinal Voltage - 4 kHz to 6 MHz ANSI/TIA-968-A, 4.5.5.2 ........163
9.18
Metallic Voltage - 0.01 kHz to 30 MHz, LADC ANSI/TIA-968-A, 4.5.6.1, 4.5.6.2 .173
9.19
Longitudinal Voltage - 0.01 kHz to 6 MHz, LADC ANSI/TIA-968-A, 4.5.6.3 .........185
9.20
Pulse Repetition Rate, Subrate/PSDS, ANSI/TIA-968-A, 4.5.8.1.1 and 4.5.8.3.1 .196
9.21
Encoded Analog Content ANSI/TIA-968-A 4.5.8.1.2, 4.5.8.4, 4.5.8.2.5, 4.5.10 ..199
9.22
Equivalent PSD For Maximum Output, Subrate – ANSI/TIA-968-A, 4.5.8.1.3 ......203
9.23
Average Power, Subrate, Non-Secondary Channel Rates, Secondary Channel
Rates ANSI/TIA-968-A, 4.5.8.1.4 and 4.5.8.1.5 ...................................................206
9.24
Pulse Template, Subrate/PSDS ANSI/TIA-968-A, 4.5.8.1.6 and 4.5.8.3.2............209
9.25
Average Power, Subrate ANSI/TIA-968-A, 4.5.8.1.7 ...........................................212
9.26
Pulse Repetition Rate, 1.544
Mb/s ANSI/TIA-968-A, 4.5.8.2.1 .................................................
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Pulse Template, 1.544 Mb/s ANSI/TIA-968-A, 4.5.8.2.2, 4.5.8.2.3 .......................217
9.28
Output Power, 1.544 Mb/s ANSI/TIA-968-A, 4.5.8.2.4 .........................................220
9.29
Unequipped Sub-rate Channels ANSI/TIA-968-A, 4.5.8.2.6 .................................224
9.30
Conditioning ADSL EUT to Transmit Continuously ...............................................226
9.31
Total Average Power, ADSL Terminal Equipment
ANSI/TIA-968-A-3, 4.5.9.1.1 .................................................................................228
9.32
Power Spectral Density, ADSL Terminal Equipment ANSI/TIA-968-A-3, 4.5.9.1.2,
4.5.9.1.3................................................................................................................231
9.33
Longitudinal Output Voltage, ADSL Terminal Equipment
ANSI/TIA-968-A-3, 4.5.9.1.4 ................................................................................244
9.34
Voiceband Signal Power - Non-approved external signal sources
ANSI/TIA-968-A-3, 4.5.2.2 ....................................................................................248
TRANSVERSE BALANCE LIMITATIONS ANSI/TIA-968-A, 4.6 ........................................ 253
10.1
Transverse Balance, Analog ANSI/TIA-968-A, 4.6.2 ...........................................253
10.2
Transverse Balance, Digital ANSI/TIA-968-A, 4.6.3, 4.6.4 ...................................259
ON HOOK IMPEDANCE LIMITATIONS ANSI/TIA-968-A, 4.7 ............................................ 264
11.1
DC Resistance ANSI/TIA-968-A, 4.7.2.1, 4.7.2.2.................................................264
11.2
DC Current During Ringing, Loop Start and Ground Start
ANSI/TIA-968-A, 4.7.2.3, 4.7.3.1 ..........................................................................269
11.3
AC Impedance During Ringing, Loop Start and Ground Start (Metallic and
Longitudinal) ANSI/TIA-968-A, 4.7.2.4, 4.7.2.5, 4.7.3.2 ........................................273
11.4
REN Calculation ANSI/TIA-968-A, 4.7.4, 4.7.5 .....................................................278
11.5
OPS Ring Trip, PBX with DID ANSI/TIA-968-A, 4.7.6..........................................280
11.6
Transitioning to the Off-Hook State and Make-busy ANSI/TIA-968-A, 4.7.8 ........283
11.7
Manual Programming of Repertory Numbers, ANSI/TIA-968-A, 4.7.8.1 ...............285
11.8
Automatic Stuttered Dial Tone Detection ANSI/TIA-968-A, 4.7.8.2.......................287
BILLING PROTECTION ANSI/TIA-968-A, 4.8 ..................................................................... 290
12.1
Call Duration for Data Equipment, Protective Circuitry ANSI/TIA-968-A, 4.8.1.1 ..290
12.2
Call Duration for Data Applications, Terminal Equipment ANSI/TIA-968-A, 4.8.1.2294
12.3
On-hook Signal Power, Analog ANSI/TIA-968-A, 4.8.2 .......................................298
12.4
Off-Hook Loop Current ANSI/TIA-968-A, 4.8.3 ....................................................302
12.5
Signaling Interference, Analog ANSI/TIA-968-A, 4.8.4.1......................................308
12.6
Signaling Interference, Digital ANSI/TIA-968-A, 4.8.4.2 .......................................312
12.7
On-Hook Signal Power, Subrate and 1.544 Mb/s ANSI/TIA-968-A, 4.8.5 ............316
12.8
Signaling Duration, 1.544 Mb/s ANSI/TIA-968-A, 4.8.6........................................320
12.9
Operating Requirements for DID ANSI/TIA-968-A, 4.8.7 ....................................323
CONNECTORS..................................................................................................................... 327
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Gold Contact Interface ..........................................................................................327
13.2
Non-gold Contact Interface ...................................................................................327
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APPENDIX A, TEMPLATES FOR DIGITAL PULSES .................................................................................... 367
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APPENDIX B, EXAMPLE CALCULATIONS OF WAVEFORM ENERGY LEVELS....................................... 385
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APPENDIX C, ALTERNATE TRANSVERSE BALANCE, DIGITAL EUT ....................................................... 387
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APPENDIX D, TEST PROCEDURES FOR PASSIVE SPLITTER FILTERS AND PASSIVE MICRO-FILTERS391
OTHER TYPES OF DSL TERMINAL EQUIPMENT ............................................................ 328
14.1
Metallic Signals TIA-968-A-3, 4.5.9.2.1 and TIA-968-A-4, 4.5.9.2.4......................328
14.2
Longitudinal Output Voltage Limits TIA-968-A-3 and TIA-968-A-4, 4.5.9.2.3 ........334
14.3
Transverse Balance TIA-968-A-3, 4.6.5................................................................337
HEARING AID COMPATIBILITY .......................................................................................... 339
15.1
Hearing Aid Compatibility – Magnetic Field Intensity 47 CFR, 68.316 .................339
15.2
Hearing Aid Compatibility - Volume Control 47 CFR, 68.317 ................................347
MISCELLANEOUS................................................................................................................ 355
16.1
Limitations on Automatic Redialing 47 CFR, 68.318(b) ........................................355
16.2
Line Seizure by Automatic Telephone Dialing Systems - 47 CFR, 68.318(c) .......360
16.3
Telephone Facsimile Machines: Identification of the Sender of Messages
(FAX branding) – 47 CFR, 68.318(d) ....................................................................362
16.4
Equal Access to Common Carriers - 47 CFR, 68.318(e) ......................................365
A.1
Templates for Subrate and PSDS Digital Pulses ..................................................367
A.2
Templates for ISDN PRA and 1.544 Mb/s Digital Pulses ......................................382
A.3
Background ..........................................................................................................387
A.4
Purpose ................................................................................................................388
A.5
Equipment ............................................................................................................388
A.6
Equipment States Subject To Test .......................................................................388
A.7
Procedure .............................................................................................................388
D.1
Background ..........................................................................................................391
D.2
Example of Splitter Filter .......................................................................................391
D.3
Example of Micro-Filter .........................................................................................392
D.4
Applicable ANSI/TIA-968-A Technical Criteria from TSB-31-C Test Matrix ..........392
D.5
Test Methods for Splitter Filters ............................................................................395
D.6
Test Methods for Micro-Filters ..............................................................................397
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LIST OF FIGURES
Figure 6.1-1 Environmental Flowchart ................................................................................................... 32
Figure 7-1. Leakage Current..................................................................................................................... 53
Figure 8.2-1 E or M-Lead Contact Protection ........................................................................................ 61
Figure 8.8-1 Ringing Sources, Two-Wire ............................................................................................... 78
Figure 8.8-2 Ringing Sources, Four-Wire ............................................................................................. 79
Figure 8.8-3 Ringing Protection .............................................................................................................. 80
Figure 8.9-1 Intentional Operational Paths to ground .......................................................................... 83
Figure 8.10-1 Intentional Protective Paths to Ground .......................................................................... 86
Figure 9.1-1. Voiceband Signal Power, Two-Wire ................................................................................. 93
Figure 9.1-2. Voiceband Signal Power, Four-Wire ................................................................................ 94
Figure 9.1-3. Voiceband Signal Power, E&M Tie ................................................................................... 95
Figure 9.2-1. Network Control Signal Power, Two-Wire ..................................................................... 100
Figure 9.2-2. Network Control Signal Power, Four-Wire .................................................................... 101
Figure 9.3-1. DC Conditions for Through Transmission .................................................................... 104
Figure 9.5-1. Voiceband Signal Power, Data, TE ................................................................................ 110
Figure 9.6-1 Through Transmission, Analog....................................................................................... 114
Figure 9.6-2. Through Transmission, Digital ....................................................................................... 115
Figure 9.6-3. Digital EUT Arrangement for Figure 9.6-2 ..................................................................... 116
Figure 9.7-1. Single Frequency Cut-off ................................................................................................ 119
Figure 9.8-1. Through Transmission - SF Guard Bands, Analog ...................................................... 123
Figure 9.8-2. Through Transmission - SF Guard Bands, Digital ....................................................... 124
Figure 9.8-3. Digital EUT Arrangement for Figure 9.8-2 ..................................................................... 125
Figure 9.9-1. Return Loss, Two-Wire .................................................................................................... 128
Figure 9.10-1. Return Loss, Four-Wire, T&R ....................................................................................... 131
Figure 9.10-2. Return Loss, Four-Wire, T1&R1 .................................................................................. 132
Figure 9.11-1. Transducer Loss, Forward............................................................................................ 135
Figure 9.11-2 Transducer Loss, Reverse ............................................................................................. 136
Figure 9.12-1. OPS DC Conditions ....................................................................................................... 139
Figure 9.13-1. Signal Power, 3995-4005 Hz, Internal Sources ........................................................... 143
Figure 9.14-1 Signal Power, 3995-4005 Hz vs 600-4000 Hz, Through Transmission ...................... 148
Figure 9.15-1. Voiceband Longitudinal Voltage .................................................................................. 153
Figure 9.16-1. Non-LADC Metallic 4 kHz to 30 MHz ............................................................................ 161
Figure 9.16-2. Non-LADC Metallic 270 kHz to 30 MHz ........................................................................ 162
Figure 9.17-1. Non-LADC Longitudinal 4 kHz to 6 MHz ...................................................................... 171
Figure 9.17-2. Non-LADC Longitudinal 270 kHz to 6 MHz .................................................................. 172
Figure 9.18-1. LADC Metallic 10 Hz to 4 kHz, T&R .............................................................................. 179
Figure 9.18-2. LADC Metallic 10 Hz to 4 kHz, T1 & R1 ........................................................................ 180
Figure 9.18-3. LADC Metallic 700 Hz to 270 kHz, T&R ........................................................................ 181
Figure 9.18-4. LADC Metallic 700 Hz to 270 kHz, T1&R1 ..................................................................... 182
Figure 9.18-5. LADC Metallic 270 kHz to 30 Mhz, T&R ....................................................................... 183
Figure 9.18-6. LADC Metallic 270 kHz to 30 MHz, T1&R1 ................................................................... 184
Figure 9.19-1. LADC Longitudinal 10 Hz - 4 kHz, T&R ........................................................................ 190
Figure 9.19-2. LADC Longitudinal 10 Hz to 4 kHz, T1 & R1 ............................................................... 191
Figure 9.19-3. LADC Longitudinal 4 kHz to 270 kHz, T & R ............................................................... 192
Figure 9.19-4. LADC Longitudinal 4 kHz to 270 kHz, T1 & R1 ........................................................... 193
Figure 9.19-5. LADC Longitudinal 270 kHz to 6 MHz, T & R .............................................................. 194
Figure 9.19-6. LADC Longitudinal 270 kHz to 6 Mhz, T1 & R1 ........................................................... 195
Figure 9.20-1. Subrate, Pulse Repetition Rate ..................................................................................... 198
Figure 9.21-1. Encoded Analog Content .............................................................................................. 202
Figure 9.22-1. Subrate Signal Power ..................................................................................................... 205
Figure 9.23-1. Subrate Signal Power .................................................................................................... 208
Figure 9.24-1. Subrate and PSDS, Pulse Template. ............................................................................ 211
Figure 9.25-1. Subrate, Average Power ............................................................................................... 214
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Figure 9.26-1. 1.544 megabits per second (Mb/s), Pulse Repetition Rate ......................................... 216
Figure 9.27-1. 1.544 Mb/s, Pulse Template connection diagram ........................................................ 219
Figure 9.28-1. 1.544 megabits per second (Mb/s), Output Power ...................................................... 223
Figure 9.31-1. Average Signal Power .................................................................................................... 229
Figure 9.32-1. PSD Connection Diagram For Segments 1 & 2 ........................................................... 237
Figure 9.32-2. Sample PSD Plot For Segment 1 ................................................................................... 238
Figure 9.32-3. Sample PSD Plot For Segment 2 ................................................................................... 239
Figure 9.32-4. PSD Connection Diagram For Segment 3 .................................................................... 240
Figure 9.32-5. Sample PSD Plot For Segment 3 ................................................................................... 241
Figure 9.32-6. PSD Connection Diagram For Segment 4 .................................................................... 242
Figure 9.32-7. Sample PSD Plot For Segment 4 ................................................................................... 243
Figure 9.33-1. LOV Test Fixture & Connection Diagram ..................................................................... 246
Figure 9.33-2. Sample LOV Plot ............................................................................................................. 246
Figure 9.36-1. Voiceband Signal Power - Non-approved external signal sources ......................... 252
Figure 10.1-1 Transverse Balance, Analog.......................................................................................... 258
Figure 10.2-1 Transverse Balance, Digital ........................................................................................... 263
Figure 11.1-1. DC Resistance, T-R ....................................................................................................... 267
Figure 11.1-2. DC Resistance, T-GND & R-GND ................................................................................. 268
Figure 11.2-1. DC Current During Ringing .......................................................................................... 272
Figure 11.3-1. AC Impedance, T-R ....................................................................................................... 276
Figure 11.3-2. AC Impedance, T-GND & R-GND ................................................................................. 277
Figure 11.5-1. OPS Ring Trip................................................................................................................ 282
Figure 11.7-1. Manual Programming of Repertory Dialing Numbers ............................................... 286
Figure 11.8-1. Manual Programming of Repertory Dialing Numbers ............................................... 289
Figure 12.1-1. Call Duration, PC, Transmit .......................................................................................... 292
Figure 12.1-2. Call Duration, PC, Receive ............................................................................................ 293
Figure 12.2-1. Call Duration, EUT, Transmit ........................................................................................ 296
Figure 12.2-2. Call Duration, EUT, Receive.......................................................................................... 297
Figure 12.3-1. On-hook Signal Power, TE ............................................................................................ 300
Figure 12.3-2. On-hook Signal Power, PC ........................................................................................... 301
Figure 12.4-1. Loop Current, 200 ohm Method.................................................................................... 306
Figure 12.4-2. Loop Current, 25% Method ........................................................................................... 307
Figure 12.5-1. Signaling Interference .................................................................................................... 311
Figure 12.6-1. 1.544 Mb/s, Signaling Interference ............................................................................... 315
Figure 12.7-1. Subrate and 1.544 Mb/s, On-hook Level...................................................................... 319
Figure 12.8-1. 1.544 megabits per second (Mb/s), Signaling Duration ............................................. 322
Figure 12.9.5.1-1. Analog Direct Inward Dialing .................................................................................. 325
Figure 12.9.5.2-1 1.544 megabits per second (Mb/s) Direct Inward Dialing ...................................... 326
Figure 14.1-1 Test Configuration to Establish Data Mode .................................................................. 333
Figure 14.1-2 Test Configuration to Measure PSD and Total Power ................................................. 333
Figure 14.2-1 LOV TEST FIXTURE & CONNECTION DIAGRAM ......................................................... 336
Figure 15.1-1 Setup for testing 47 CFR, 68.316 HAC for Analog Telephone ................................... 343
Figure 15.1-2 Setup for testing 47 CFR, 68.316 HAC for ISDN Telephone ...................................... 344
Figure 15.1-3 Setup for testing 47 CFR, 68.316 HAC for Proprietary & Special use Telephone ... 345
Figure 15.1-4 Setup for testing 47 CFR, 68.316 HAC for IP-based Telephone ................................ 346
Figure 15.2-1 Setup for testing 47 CFR, 68.317 HAC volume control for Analog Telephone ........ 351
Figure 15.2-2 Setup for testing 47 CFR, 68.317 HAC volume control for ISDN Telephone ........... 352
Figure 15.2-3 Setup for testing 47 CFR, 68.317 HAC volume control for
Proprietary & Special use Telephone ............................................................................................ 353
Figure 15.2-4 Setup for testing 47 CFR, 68.317 HAC volume control for IP-based Telephone ..... 354
Figure 16.1-1 Limitations on automatic redialing ............................................................................... 359
Figure A1-1. Subrate, Pulse Template, 2.4 kilobits per second (kb/s) .............................................. 368
Figure A1-2. Subrate, Pulse Template, 3.2 kilobits per second (kb/s) .............................................. 369
Figure A1-3. Subrate, Pulse Template, 4.8 kilobits per second (kb/s) .............................................. 370
Figure A1-4. Subrate, Pulse Template, 6.4 kilobits per second (kb/s) .............................................. 371
Figure A1-5. Subrate, Pulse Template, 9.6 kilobits per second (kb/s) .............................................. 372
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Figure A1-6. Subrate, Pulse Template, 12.8 kilobits per second (kb/s) ............................................ 373
Figure A1-7. Subrate, Pulse Template, 19.2 kilobits per second (kb/s) ............................................ 374
Figure A1-8. Subrate, Pulse Template, 25.6 kilobits per second (kb/s) ............................................ 375
Figure A1-9. Subrate, Pulse Template, 38.4 kilobits per second (kb/s) ............................................ 376
Figure A1-10. Subrate, Pulse Template, 51.2 kilobits per second (kb/s) .......................................... 377
Figure A1-11. Subrate, Pulse Template, 56.0 kilobits per second (kb/s) .......................................... 378
Figure A1-12. Subrate, Pulse Template, 72.0 kilobits per second (kb/s) .......................................... 379
Figure A1-13. PSDS Type II Pulse Template, 144 kilobits per second (kb/s) .................................. 380
Figure A1-14. PSDS Type Iii Pulse Template, 160 kilobits per second (kb/s) .................................. 381
Figure A2-1. 1.544 megabits per second (Mbps), Pulse Template, Option B ................................... 383
Figure A2-2. 1.544 megabits per second (Mbps), Pulse Template, Option C ................................... 384
Figure B1-1. Calculation of Energy Levels .......................................................................................... 386
Figure C-1: Test Fixture To Measure Transverse Balance Using A Ratio Of Currents ................... 390
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1 INTRODUCTION
47 CFR Part 68 of the Federal Communications Commission (FCC) rules and
regulations (Clause 3, ref 9) contains and references the minimum technical standards
that terminal equipment must meet in order to be connected to the telephone network.
47 CFR Part 68 references technical criteria adopted by the Administrative Council for
Terminal Attachments (ACTA) which provides uniform standards for the protection of
the telephone network from harm caused by the connection of terminal equipment. 47
CFR Part 68 defines harm as:
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electrical hazards to the personnel of providers of wireline telecommunications;
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damage to the equipment of providers of wireline telecommunications;
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malfunction of the billing equipment of providers of wireline telecommunications; and,
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
degradation of service to persons other than the user of the subject terminal
equipment and his calling or called party.
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In addition, 47 CFR Part 68 contains terminal equipment requirements that address
specific consumer protection issues. At the time of publication these were:

compatibility with magnetically coupled hearing aids;
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receive volume control on devices with a handset or headset;
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identification of the sender of the message by telephone facsimile machines;
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access to common carriers;
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automatic dialing and redialing capability; and,
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
line seizure by automatic telephone dialing systems.
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Terminal equipment may not be connected to the telephone network unless it has either
been certified by a Telecommunication Certification Body (TCB) or the responsible party
has followed all of the procedures in 47 CFR Part 68 for a Supplier’s Declaration of
Conformity (SDoC). Both of these approval processes require terminal equipment to be
tested for compliance with the technical criteria in 47 CFR Part 68 and the technical
criteria adopted by the ACTA. This Document recommends test procedures, test
equipment, and guidelines for determining compliance with the technical criteria in 47
CFR Part 68 and the technical criteria adopted by the ACTA.
The ACTA can be contacted via the Internet at www.part68.org.
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SCOPE
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This Document proposes at least one measurement procedure for each technical
requirement and, in some cases, an alternative measurement procedure. However, in
most cases, these proposed procedures are not exclusive. Other measurement
procedures and test equipment may provide equivalent results.
This Document recommends test procedures, test equipment, and guidelines for
determining compliance with the technical requirements of 47 CFR Part 68 and the
technical criteria adopted by the ACTA. At the time of publication, this
Telecommunications Systems Bulletin [TSB] addressed requirements in the following
Documents:
CFR, Title 47, FCC Part 68
ANSI/TIA-968-A
ANSI/TIA-968-A-1 (addendum)
ANSI/TIA-968-A-2 (addendum)
ANSI/TIA-968-A-3 (addendum)
ANSI/TIA-968-A-4 (addendum)
In the event of conflict between any of the standards outlined above and this Document,
the standard takes precedence.
The test procedures do not cover the administrative or other equipment authorization
procedures that may be required to obtain product approval. It is recommended that
you refer to the administrative requirements outlined by the ACTA. TIA also has TIATSB-129-A that summarizes these administrative requirements.
Each test procedure is cross-referenced to the appropriate subclause of the applicable
requirements document. subclause 5.6 provides a test requirement matrix that indicates
the applicable requirement(s) and test guideline(s) for each specific type of network
interface.
Some of the tests or procedures specified in this Document may involve the presence of
hazardous voltages and currents or other potential dangers. Some of these hazards
have been identified, and appropriate warnings have been included in the text
specifying such tests or procedures. Appropriate safety precautions are always
recommended when performing any laboratory test or procedure.
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3
REFERENCES
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2. ANSI/TIA-470-A, Telephone Instruments with Loop Signaling
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3. ANSI/TIA-470.110-C, Telecommunications – Telephone Terminal Equipment –
Handset Acoustic Performance Requirements for Analog Terminals
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4. ANSI/TIA-579, Acoustic-to-Digital and Digital-to-Acoustic Transmission Requirements
for ISDN Terminals.
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5. ANSI/TIAEIA-810-A -2000, Telecommunications – Telephone Terminal Equipment –
Transmission Requirements for Narrowband Voice Over IP and Voice Over PCM
Digital Wireline Telephones.
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6. ANSI/TIA-968-A (2002), Telecommunications – Telephone Terminal Equipment Technical Requirements for Connection of Terminal Equipment to the Telephone
Network
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7. ANSI/TIA-968-A-1 (2003), Telecommunications – Telephone Terminal Equipment Technical Requirements for Connection of Terminal Equipment to the Telephone
Network
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8. ANSI/TIA-968-A-2 (2004), Telecommunications – Telephone Terminal Equipment Technical Requirements for Connection of Terminal Equipment to the Telephone
Network
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9. ANSI/TIA-968-A-3 (2005), Telecommunications – Telephone Terminal Equipment Technical Requirements for Connection of Terminal Equipment to the Telephone
Network
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10. ANSI/TIA-968-A-4 (2006), Telecommunications – Telephone Terminal Equipment Technical Requirements for Connection of Terminal Equipment to the Telephone
Network
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11. ANSI S1.15-1997 (R2001), Measurement Microphones – Part 1: Specification for
Laboratory Standard Microphones
The following documents contain provisions that may be useful in carrying out the
recommended test procedures and guidelines for determining compliance provided in
this document. At the time of publication, the editions indicated were valid. All
documents are subject to revision, and parties to agreements based on this Document
are encouraged to investigate the possibility of applying the most recent editions of the
documents published by them.
1. ANSI T1.401-2000, Network to Customer Installation Interfaces – Analog Voice grade
Switched Access Lines Using Loop-Start and Ground-Start Signaling
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12. ANSI S3.7-1995 (R2003), Method for Coupler Calibration of Earphones.
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13. CS-03, (Issue 9, November 2004, Industry Canada), Compliance Specification for
Terminal Equipment, Terminal Systems, Network Protection Devices, Connection
Arrangements and Hearing Aids Compatibility.
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14. FCC Part 2, Code of Federal Regulations (CFR), Title 47, Part 2, Frequency
Allocations and Radio Treaty Matters; General Rules and Regulations.
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15. FCC Part 68, Code of Federal Regulations (CFR), Title 47, Part 68, Connection of
Terminal Equipment to the Telephone Network.
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16. IEEE 269-2002, IEEE Standard Methods for Measuring Transmission Performance of
Analog and Digital Telephone Sets, Handsets, and Headsets.
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17. IEEE 661-1979 (R1998), IEEE Standard Method for Determining Objective Loudness
Ratings of Telephone Connections.
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18. IEEE 1027 (1996), Method for Measuring of the Magnetic Field Intensity In The
Vicinity of a Telephone Receiver.
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19. TIA-504 (1995)(R2003), Telecommunications-Telephone Terminal EquipmentMagnetic Field and Acoustic Gain Requirements for Headset Telephones Intended for
Use by the Hard of Hearing.
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20. ITU-T Recommendation K.21 (2003-07) Resistibility of telecommunication equipment
installed in customer premises to overvoltages and overcurrents
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21. ITU-T P.57 (11/2005), Series P: Telephone Transmission Quality, Telephone
Installations, Local Line Networks – Objective Measuring Apparatus – Artificial Ears.
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22. ITU-T P.79 (09/1999), Series P: Telephone Transmission Quality, Telephone
Installations, Local Line Networks – Measurements Related to Speech loudness –
Calculation of Loudness Ratings for Telephone Sets.TIA/TSB-129-A (2002),
Telecommunications – Telephone Terminal Equipment - U.S. Network Connections
Regulatory Approval Guide
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23. TIA/TSB-168-A (2003), Telecommunications – Telephone Terminal Equipment –
Labeling Requirements
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24. TIA-470.000-C (2004), Telecommunications Terminal Equipment Overview of
Performance Standards for Analog Telephones.
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4
DEFINITIONS, ACRONYMS AND ABBREVIATIONS
For the purposes of this Document, the following definitions apply
ADSL: Asynchronous Digital Subscriber Loop
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Cadenced Ringing: The process of alerting the called party with the application of a
ringing signal which is cycled on and off.
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Capture Level: Equipment with AGC (Automatic Gain Control) signal power limiting
has virtually no output signal power for input levels below a certain value. At some input
signal power, the output level will become significant (usually corresponding to the
expected output level for service application). The input level at which this occurs is
defined as the “capture level”.
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Central office implemented telephone: A telephone executing coin acceptance
requiring coin service signaling from the central office on a loop start access line.
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followed by a 4-second quiet interval. This sequence is repeated until the called party answers
or the call is abandoned.
Note: For 47 CFR Part 68 and ANSI/TIA-968-A testing purposes, central office implemented
telephones are treated somewhat differently than most loop start devices due to the use of coin
service signaling. The differences are identified by notes and explanatory text throughout this
Document. See also the definition for coin-implemented telephone.
CO: Telephone Central Office.
CODEC: Coder/Decoder (analog or digital)
Coin-implemented telephone: A telephone containing all circuitry required to execute
coin acceptance and related functions within the instrument itself and not requiring coin
service signaling from the central office.
Note: For 47 CFR Part 68 and ANSI/TIA-968-A testing purposes, coin-implemented telephones are
treated like any other loop start device. See also the definition for central office implemented
telephone.
Common Mode: See Longitudinal Mode.
CPE [Customer Premises Equipment]: Equipment which is located on the customer's
side of the network interface.
DC Signal: A DC voltage or current.
DC Signaling: The transmission of information using changes in DC signals.
Note: Pulse dialing is an example of DC signaling used for the purpose of network addressing.
dBm: Power level in decibels with reference to a power of 0.001 W (e.g., 0 dBm is a
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power level of 1 mW).
dBV: Voltage in decibels with reference to a voltage level of 1 V (e.g. 0 dBV is a
voltage level of 1 V).
DID [Direct Inward Dialing]: A feature that permits incoming PSTN calls to be routed
directly to a PBX station upon receipt of addressing information.
Differential Mode: See Metallic Mode.
DTMF [Dual Tone Multi-Frequency]: A means of network signaling that uses a
simultaneous combination of two specified voiceband tones to represent a digit (i.e.
twelve different combinations of seven tones provide digits 0 through 9, *, and #).
Encoded Analog Content: The digital representation of analog signals encoded in a
digital bitstream. See also Section 13.10.1.
EUT: Equipment Under Test.
FIC: Facility Interface Code
A code which identifies the type of network facility necessary for a connection.
Note: These codes are listed in TSB-129-A.
Ground Start: A method of signaling whereby one of the network connections is
grounded by equipment (CO or CPE) originating a demand for service.
Intentional Conducting Path to Ground: Any electrical path which, by design, has
components which are intended to allow currents to flow to ground.
ISDN: Integrated Services Digital Network
ISDN BRA: Basic Rate Access
ISDN Basic Rate Interface: A two-wire interface between the terminal equipment and
ISDN BRA
ISDN PRA: Primary Rate Access
ISDN Primary Rate Interface: A four-wire interface between the terminal equipment
and 1.544 Mbps PRA.
Isolated Pulse: A pulse whose waveform is unaffected by leading or trailing pulses.
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KTS: Key Telephone System
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Off-Hook: A term used to denote the active state of telephone terminal equipment.
LADC [Local Area Data Channel]: A channel which allows wider than voiceband
frequency transmission over network private line metallic facilities.
LAN: Local Area Network
Live Voice: Actual human speech as opposed to recorded or synthesized speech.
Longitudinal Mode: That portion of a signal, which is identical in amplitude and phase,
on both leads of a transmission pair with respect to ground.
Loop Start: A method of signaling using the completion of a DC current path (loop).
Metallic Mode: That portion of a signal, which is identical in amplitude and opposite in
phase, on both leads of a transmission pair with respect to ground.
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On-Hook: A term used to denote the inactive state of telephone terminal equipment.
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OPS [Off Premises Station]: CPE intended to be located on a premises not
contiguous with the premises of its associated PBX, or KTS, and where the two units
are connected via telephone network facilities.
Overload Point: For signal power limiting circuits incorporating automatic gain control
method, the “overload point” is the value of the input signal that is 15 dB greater than
the capture level.
For signal power limiting circuits incorporating peak limiting method, the “overload point”
is defined as the input level at which the equipment’s through gain decreases by 0.4 dB
from its nominal constant gain.
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PBX: Private Branch Exchange
PC: Protective Circuitry.
Primary Protector: Devices, installed by the telephone companies, on circuits which
are exposed to voltages induced on cables by lightning strikes.
Note: Such devices limit the magnitude of the voltage presented to the customer premises wire and
equipment.
PSD: Power Spectral Density
PSDS Type II Analog Mode Loop Simulator Circuit: A circuit simulating the network
side of the two-wire telephone connection that is used for testing terminal equipment to
be connected to the PSDS Type II loops.
PSTN: Public Switched Telephone Network.
Public Switched Digital Service Type I (PSDS Type I): This service functions only in
a digital mode. It employs a transmission rate of 56 Kbps on both the transmit and
receive pairs to provide a four-wire full duplex digital channel.
Public Switched Digital Service Type II (PSDS Type II): This service functions in
two modes, analog and digital. Analog signaling procedures are used to perform
supervisory and address signaling over the network.
Note: After an end-to-end connection is established, the Switched Circuit Data Service Unit (SCDSU)
is switched to the digital mode.
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Public Switched Digital Service Type III (PSDS Type III): This service functions only
in a digital mode. It uses a time compression multiplexing (TCM) rate of 160 Kbps, over
one pair to provide a full duplex 64 Kbps user channel.
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REN [Ringer Equivalence Number]: A normalized measure of the on-hook electrical
impedance load presented to the PSTN by the CPE.
Note: REN is used to determine the quantity of devices that may be connected to a single telephone
line and still have all those devices ring when that telephone number is called. In most areas,
the sum of the RENs of all devices connected to one line should not exceed five (5.0).
Reverse Battery Interface: An interface, used with DID, where the battery feed is
provided by the CPE instead of the CO and where the CPE uses a signaling method of
polarity reversal to indicate call status towards the CO.
SF [Single Frequency]: SF is a method of network signaling that uses in-band signals.
Note: The SF signaling band is from 2450 Hz to 2750 Hz. The SF guard band is from 800 Hz to 2450
Hz.
Subrate Digital Service: A digital service providing full-time, simultaneous, two-way
transmission of digital signals at speeds as specified in ANSI/TIA-968-A, subclause
4.5.8.
Switched Circuit Data Service Unit (SCDSU): A CPE device, with PSDS
functionality, located between the network Interface and the data terminal equipment.
Note: SCDSU is also sometimes referred to as Network Channel Terminating Equipment).
Switchhook: A term that refers to that component of the telephone terminal equipment
controlling its operating states (See also On-Hook and Off-Hook).
TE: Terminal Equipment.
Test Equipment: Equipment connected at the customer’s premises that is used on the
customer’s side of the network interfaces to measure characteristics of the telephone
network; or
to detect and isolate a communications fault between a terminal equipment entity and
the telephone network.
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Tie Trunk: A private line between two customer premises switching systems.
WAN: Wide Area Network
White Noise: Noise, either random or impulsive type, that has a flat frequency
spectrum over the frequency range of interest.
Zero Level Decoder: A decoder that yields an analog level of 0 dBm at its output when
the input is the digital mW signal (digital equivalent of a 0 dBm, 1000 Hz sine wave).
Zero Level Encoder: An encoder that yields the digital mW signal (digital equivalent of
a 0 dBm, 1000 Hz sine wave) at its output when the input is an analog level of 0 dBm.
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5.1
GENERAL INFORMATION
Safety Warning About The Procedures In This Document
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Some of the tests or procedures specified in this Document may involve the presence of
hazardous voltages and currents or other potential dangers. Some of these hazards
have been identified, and appropriate warnings have been included in the text
specifying such tests or procedures. Appropriate safety precautions are always
recommended when performing any laboratory test or procedure.
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Each test procedure is cross-referenced to the appropriate subclause of the applicable
requirements document. subclause 5.6 provides a test requirement matrix that indicates
the applicable requirement(s) and test guideline(s) for each specific type of network
interface.
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Operation and performance of CPE are affected by the characteristics of the PSTN.
Ideally, the CPE should be evaluated over the expected range of facilities and their
operating characteristics. However, this is impractical and produces results that may
not be repeatable. Thus, circuits were devised that would reasonably simulate those
characteristics of the network that affect the CPE operation from a network harm
viewpoint.
5.2
General Document Structure
Simulator Circuit Theory
The simulators are illustrated in clause 1 of ANSI/TIA-968-A. They simulate the DC
voltage and resistance ranges that the CPE normally encounters when connected to the
network. They also include the AC termination to be used for each application.
Different simulators are used for different CPE applications. The rules permit the use of
an alternative AC termination during signal power compliance tests (see Figure 1.8 in
ANSI/TIA-968-A). This alternative termination may provide a better AC impedance
match for signal power tests.
Certain tests require the use of these simulators over specified operating ranges. Other
implementations may be used provided they present DC and AC voltage and current
characteristics that are equivalent to the characteristics that the applicable loop
simulators in ANSI/TIA-968-A present to the CPE. If alternative loop simulators are
used they should be described in the test report.
The simulators specified in ANSI/TIA-968-A are for compliance testing only. They are
not intended to ensure proper operation of the equipment when connected to the PSTN.
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5.4
Test Conditions
Performance of the tests described in this Document may require artificial conditions of
the EUT not normally achievable. For example, a battery may be used to close a switch
hook relay for application of the surge stresses in the off-hook mode when it is not
practical for the equipment to be normally powered. This philosophy can be extended
to the use of special EUT software.
When artificial means, or companion equipment, or both, are used to condition the EUT
for testing the effect on the test should be evaluated and care should be taken to ensure
accurate test results. Document this in the test report.
5.5
Suggested Equipment List (SEL)
The equipment itemized here will be identified in the Equipment section of each test
procedure in the following format:
e.g. (1) DC voltmeter SEL#22.
where SEL#22 means see Suggested Equipment List, Item (22).
This list itemizes the suggested requirements for test equipment needed to perform the
tests in this bulletin.
(1)
AC current meter: range > 200 mA, minimum frequency range 15 Hz to 68 Hz,
accuracy +3% Full Scale (fsc).
(2)
AC voltage source: output 0 Vrms to 1500 Vrms at 60 Hz, isolated with 10 mA
minimum current sourcing capability.
(3)
AC volt meter: input impedance > 1 megohm, range 0 V to 150 Vrms, minimum
frequency range 15.3 Hz to 68 Hz, accuracy +3%.
(4)
Applicable loop simulator circuit(s) from clause 1 of ANSI/TIA-968-A.
(5)
Bandpass filter: input impedance >100 kilohms, bandpass 200 Hz to 4000 Hz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(6)
Bandpass filter: input impedance >100 kilohms, bandpass 800 Hz to 2450 Hz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(7)
Bandpass filter: input impedance >100 kilohms, bandpass 2450 Hz to 2750 Hz,
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cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(8)
Bandpass filter: input impedance >100 kilohms, bandpass 3995 Hz to 4005 Hz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(9)
Bandpass filter: input impedance >100 kilohms, bandpass 270 kHz to 6 MHz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(10)
Bandpass filter: input impedance >100 kilohms, bandpass 4000 Hz to 6 MHz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(11)
Bandpass filter: input impedance >100 kilohms, bandpass 10 Hz to 4000 Hz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(12)
Bandpass filter: input impedance >100 kilohms, bandpass 100 Hz to 4000 Hz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(13)
Bandpass filter: input impedance >100 kilohms, bandpass 200 Hz to 3200 Hz,
cutoff frequencies at the 3 dB attenuation points, out-of-band roll-off >24 dB per
octave.
(14)
Bandpass filter: input impedance >100 kilohms, bandpass continuously variable
within the cutoff frequency limits of 20 Hz to 10 MHz, cutoff frequencies at the 3 dB
attenuation points, out-of-band roll-off >24 dB per octave.
(15)
Companion terminal equipment.
(16)
Concrete surface covered with 3 mm of asphalt tile.
(17)
Current Source: Maximum Output: 1 A.
(18)
Data generator: output sequence random, maximum data rate >72 kilobits per
second (kbps), output to match data interface.
(19)
DC current meter: range 0 mA to 200 mA, accuracy +3% fsc.
(20)
DC current meter: range 20 microamp (uA), accuracy +3% fsc.
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(21)
DC power supply: output level 0 V to 200 V, maximum output current >1A.
(22)
DC Voltmeter: input impedance >1 megohm, range 0 V to 200 V, accuracy +3%
fsc.
(23)
Digital sampling storage oscilloscope: input impedance >1 megohm, frequency
range >6 MHz, input sensitivity of 3 mV or better, trigger sensitivity of at least 10
mV or better, accuracy +3%.
(24)
Digital sampling storage oscilloscope: input impedance >1 megohm, frequency
range >100 MHz, input sensitivity of 3 mV or better, trigger sensitivity of at least 10
mV or better, sampling rate >500 kHz, single and accumulative trace capability,
channel A minus channel B, accuracy +3%.
(25)
DS1 transmission test set capable of sending a programmed bit stream.
(26)
Frequency counter: input impedance >1 megohm, frequency range from 100 Hz
to at least 10 MHz, input sensitivity of 10 mV or better, resolution <1 Hz, accuracy
+3 Hz.
(27)
Frequency generator: output impedance 600 ohms, frequency range up to at least
4 kHz, maximum output level >40 dBm, sinusoidal output.
(28)
Frequency selective voltmeter: frequency range from 200 Hz to at least 4 kHz,
input impedance >10 kilohms, balanced input, range 1 microvolt to 1 V, accuracy
+3%, bandwidth 10 Hz and 30 Hz.
(29)
(30)
(31)
Hearing aid probe coil assembly: see 47 CFR, 68.316.
Transverse balance bridge: See figure 4.7 of ANSI/TIA-968-A and Note (3) of this
subclause.
Means to record oscilloscope and spectrum analyzer traces.
(32)
Zero level encoder/decoder, may consist of one or more discrete units which
perform this function.
(33)
Ringing Amplifier: Output level to at least 150 Vrms superimposed on 56.5 Vdc,
frequency range 15.3 Hz to 68 Hz.
(34)
Spectrum analyzer: input impedance >1 megohm, frequency range from 10 Hz to
at least 30 MHz, sensitivity of 0.1 mV or better, resolution <1 Hz, accuracy +2 dB.
(35)
Summing Network: input and
output impedances 600 ohms.
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(36)
Type A Surge generator: output 800 V peak, having 10 s maximum front time to
crest and a 560 microsecond (μs) minimum decay time to half crest; with a peak
current capability of 100 A minimum, and the ability to generate these pulses in
both positive and negative polarity.
(37)
Type A Surge generator: output 1500 V peak, having 10 d (s) maximum front
time to crest and a 160 microsecond (s) minimum decay time to half crest; with a
peak current capability of 200 A minimum; and the ability to generate these pulses
in both positive and negative polarity.
(38)
Surge generator: output 2500 V peak, having 2 microsecond (s) maximum front
time to crest and a 10 microsecond (s) minimum decay time to half crest; a peak
current capability of 1000 A minimum; and the ability to generate these pulses in
both positive and negative polarity; means for preventing the surge voltage from
entering the feeding AC power network.
(39)
Tracking generator: output impedance <600 ohms, frequency range from 10 Hz to
at least 6 MHz, maximum output level 0 dBm.
(40)
True rms AC voltmeter: input impedance >100 kilohms, frequency range from 10
Hz to at least 4 kHz, averaging times of 0.1 s and 3.0 s, input sensitivity of 0.7 mV
or better, peak indicating optional, accuracy +3%.
(41)
True rms AC voltmeter: input impedance >100 kilohms, frequency range from 1
kHz to at least 1 MHz, input sensitivity of 35 mV or better (referenced to 135 ohms),
peak voltage and rms voltage indicating, accuracy +3%.
(42)
True rms current meter: range 0 mA to 500 mA, accuracy +3% fsc, measures DC
and rms current simultaneously (e.g., a thermocouple type meter without DC
blocking condenser at the input).
(43)
Voltage source: output 120 Vrms at 60 Hz, output current 10 mA.
(44)
Voltage source: output 300 Vrms at 60 Hz, output current 10 mA.
(45)
White noise generator: output impedance 600 ohms, frequency range from 200
Hz to at least 4 kHz, maximum output level of at least 10 dBm.
(46)
Zero level encoder/decoder: Equipment or companion terminal equipment capable
of encoding and decoding analog signals with zero loss in the bit format appropriate
for the digital interface under test.
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(47)
Type B Metallic Surge Generator: 1000 V minimum peak open circuit voltage at
the output port, with a 9 microsecond (s) front time, ±30%, and a 720 microsecond
(s) decay time, ±20%; 25A minimum peak short circuit current at the output port,
with a 5 s front time, ±30%, and a 320 microsecond (s) decay time, ±20%. The
generator should be able to generate these pulses in either polarity.
(48)
Type B Longitudinal Surge Generator: 1500 V minimum peak open circuit voltage
at each output port simultaneously, with a 9 microsecond (s) front time, ±30%, and
a 720 microsecond (s) decay time, ±20%; 37.5A minimum peak short circuit
current at each output port simultaneously, with a 5s front time, ±30%, and a 320
s decay time, ±20%. The generator should be able to generate these pulses in
either polarity.
(49)
Feeding Bridge with 2 microfarad (F) blocking capacitors and inductors of 1.8
Henries minimum at 200 Hz for analog telephone.
(50)
Test loops: Any real loop or commercially available artificial loop equivalent to 2.7
km and 4.6 km #26 AWG non-loaded cable.
(51)
Artificial ear: The IEC coupler for supra-aural earphones as described in ANSI
S3.7, Method for Coupler Calibration of Earphones, is used for measuring the
acoustic output of receivers that are designed to seal on its circular rim without the
use of sealing putty or similar materials. The pressure response of the microphone
is to be used in determining the sound pressure generated in the coupler by the
receiver.
(52)
Standard microphone: A type (0.5 in) laboratory standard pressure microphone
according to ANSI S1.15 for measuring the sound pressure generated in the
artificial ear. The sensitivity of the microphone should be constant over the
frequency range of 100 Hz to 5000 Hz.
(53)
Microphone amplifier: The frequency response characteristics of this amplifier
should be constant over the frequency range from 100 Hz to 5000 Hz. The inputoutput characteristics of this amplifier should be linear for the range of sound
pressure levels to be measured.
(54)
100 Hz to 5000 Hz sinewave frequency generator, with a sweep speed slow
enough not to reduce the accuracy of the measurement. The generator level
should be constant over a frequency range of 100 Hz to 5000 Hz.
(55)
AC Voltmeter having ranges from 0.01V to 10V (full-scale reading), with an input
impedance greater than 100 kilohms for bridging measurements or equal to 900
ohm for terminated measurements.
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(56)
Signal Analyzer (FFT) having an input impedance >100 kilohms, a frequency
range from 10 Hz to at least 4 kHz, and averaging times of 0.1 s and 3.0 s.
(57)
Spectrum analyzer: input impedance 50 ohms, frequency range from 20 Hz to at
least 30 MHz, sensitivity of –130 dBm/Hz or better, resolution < 1 Hz, absolute
amplitude accuracy +1.5 dB or better.
(58)
Differential amplifier with 10X passive probe set: amplifier gain 1,10, gain accuracy
+1%, bandwidth DC to 10 MHz, output impedance 50 ohms, input impedance >1
megohm, input capacitance 20 pF, bandwidth limit filter upper cutoff frequency 10
kHz, filter response 6 dB/octave, minimum common mode rejection ratio 10000.
(59)
100:50 ohm balun transformer: frequency range 10 kHz to 30 MHz minimum.
(60)
10 dB 50 ohm pad: frequency range DC to 11 MHz minimum.
(61)
High-Pass Filter: fc 3 dB cut off frequency 500 kHz, f/ fc ratio 0.40:1, stop band
attenuation –50 dBc.
(62)
Vector analyzer: input impedance of 50 ohms and 1 megohm, frequency range
from DC to 30 MHz minimum, sensitivity of -130 dBm/Hz or better, resolution < 1
Hz, absolute amplitude accuracy +1.5 dB or better.
(63)
High-Pass Filter: fc 3 dB cut off frequency in the range of 350 kHz to 590 kHz, f/ fc
ratio 0.40:1, stop band attenuation -50 dBc.
(64)
135:50 ohm balun transformer: frequency range 1 kHz to 10 MHz minimum.
(65)
135:50 ohm balun transformer: frequency range 20 Hz to 2 MHz minimum.
(66)
135:50 ohm balun transformer: frequency range 5 MHz to 30 MHz minimum.
(67)
Artificial line: 2743 m (9 kft), 26 AWG.
(68)
Network Tone Generator capable of providing the following dual tone signals:
(a) Dial tone: 350 Hz + 440 Hz, ± 0.7 %, at –10 dBm to –29 dBm per frequency
applied continuously. A level of –13 dBm to –21 dBm per frequency should be
satisfactory for most tests.
(b) Stuttered dial tone: dial tone having a cadence of 0.1 s on, 0.1 s off, ± 10 %, for
10 cycles followed by continuous dial tone.
(c) Busy tone: 480 Hz + 620 Hz, ± 1.5 %, at –21 dBm to –52 dBm per frequency
with a cadence of 0.5 s on, 0.5 s off, ± 10 %. A level of –24 dBm to –32 dBm
per frequency should be
satisfactory for most tests.
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(d)
(e)
(69)
Reorder tone: 480 Hz + 620 Hz, ± 1.5 %, at –21 dBm to –52 dBm per
frequency with a cadence of 0.25 s on, 0.25 s off, ± 10 %. A level of –24 dBm
to –32 dBm per frequency should be satisfactory for most tests.
Audible ringing: 440 Hz + 480 Hz, ± 1.6 %, at –16 dBm to –47 dBm per
frequency with a cadence of 2 s on, 4 s off, ± 10 %. A level of –19 dBm to –27
dBm per frequency should be satisfactory for most tests.
Artificial ear: The Type 3.3 or Type 3.4 artificial ear described in ITUT
Recommendation P.57 is used for measuring the acoustic output of receivers that
are not designed to seal on the SEL#51 artificial ear. The pressure response of
the microphone used with these artificial ears is to be corrected to provide the
sound pressure at the entrance of the ear canal that is used to calculate loudness
ratings. See IEEE 269-2002 for further information
Notes to the Suggested Equipment List:
Note 1.
Any single-ended test equipment used may require a matching/isolation device (e.g.,
transformer) to provide a balanced device. Similarly, an amplifier or similar device may be
required to attain the required output voltage or impedance.
21
Note 2.
Unless otherwise stated, values in dBm are referenced to 600 ohms.
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Note 3.
The transverse balance test circuit for digital circuits is given in Figure 10.2-1.
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Note 4.
The specialized test equipment used in clause 15 is not itemized here. Refer to clause 15
for any equipment details.
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Note 5.
The test equipment used only for the tests described in the Appendices is not itemized
here.
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Note 6.
To comply with 47 CFR Part 68 requirements, regular calibration of all test instruments is
necessary.
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Note 7.
The equipment itemized here will be identified in the Equipment Section of each test
procedure in the following format:
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e.g. (1) DC voltmeter SEL#22, where SEL#22 means see Suggested Equipment List,
Item (22).
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5.6
Test Requirements Matrix
To determine which criteria may be applicable to a specific product, refer to the test
matrix document (in MS Excel format) that forms part of this document.
Some of the tests shown may not be applicable upon examination of the product's
interface or functionality, or after a reading and interpretation of the criteria.
For example, for a loop start interface, the matrix shows a signal power test for network
control signals. However if the product does not generate network control signals, then
this test does not apply.
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6
6.1
ENVIRONMENTAL SIMULATION ANSI/TIA-968-A, 4.2
Sequencing of Environmental Simulations
ANSI/TIA-968-A subclause 4.2 requires that "Unpackaged Certified Terminal Equipment
and Certified Protective Circuitry shall comply with all the criteria specified in this
standard, both prior to and after the application of each of the mechanical and electrical
stresses specified in this section...." For practical reasons, the accepted method for
equipment which has not been affected by environmental simulations is to perform
complete electrical testing, not after each stress but once after all stresses.
Generally, testing should be performed serially; that is, the unit should be tested for
compliance to the electrical requirements, then subjected to the stresses of subclause
6, and finally the unit should be reexamined for compliance to the technical
requirements. This procedure provides an opportunity to evaluate the effects of the
environmental stresses on the unit without uncertainties resulting from the testing of
several different units non-serially.
Circumstances may occasionally require parallel testing of the equipment. In this case,
one unit is subjected to the environmental stresses of subclause 6 while a second unit is
maintained in a non-stressed condition. The two units are then examined for
compliance to the requirements of ANSI/TIA-968-A clause 4. This type of test plan has
several limitations, particularly when the units used for testing are engineering samples
or prototypes. Since one of the objects of the environmental stress testing is to note the
effect of the stresses on the equipment under test, parallel testing of two units may not
always provide enough information. The testing should be performed on a single unit
with tests performed serially as discussed above.
Shown in Figure 6.1-1 is a recommended serial test sequence, with notes and
allowances for failures experienced during test, component replacements and last
minute design changes. Any sequence of environmental simulations may be followed
but should be from least to most destructive. The sequence shown in Figure 6.1-1 is
typical of 'real-world' environmental stresses that are experienced by certified
equipment. Operational tests may be performed once or several times, e.g. after any of
the simulations if failure appears probable or after all simulations have been performed.
The EUT may be considered compliant when all applicable pre- and postenvironmentally obtained data meets 47 CFR Part 68 and ANSI/TIA-968Arequirements. If environmental stresses impair the function of the EUT, good
engineering judgment should be exercised in determining whether the EUT is compliant.
An abbreviated array of post-environmental data may be sufficient to verify compliance.
Alternatively, it may be determined that some repair or special techniques are in order
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to adequately profile the EUT’s post-environmental condition.
Example: Following the sequence suggested, the application of the Type A metallic
surge voltages to the EUT may permanently open the switchhook, which by itself, is not
a compliance failure. However, with the switchhook permanently open, it is thereafter
impossible to evaluate the signal level limitation circuitry, which may also be
malfunctioning, perhaps as a result of thermal conditioning. In an actual installation,
depending on locale and other elements, environmental conditions may thermally stress
the equipment but subject it to infrequent lightning discharge. Such equipment may, via
thermal susceptibility of signal power limitation circuitry, cause harm to the network.
Engineering judgment will determine appropriate procedures in such circumstances.
Operational or electrical testing is not required during environmental simulations. The
EUT should be allowed to stabilize to ambient conditions before evaluation testing
resumes.
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Figure 6.1-1 Environmental Flowchart
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Notes for Figure 6.1-1:
Note 1.
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INITIAL
Initial electrical tests are performed on a fully functional EUT. If the EUT has functions
which are not operational but which do not affect compliance, this should be noted in the
report.
Note 2.
ENVIRONMENTAL NOTES:
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Environmental simulation may take place in ANY sequence; however, based on
engineering analysis of the particular unit under test, simulations should be done in the
order of potentially least destructive to most destructive. Experience has shown the
sequence diagrammed to be the least to most destructive for most equipment.
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Engineering judgment may suggest an operational test or a complete test to 47 CFR Part
68 / ANSI/TIA-968-A requirements if it appears the next simulation may be destructive, or
the previous one may have damaged the EUT.
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Note 3.
OPERATIONAL FAILURE:
16
(Example: Data modem will not transmit data.)
17
18
“Operational failure” means the device will not function normally or as intended.
Measurement may or may not be necessary.
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21
Such a condition does not mean failure of 47 CFR Part 68 / ANSI/TIA-968-A. This can
only be determined by completing all applicable tests on the equipment and verifying
compliance with 47 CFR Part 68 / ANSI/TIA-968-A.
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Note 4.
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COMPONENT REPLACEMENT
Replacement of failing components and continuation of the post-simulation testing should
only occur after good engineering analysis indicates that this is an acceptable procedure.
The replacement components should be subjected to the same conditioning as the EUT
has encountered to that point.
Note 5.
POST - ENVIRONMENTAL TESTS
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For a unit, which has not experienced failures due to environmental conditioning, to be
considered compliant, it should have pre- and post -environmental simulation test data,
thus verifying compliance with all applicable 47 CFR Part 68 and ANSI/TIA-968-A
requirements.
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For a unit which has experienced failures due to environmental conditioning to be
considered compliant, good engineering judgment should be exercised in determining
which 47 CFR Part 68 / ANSI/TIA-968-A requirements remain applicable, and what
comparison post-environmental data is required (and what techniques are employed in
acquiring such data).
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Note 6.
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6
REPAIR, REDESIGN OR RE-SPECIFICATION OF COMPONENTS:
Since changes may invalidate entire blocks of pre-environmental data, usually a return to
the beginning of the test cycle is in order. If re-entry at a later point in the flow chart
appears permissible, it should be noted in the approval report with justification.
Note 7.
APPROVAL DOCUMENTATION or APPLICATION SUBMISSION
Refer to current issue of TIA/TSB-129-A.
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Mechanical Shock ANSI/TIA-968-A, 4.2.1
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3
4
5
6
7
6.2.1 Background
Terminal equipment may be subjected to mechanical shock during shipping, installation,
and use. This shock may damage or reposition components in circuitry affecting
compliance. Mechanical shocks condition the EUT to reveal component or position
weaknesses.
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6.2.2 Purpose
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6.2.3 Equipment
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To simulate handling of terminal equipment during installation and use.
(1)
Concrete surface SEL#16.
Note: Refer to subclause 5.5 for equipment details.
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6.2.4 Equipment States Subject To Test
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6.2.5 Procedure
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6.2.6 Alternative Methods
None.
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6.2.7 Suggested Test Data
Unpackaged and unpowered.
Refer to ANSI/TIA-968-A subclause 4.2.1 for procedure and equipment weight
classification.
(a)
Weight and use classification of EUT.
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(b)
Number of drops.
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(c)
Height and orientation of drop.
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(d)
Observed results.
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6.2.8 Comments
None.
6.3
Telephone Line Surge - Type A, Metallic. ANSI/TIA-968-A, 4.2.2.1
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6.3.1 Background
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6.3.2 Purpose
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6.3.3 Equipment
The metallic surge is the voltage resulting from the longitudinal-to-metallic conversion
when one of the two primary protectors operates. Surge tests simulate longitudinal
voltage transients in the telephone company lines due to lightning. The front and decay
times and crest values are derived from actual measurements with primary protectors in
typical installations. These surges, particularly in equipment off-hook conditions, can
easily cause compliance-related equipment failure via destruction of sensitive electronic
circuitry as the surges appear in the same mode as network voice and data signals and
signaling information.
To simulate induced metallic surge voltages on a telephone line which could result from
lightning.
(1)
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Surge Generator SEL#36.
Note: Refer to subclause 5.5 for equipment details.
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6.3.4 Equipment States Subject To Test
(1)
On-hook.
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(2)
Off-hook.
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(3)
Any other state in which the EUT is normally connected to the network.
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6.3.5 Procedures
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
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(1)
Refer to ANSI/TIA-968-A subclause 4.2.1.1.1 for the connections to be surged.
2
(2)
Place the equipment in the state to be tested.
3
(3)
Apply a surge of each polarity.
4
(4)
Check EUT operation and record the results.
5
(5)
Change states as necessary and repeat Step (2) through Step (4).
6
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6.3.6 Alternative Methods
9
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6.3.7 Suggested Test Data
(1)
Equipment state(s).
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(2)
Leads tested.
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(3)
Observed Results.
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6.3.8 Comments
(1)
All EUT leads not being surged should be terminated in a manner no less severe
than that which occurs in normal use.
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(2)
A loop simulator may be used as long as it does not interfere with application of
stress to the EUT.
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(3)
The EUT is permitted to reach certain failure modes after application of these surges.
See ANSI/TIA-968-A subclause 4.2.2.3 for discussion.
None.
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6.4
Telephone Line Surge - Type A, Longitudinal. ANSI/TIA-968-A, 4.2.2.2
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6.4.1 Background
The longitudinal surge is the ground potential rise resulting from current in the primary
protector grounding conductor as a result of both primary protectors operating.
Equipment with a good dielectric/low capacitance barrier does not usually sustain
damage as a result of this surge.
8
9
10
11
6.4.2 Purpose
12
13
14
6.4.3 Equipment
To simulate longitudinal surge voltages which could result due to lightning strikes on the
telephone line.
(1)
15
16
Surge generator SEL#37.
Note: Refer to subclause 5.5 for equipment details.
17
18
19
20
6.4.4 Equipment States Subject To Test
(1)
On-hook.
21
(2)
Off-hook.
22
(3)
Any other state in which the EUT is normally connected to the network.
23
24
25
26
27
28
29
30
6.4.5 Procedure
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
Refer to ANSI/TIA-968-A subclause 4.2.2.2.1 for the connections to be surged.
(1)
Place the EUT in the state to be tested.
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(2)
Apply a surge of each polarity.
2
(3)
Check EUT operation and record the results.
3
(4)
Change states as necessary and repeat Step (3) and Step (4).
4
5
6
6.4.6 Alternative Methods
7
8
9
6.4.7 Suggested Test Data
None.
(1)
Equipment state(s).
10
(2)
Leads tested.
11
(3)
Observed Results.
12
13
14
15
6.4.8 Comments
(1)
Terminate EUT leads not being surged in a manner which is no less severe than
occurs in normal use.
16
17
(2)
A loop simulator may be used as long as it does not interfere with application of
stress to the EUT.
18
19
(3)
The EUT is permitted to reach certain failure modes after application of these surges.
See ANSI/TIA-968-A subclause 4.2.2.3 for discussion.
20
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6.5
Telephone Line Surge - Type B, Metallic. ANSI/TIA-968-A, 4.2.3.1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
6.5.1 Background
20
21
22
23
6.5.2 Purpose
24
25
26
6.5.3 Equipment
It is possible for low energy transients to couple to the telephone lines and enter an
interface without tripping the secondary protectors. The transients in ANSI/TIA-968-A
subclause 4.2.3 simulate these low energy disturbances and address potential harms to
the network after their incidence upon an interface. There is a significant body of data
which indicates that the energy of the FCC Type A surge is very severe relative to
actual surges that occur. The concern with the FCC Type A surge is that the response
of equipment to lower energy surges, which are more common, is unknown.
The metallic surge is the voltage resulting from the longitudinal-to-metallic conversion
when one of the two primary protectors operates. Surge tests simulate longitudinal
voltage transients in the telephone company lines due to lightning. The front and decay
times and crest values are derived from actual measurements with primary protectors in
typical installations. These surges, particularly in equipment off-hook conditions, can
easily cause compliance-related equipment failure via destruction of sensitive electronic
circuitry as the surges appear in the same mode as network voice and data signals and
signaling information.
To simulate low energy induced metallic surge voltages on a telephone line which could
result from lightning.
(1)
27
28
Surge Generator SEL#47.
Note: Refer to subclause 5.5 for equipment details.
29
30
31
6.5.4 Equipment States Subject To Test
(1)
On-hook.
32
(2)
Off-hook.
33
(3)
Any other state in which the EUT is normally connected to the network.
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2
3
4
5
6.5.5 Procedures
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
Refer to ANSI/TIA-968-A subclause 4.2.3.1 for the connections to be surged.
6
7
(1)
Place the equipment in the state to be tested.
8
(2)
Apply a surge of each polarity.
9
(3)
Check EUT operation and record the results.
10
(4)
Change states as necessary and repeat Step (2) through Step (4).
11
12
13
6.5.6 Alternative Methods
14
15
16
6.5.7 Suggested Test Data
(1)
Equipment state(s).
17
(2)
Leads tested.
18
(3)
Observed Results.
19
20
21
22
6.5.8 Comments
(1)
All EUT leads not being surged should be terminated in a manner no less severe
than that which occurs in normal use.
23
24
(2)
A loop simulator may be used as long as it does not interfere with application of
stress to the EUT.
25
26
(3)
Verify that the EUT complies with the failure criteria outlined in ANSI/TIA-968-A
subclause 4.2.3.3 after surge.
27
28
29
30
31
(4)
The surge generator waveform parameters specified are based on an analysis of the
surge generator circuit of ITU Recommendation K.21. This recommendation
specifies a nominal open circuit voltage waveform of 10 microseconds (s) x
700 microseconds (s). Commercial surge generators are generally built to the ITU
Recommendation and the 10 microseconds (s) x 700 microseconds (s) waveform
None.
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2
3
4
provided is within the tolerances of the 9 microseconds (s) x 720 microseconds (s)
open circuit waveform specified in ANSI/TIA-968-A subclauses 4.2.2.1.2 – 4.2.2.2.2.
Surge generators conforming to the ITU Recommendation also meet ANSI/TIA-968A subclauses 4.2.2.1.2 – 4.2.2.2.2.
5
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2
3
4
5
6
(5)
Verify that the equipment is capable of withstanding the energy of the Type B surges
without causing permanent opening or shorting of the interface circuit and without
sustaining other damages that will affect compliance. The EUT is not required to be
fully operational. These criteria for allowable failure modes help ensure that a
protection strategy for meeting the acceptable failure mode criteria of the Type A
surge does not mask other potentially harmful failure modes at lower energies.
7
8
9
10
(6)
Where the EUT will not switch from an on-hook to an off-hook state after stress, due
to a failure of some circuitry that controls or powers a hookswitch relay or other
similar device, an artificial means should be used to place the EUT in the off-hook
state. All applicable off-hook tests and all on-hook tests should be performed.
11
12
(7)
The EUT is not to open the interface circuit by opening a trace, fuse, or component in
the interface circuit.
13
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6.6
Telephone Line Surge - Type B, Longitudinal. ANSI/TIA-968-A, 4.2.3.2
2
3
4
5
6
7
6.6.1 Background
The longitudinal surge is the ground potential rise resulting from current in the primary
protector grounding conductor as a result of both primary protectors operating.
Equipment with a good dielectric/low capacitance barrier usually does not sustain
damage as a result of this surge.
8
9
10
6.6.2 Purpose
11
12
13
6.6.3 Equipment
To simulate low energy longitudinal surge voltages induced by lightning.
(1)
14
15
Surge generator SEL#48
Note: Refer to subclause 5.5 for equipment details.
16
17
18
6.6.4 Equipment States Subject To Test
(1)
On-hook.
19
(2)
Off-hook.
20
(3)
Any other state in which the EUT is normally connected to the network.
21
22
23
24
25
6.6.5 Procedure
26
(1)
Place the EUT in the state to be tested.
27
(2)
Apply a surge of each polarity.
28
(3)
Check EUT operation and record the results.
29
(4)
Change states as necessary and repeat step (3) and step (4).
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
Refer to ANSI/TIA-968-A subclause 4.2.2.2.1 for the connections to be surged.
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2
3
6.6.6 Alternative Methods
4
5
6
6.6.7 Suggested Test Data
(1)
Equipment state(s).
7
(2)
Leads tested.
8
(3)
Observed Results.
None.
9
10
11
12
6.6.8 Comments
(1)
Terminate EUT leads not being surged in a manner which is no less severe than
occurs in normal use.
13
14
(2)
A loop simulator may be used as long as it does not interfere with application of
stress to the EUT.
15
16
(3)
Verify that the EUT complies with the failure criteria outlined in ANSI/TIA-968-A
subclause 4.2.2.3 after surge.
17
18
19
20
21
22
23
24
25
(4)
The surge generator waveform parameters specified are based on an analysis of the
surge generator circuit of ITU Recommendation K.21. This recommendation
specifies a nominal open circuit voltage waveform of 10 microseconds (s) x
700 microseconds (s). Commercial surge generators are generally built to the ITU
Recommendation and the 10 microseconds (s) x 700 microseconds (s) waveform
provided is within the tolerances of the 9 microseconds (s) x 720 microseconds ()
open circuit waveform specified in ANSI/TIA-968-A subclauses 4.2.2.1.2 – 4.2.2.2.2.
Surge generators conforming to the ITU Recommendation also meet ANSI/TIA-968A subclauses 4.2.2.1.2 – 4.2.2.2.2.
26
27
28
29
30
31
(5)
Verify that the equipment is capable of withstanding the energy of the Type B surges
without causing permanent opening or shorting of the interface circuit and without
sustaining other damages that will affect compliance. The EUT is not required to be
fully operational. These criteria for allowable failure modes help ensure that a
protection strategy for meeting the acceptable failure mode criteria of the Type A
surge does not mask other potentially harmful failure modes at lower energies.
32
33
34
(6)
Where the EUT will not switch from an on-hook to an off-hook state after stress, due
to a failure of some circuitry that controls or powers a hookswitch relay or other
similar device, an artificial means should be used to place the EUT in the off-hook
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2
3
state. All applicable off-hook tests, and all on-hook tests should be performed.
(7)
The EUT is not to open the interface circuit by opening a trace, fuse, or component in
the interface circuit.
4
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6.7
2
3
4
5
6
6.7.1 Background
7
8
9
6.7.2 Purpose
10
11
12
Power Line Surge ANSI/TIA-968-A, 4.2.4
Lightning induced transients may enter the equipment via the AC power lines. As such,
they will typically be superimposed on the normal line voltage and may cause damage
or destruction to the ac-line-input dielectric barrier.
To simulate lightning induced surges on the AC power lines.
6.7.3 Equipment
(1)
13
14
Surge generator SEL#38.
Note: Refer to subclause 5.5 for equipment details.
15
16
17
6.7.4 Equipment States Subject To Test
(1)
Powered with EUT power switch ON.
18
(2)
Powered with EUT power switch OFF.
19
20
21
22
23
6.7.5 Procedure
24
(1)
Apply three surges of each polarity to the power connection of the EUT.
25
(2)
Change EUT states and repeat Step (1).
26
(3)
Perform an operational check of the EUT and record the results.
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
Refer to ANSI/TIA-968-A subclause 4.2.4.1 for the connections to be surged.
27
28
29
6.7.6 Alternative Methods
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None.
2
3
4
6.7.7 Suggested Test Data
(1)
Voltage.
5
(2)
Equipment state(s).
6
(3)
Number of surges and polarity.
7
(4)
Observed results.
8
9
10
6.7.8 Comments
11
12
(1)
All equipment leads not being surged should be terminated in a manner which is no
less severe than that which occurs in normal use.
13
14
(2)
The EUT is permitted to reach certain failure modes after application of these surges.
See ANSI/TIA-968-A subclause 4.2.4.2 for discussion.
15
16
(3)
Configure the test arrangement to apply the surge to the EUT without affecting, or
being affected by, the AC power line.
17
18
19
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
7
LEAKAGE CURRENT LIMITATIONS (ANALOG AND DIGITAL) ANSI/TIA-968-A,
4.3
7.1 Background
Leakage current limitations ensure that telephone connections are adequately insulated
against voltages hazardous to telephone company personnel as a result of supply
voltages within the equipment or the result of accidental contact with commercial power
on 1) exposed conductive surfaces, 2) leads to other equipment, e. g. serial, parallel,
LAN, WAN, or 3) other leads to the network interface. In this case, the leakage current
limit is merely a threshold for determining whether dielectric breakdown has occurred. It
should not be confused with leakage current limits that relate to product safety. Such
limits typically specify the maximum current permitted through an impedance simulating
the human body connected between exposed conductive surfaces and ground or
between exposed conductive surfaces.
The 1000-volt requirement is based in part upon the fact that potentials as high as 1000
V peak can reach certified terminal equipment or certified protective circuitry where
carbon block protectors have not fired. The 1500-volt requirement is based upon
commonly used criteria for testing transformer insulation that specifies using 1000 volts
plus twice the rated primary voltage.
The increase in leakage current limit allowed for multi-unit equipment is for those cases
where more than one unit is connected to the same telephone connection leads. It
takes into account the increased leakage current resulting from the capacitance in: 1)
interconnecting cables and 2) the parallel combination of dielectric barriers in each unit.
7.2 Purpose
To verify the integrity of the dielectric barrier between the network and power line and
the equipment connections of the EUT.
7.3 Equipment
(1) AC voltage source SEL#2.
(2) True rms voltmeter SEL#40 (qty 2).
Note: Refer to subclause 5.5 for equipment details.
40
41
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
7.4 Equipment States Subject to Test
The EUT-to-network barrier test (1000 V) should be performed in a sufficient number of
operational states to verify compliance of all dielectric barrier components, e.g., line
transformers, opto-isolators, relays and printed circuit boards. By using the required
isolated source, these tests may be performed with or without power applied to the
EUT. Artificial means to achieve the various test modes may be used when required,
provided the method used does not affect the current path. For example, the network
connections of a switchhook relay is not to be manually shorted. Instead, an external
supply, such as a battery, may be used to activate the relay to achieve the off-hook
mode. For the EUT-to-power-line barrier test (1500 V), the power switch is in the ON
position, but the EUT is not powered so that the power path is completed when the high
voltage is applied.
7.5 Procedure
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
(1)
Connect the EUT to the test circuit of Figure 7-1.
(2)
Select the appropriate EUT test points, and connect to the test setup output.
(3)
Place the EUT in the first test state.
(4)
Gradually increase the test voltage to the level required for the connections under
test, over a 30-second period. Maintain the maximum voltage level for an
additional 60 s.
(5)
Monitor the resulting current and the applied voltage level for the 90-second test
period.
(6)
Record the maximum current measured during this period.
(7)
Adjust the source for zero-volt output.
(8)
Repeat Step (4) through Step (7) for all applicable operational states.
(9)
Repeat Step (2) through Step (8) for all specified combinations of electrical
connections as listed in subclause 4.3 of ANSI/TIA-968-A.
7.6 Alternative Methods
The 1500 VAC test may be conducted using a DC equivalent of 2121 VDC.
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2
3
4
7.7 Suggested Test Data
Identify electrical connections or test points.
5
Voltage applied (V rms).
6
Maximum current (mA peak).
7
8
9
10
7.8 Comments
(1)
Leads may be tested as a group or as indicated in subclause 4.3 of ANSI/TIA-968-A.
11
12
13
14
15
16
(2)
EUTs with a nonmetallic case having some exposed metallic surfaces (e.g., screws,
hinges, ventilation or access opening) may be tested by wrapping the case in a
conductive foil, placing it on a conductive sheet, or immersing it in a container filled
with 0.25-inch-diameter (maximum) conductive particles, as appropriate. The
voltage is applied between the conducting element and the other relevant test
points.
17
18
(3)
As shown in the test setup, the leakage current is equal to the voltage measured
across the 1000-ohm resistor divided by 1000.
19
(4)
There are three intentional paths to ground considered:
20
21
22
23
24
25
26
(a)
Operational paths, such as ground start leads, are excluded from testing. An
operational path is identified as having a DC resistance at operating voltages
(battery or ringing). The current handling capability of the path is evaluated
under subclause 4.4.5.1 of ANSI/TIA-968-A. Another example of an excluded
operational path is the Tip Ground state of a central office implemented
telephone because it provides an intentional operational path, from the tip
conductor through a reset electromagnet in series with a coin relay, to ground.
27
28
29
30
31
32
33
(b)
Protective paths, such as MOVs and surge suppressors, are removed before
testing. A protective path is identified as being conductive at leakage current
test voltages (1000 V -- a surge arrestor fires to protect equipment from such
voltages), but is an insulator at operational voltages. The insulation properties
of the component removed is evaluated at 120 V under subclause 4.4.5.2 of
ANSI/TIA-968-A. Typically, a suppressor is rated at greater than 130 V to be
transparent to ringing voltages.
34
35
36
(c)
Filter paths on the interface circuit are left in place during testing. Filter
components should withstand 1000 V, which provides the capability to
withstand surges. These paths are identified as not conductive for DC. To
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
pass a 1000 V test, a capacitor needs about a 400 WVDC rating. These are
special capacitors, designated “X-capacitors”, or “Y-capacitors”.
(5)
EMI filtering on the AC input to the EUT may be disconnected from ground. An
engineering evaluation is to be made and an attestation provided if the filter cannot
be isolated from ground. Alternatively, power supplies may incorporate integrated
line filter networks, the removal of which would reduce the effect of the applied
voltage in evaluating the characteristics of the EUT. In such cases, it may be
appropriate to perform this test using a DC test voltage. The maximum DC test
voltage would correspond to the peak value of the specified AC test voltage, and the
test should be performed in both polarities.
(6)
If the EUT has a path to ground (or a path close to ground potential) and the high
voltage source is not isolated, measured current inaccuracies may occur due to
ground loops.
(7)
An EUT which has both an intentional operational and an intentional protective path
to ground needs to meet only the requirements of subclause 4.4.5.1 of ANSI/TIA968-A referred to in subclause 7.4 of this Document, provided that it uses varistors,
thyristors, or other protection devices to ground. Examples of these circuits are DID,
OPS, E&M, and Ground Start (which typically utilize ground for operation).
21
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(8)
When conducting the 1500V AC dielectric test between AC power and tip-ring
interface circuit, high leakage current may exist due to loopback current through
common ground and filter paths on AC power side and interface circuit.
4
5
6
7
8
(5)
Note 1.
A 1500 V AC voltmeter or a resistive voltage divider and high impedance voltmeter may be
used.
9
10
Note 2.
The 50-kilohm current-limiting resistor is optional but is recommended to reduce the
possibility of damage in case of insulation breakdown.
11
12
13
Note 3.
A true rms or rms-calibrated voltmeter may be used to measure a converted rms current
limit. Alternatively, an oscilloscope may be used to measure peak current. Precautions
should be taken for isolation of high voltage differential or current probes.
14
15
Figure 7-1. Leakage Current
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2
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8
8.1
HAZARDOUS VOLTAGE LIMITATIONS ANSI/TIA-968-A, 4.4
Hazardous Voltage Limitations, General ANSI/TIA-968-A, 4.4.1
4
5
6
7
8
9
10
11
8.1.1 Background
12
13
14
15
8.1.2 Purpose
16
17
18
8.1.3 Equipment
19
20
21
22
8.1.4 Equipment States Subject to Test
23
24
25
8.1.5 Procedure
When telephone company personnel perform maintenance and repair on the telephone
wiring, they are aware of the various voltages which can be present under normal
operating conditions. If unexpected foreign potentials appear at tip and ring, these
personnel may be injured either by the voltage itself or as a result of physical reaction to
this voltage. Past experience has shown that voltages above 70 volts which are present
for more than one second are hazardous.
This test is to ensure that the EUT does not apply voltages to tip and ring which are not
part of the normal operation of the telephone network.
Digital sampling oscilloscope SEL #23
Any condition which might cause AC voltage to appear on network connections other
than network control signaling, alerting, and supervision.
(1)
Connect the oscilloscope leads to tip and ring leads.
26
(a)
Place the EUT in the state being measured.
27
28
(b)
Observe the AC voltage. If no voltages greater than 70 volts peak are
observed, record the maximum peak voltage.
29
30
(c)
If voltage greater than 70 volts is observed, record the peak voltage and the
time the voltage is present.
31
(2)
Connect the oscilloscope leads from tip to ground.
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(3)
Repeat steps (1)(a) through (d).
2
(4)
Connect the oscilloscope leads from ring to ground.
3
(5)
Repeat steps (1)(a) through (d).
4
5
6
8.1.6 Alternative Method
None suggested.
7
8
9
10
11
8.1.7 Suggested Test Data
(1)
Maximum peak AC voltage measured if less than 70 volts peak.
12
(2)
Maximum and duration if peak AC voltage is greater than 70 volts..
13
14
15
8.1.8 Comments
For Tip - Ring, Tip - Ground, and Ring - Ground:
None.
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2
8.2
Hazardous Voltage Limitations, E&M ANSI/TIA-968-A, 4.4.1.1, 4.4.1.2, 4.4.1.3
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
8.2.1 Background
19
20
21
22
23
8.2.2 Purpose
24
25
26
8.2.3 Equipment
(1)
DC current meter SEL#19.
27
(2)
DC voltmeter SEL#22.
28
(3)
Digital sampling storage oscilloscope SEL#23.
29
(4)
Trace recording device SEL#31.
30
(5)
True rms AC voltmeter SEL#41.
31
32
E&M leads provide DC signaling between equipment units on the same premises. They
have a limited signaling range and are commonly used in the PBX environment
between tie trunk circuits and associated telephone company line signaling circuits,
such as those used for long range DC signaling (DX) or single-frequency signaling (SF).
ANSI/TIA-968-A addresses two types of E&M lead interfaces: one using ground return,
referred to as Type I and the other using metallic return, referred to as Type II. The "A"
and "B" sides each refer to a specific portion of the E&M signaling circuit as shown in
Figure 1.5 and 1.6 of ANSI/TIA-968-A. The "A" side contains the E-lead detector and
the "B" side contains the M-lead detector. Either side may be provided by the approved
terminal equipment, but normally a PBX tie trunk circuit provides the "A" side. There
may also be cases where the approved terminal equipment provides the "B" side. For
example, a line concentrator that could be interposed either between a PBX tie trunk
circuit and a telephone company line signaling circuit, or between two line signaling
circuits at an intermediate location, would require both an "A" side and a "B" side.
To verify that the E&M circuitry provided by approved terminal equipment does not
generate steady-state or transient conditions that can harm telephone company
personnel or equipment.
Note: Refer to subclause 5.5 for equipment details.
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8.2.4 Equipment States Subject to Test
11
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8.2.5 Procedure
(1)
DC current to ground.
19
(2)
Ground the lead through the current meter, and measure the resulting current.
20
(3)
AC voltage to ground.
E&M leads have two active states: idle (on-hook) and operated (off-hook). With either
Type I or Type II, the E lead is open in the idle state and grounded in the operated state
by a contact on the "B" side. Likewise, with Type I, the M lead is grounded in the idle
state and connected to battery through a current limiting device in the operated state by
contacts on the "A" side. With Type II, the M lead is open in the idle state and
connected to battery through a similar current limiting device also by contacts on the "A"
side.
Unless otherwise specified below, all tests should be made in the idle state.
Lead designations are the same as in subclause 4.4.1.1 and subclause 4.4.1.3 of
ANSI/TIA-968-A. Requirements for specific cases should be selected from Table 8.2-1,
as appropriate. The five types of tests listed in this table are referred to as:
21
22
23
Connect AC voltmeter between designated lead and ground, and measure the
voltage.
(4)
24
25
26
27
28
29
DC voltage to ground.
Connect DC voltmeter across a 20 kilohm +/-10% resistor located between
designated lead and ground, and measure the voltage.
(5)
Surge suppression.
Examine a schematic of the E&M circuit, and determine if means are provided to limit
the DC voltage (referenced to ground) to 60 V while providing a power dissipation of
0.5 W.
30
31
32
Note: This is provided by Surge Suppression (SS) in Figure 1.5 of ANSI/TIA-968-A. See Comment
(1).
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(6)
2
3
4
5
6
7
Contact Protection.
Compliance can be verified either by examining a circuit diagram of the E&M circuit
or by measuring voltages across contacts as shown in Figure 8.2-1. Verification is
required only if the E-lead detector on the "A" side is inductive. Verify, by circuit
examination, that contact protection is provided across the winding to limit:
1. the peak voltage to 300 V,
8
2. the rate of change of voltage to 1 volt per microsecond (V/s), and
9
3. the voltage level to 60 V or less after 10 ms (See Comment (2)).
10
11
(6)
Voltage measurements
12
1. Connect the EUT to the test circuit of Figure 8.2-1.
13
2. Open switch S1 and record the oscilloscope trace.
14
15
16
17
8.2.6 Alternative Methods
18
19
20
8.2.7 Suggested Test Data
None suggested.
(1)
The tested lead, and as appropriate:
21
(a)
DC current to ground;
22
(b)
AC voltage to ground;
23
(c)
DC voltage to ground;
24
(d)
Verification of M lead surge suppression;
25
(e)
Verification of contact protection.
26
(f)
27
28
(2)
29
8.2.8 Comments
Where compliance is verified by inspection, include a short discussion describing the
means provided.
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(1)
(2)
Traditionally, M-lead surge suppression is provided on the "A" side of the interface.
In older circuits using mercury-wetted or wire-spring relay contacts it was a 1000ohm resistor between the M lead and ground. A more energy efficient method is
achieved by using a zener diode (typically with a breakdown voltage of 68 V) in
series with the 1000-ohm resistor. If dial pulsing is not required, the 1000-ohm
resistor can be omitted.
The E-lead contact protection circuit is normally connected across the detector. The
limits specified are based on the characteristics of contact protection commonly used
in the industry. Contact protection is typically a series RC circuit. The value of C is
chosen so that the voltage developed across it does not exceed 300 V. This
requirement can be satisfied using the following relationship:
 I 
C
 300 
13
14
15
16
17
18
19
2
L
where:
C is the capacitance in microfarads (F)
I is the current in A, through the inductive load when the contact opens
L is the inductance of the load in H.
The voltage rise limit of 1 volt per microsecond (V/s) is satisfied when:
 F
C F  I A  1

 A
20
21
22
23
Other methods of transient suppression for inductive loads include placing a diode
in series with a zener diode or a varistor across the inductor.
24
(3)
Refer to subclause 4.4.3 for the definition of non-hazardous voltage.
25
26
27
Table 8.2-1
E&M Leads to be Tested
Interface Type
Side of the Interface
Lead to be Tested
1
2
3
4
Type I
A
B
E M E M
DC Current to Gnd X
AC Voltage to Gnd X X X X
DC Voltage to Gnd X X X X
Surge Suppression
X
59
Type II
A
B
E SG M SB E SG M SB
X
X
X X X X X X X X
X X X X X X X X
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Contact Protection
X
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E or M Lead
Storage
Oscilloscope
S1
EUT
See
Note
Note: S1 consists of the contacts of a relay which are designed to be free of contact bounce, such as
those provided in a mercury-wetted relay.
Figure 8.2-1 E or M-Lead Contact Protection
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8.3
Hazardous Voltage Limitations, OPS ANSI/TIA-968-A, 4.4.1.4
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3
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8.3.1 Background
14
15
16
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8.3.2 Purpose
18
19
20
8.3.3 Equipment
(1)
DC voltmeter SEL#22.
21
(2)
True rms AC voltmeter SEL#41.
The Off Premises Station (OPS) function in CPE provides loop start line signaling
similar to that normally provided by a CO line circuit. This means that it provides not
only the battery necessary for talking and DC signaling but also the AC ringing voltage
for signaling from the CPE to the station equipment. A network private line facility
connects the OPS line circuit with the remote station equipment. Thus, there are two
network interfaces, one at each end of the private line facility. Approved station
equipment is used as the off premises station. The hazardous voltage requirements for
OPS ports were written to protect network personnel. The AC voltage limit for ringing
exceeds the combined AC/DC limit for non-hazardous voltages, but is to meet specific
duration requirements to render it non-hazardous.
To verify that the OPS line interface complies with the specified AC and DC voltage
limits.
22
Note: Refer to subclause 5.5 for equipment details.
23
24
25
8.3.4 Equipment States Subject to Test
(1)
Idle open circuit.
26
(2)
Ringing open circuit.
27
28
29
30
8.3.5 Procedure
31
(1)
In the idle open circuit state, measure the DC voltage with the DC voltmeter
connected between:
(a)
T(OPS) and R(OPS);
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(b)
T(OPS) and ground;
2
(c)
R(OPS) and ground.
3
4
(2)
In the idle open circuit state, measure the extraneous AC voltage with the AC
voltmeter connected between:
5
(a)
T(OPS) and R(OPS);
6
(b)
T(OPS) and ground;
7
(c)
R(OPS) and ground.
8
9
(3)
In the ringing open circuit state, confirm that the ringing signal is applied to the proper
lead by measuring the AC voltage with the AC voltmeter connected between:
10
(a)
T(OPS) and ground;
11
(b)
R(OPS) and ground.
12
13
(4)
Perform tests specified in subclause 8.8 to verify compliance with ringing source
requirements.
14
15
16
8.3.6 Alternative Methods
17
18
8.3.7 Suggested Test Data
19
(1)
None suggested.
DC voltages during idle open circuit state:
20
(a)
T(OPS) and R(OPS);
21
(b)
T(OPS) and ground;
22
23
24
(c)
R(OPS) and ground
(2)
Extraneous AC voltages during idle open circuit state:
25
(a)
T(OPS) and R(OPS);
26
(b)
T(OPS) and ground;
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(c)
(3)
R(OPS) and ground.
Ringing AC voltages during ringing open circuit state:
3
(a)
T(OPS) and ground;
4
(b)
R(OPS) and ground.
5
(4)
Verification of proper application of ringing.
6
(5)
Test data as specified in subclause 8.8.7.
7
8
9
10
11
12
13
14
8.3.8 Comments
Test results that comply with the requirements of ANSI/TIA-968-A, 4.4.1.4 as tested
here also satisfy the signal power requirements in ANSI/TIA-968-A, 4.5.2.7.1 and
4.5.2.7.2.
Refer to 4.4.3 for the definition of non-hazardous voltage source.
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8.4
Hazardous Voltage Limitations, DID ANSI/TIA-968-A, 4.4.1.5
8.4.1 Background
The Direct Inward Dialing (DID) function in CPE provides some loop start line signaling
similar to that normally provided to by a CO line circuit. Although it does not provide the
AC ringing voltage like OPS, it does provide battery for DC signaling. The hazardous
voltage requirements were written for DID to protect network personnel.
9
10
11
8.4.2 Purpose
12
13
14
8.4.3 Equipment
(1)
DC voltmeter SEL#22.
15
(2)
True rms AC voltmeter SEL#41.
To verify that the DID interface complies with the specified DC voltage limits.
16
Note: Refer to subclause 5.5 for equipment details.
17
18
19
8.4.4 Equipment States Subject to Test
20
21
22
23
8.4.5 Procedure
Idle open circuit.
(1)
In the idle open circuit state, measure the DC voltage with the DC voltmeter
connected between:
24
(a)
T and R;
25
(b)
T and ground;
26
(c)
R and ground.
27
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30
(2)
In the idle open circuit state, measure the extraneous AC voltage with the AC
voltmeter connected between:
(a)
T and R;
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(b)
T and ground;
2
(c)
R and ground.
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4
5
8.4.6 Alternative Methods
6
7
8
8.4.7 Suggested Test Data
None suggested.
(1)
DC voltages during idle open circuit state:
9
(a)
T and R;
10
(b)
T and ground;
11
(c)
R and ground.
12
13
(2)
Extraneous AC voltages during idle open circuit state:
14
(a)
T and R;
15
(b)
T and ground;
16
(c)
R and ground.
17
18
19
20
8.4.8 Comments
Refer to subclause 4.4 of ANSI/TIA-968-A for the definition of non-hazardous voltage.
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8.5
Hazardous Voltage Limitations, LADC ANSI/TIA-968-A, 4.4.1.6
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3
4
5
6
7
8
9
10
11
12
8.5.1 Background
13
14
15
16
8.5.2 Purpose
17
18
19
8.5.3 Equipment
(1)
DC voltmeter SEL#22.
20
(2)
Digital sampling storage oscilloscope SEL#23.
21
(3)
True rms current meter SEL#42.
Local Area Data Channel (LADC) is a limited distance metallic facility provided by the
telephone company for data transmission. It may be either a two-wire or four-wire
nonloaded facility. Protection of these facilities consists of limiting the combined AC
and DC current during normal operation to a value consistent with CO protective
devices. Protection of network personnel is ensured by limiting the AC and DC voltages
at the network interfaces to levels permitted for non-hazardous voltage sources as
defined in ANSI/TIA-968-A subclause 4.4.3. If ringing is used, it is to meet the
requirements of ANSI/TIA-968-A subclause 4.4.4 (see subclause 8.8 for test
procedures)
To verify that the currents and voltages present at the interface are not hazardous to
personnel or equipment.
22
Note: Refer to subclause 5.5 for equipment details.
23
24
8.5.4 Equipment States Subject to Test
All operating states, except ringing.
25
26
27
28
29
30
8.5.5 Procedure
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
(1)
Place EUT in first operating state.
31
32
(2)
Connect current meter between T and R leads of the EUT, and measure combined
AC and DC short circuit current.
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2
(3)
Repeat Step (2) with current meter between T and ground and between R and
ground.
3
4
(4)
Repeat Step (1) through Step (3) for the T1 and R1 pair of the EUT if testing a fourwire interface.
5
(5)
Connect DC voltmeter between T and ground, and measure voltage.
6
(6)
Repeat Step (5) with voltmeter between R and ground.
7
(7)
Repeat Step (5) and Step (6) for the T1 and R1 pair if testing a four-wire interface.
8
9
(8)
Connect oscilloscope between T lead and ground, and measure AC peak and
combined AC peak and DC voltages with other network leads unterminated.
10
(9)
Repeat Step (8) with oscilloscope between R and ground.
11
(10)
Repeat Step (8) and Step (9) for the T1 and R1 pair if testing a four-wire interface.
12
13
(11)
Repeat Step (8) through Step (10) for AC peak voltage only with other network
leads individually terminated to ground.
14
(12)
Repeat Step (2) through Step (11) for other modes of operation.
15
16
17
8.5.6 Alternative Methods
18
19
20
8.5.7 Suggested Test Data
(1)
Current between conductor pairs (AC and DC).
21
(2)
Current between each conductor and ground (AC and DC).
22
(3)
DC voltages to ground for each conductor.
23
(4)
AC voltages to ground for each conductor (other conductors unterminated).
24
(5)
AC voltages to ground for each conductor (other conductors terminated).
25
26
(6)
AC plus DC (total) voltages to ground for each conductor (other conductors
unterminated).
None suggested.
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4
8.5.8 Comments
Refer to ANSI/TIA-968-A subclause 4.4.3 for the definition of non-hazardous voltage.
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8.6
Ringdown Voiceband Private Line and Metallic Channel Interface
ANSI/TIA-968-A, 4.4.1.7
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
8.6.1 Background
19
20
21
22
8.6.2 Purpose
23
24
25
8.6.3 Equipment
(1)
DC current meter SEL#19.
26
(2)
DC voltmeter SEL#22.
Voiceband private lines referred to in this requirement provide a dedicated voice
channel with signaling capability between two or more customer premises. The facility
may be either two-wire or four-wire and is usually referred to by the type of signaling
between locations (points). Thus, there are two-point and multipoint private lines. Twoway ringdown, or simply "ringdown," is one of the signaling methods used for such
private lines. The signaling range can be extended by converting to an inband signaling
tone referred to as single-frequency signaling. A metallic facility referred to in this
requirement is simply a pair or two pairs of wires with no restriction on the type of
signaling that can be used. Two-way ringdown relies solely on the application of ringing
voltage at either end of the private line for alerting the other end. Battery is not required
for voice transmission, but DC monitoring voltage, as defined in subclause 8.8.1, may
be present. The short circuit limit for both ringdown and metallic private lines is
consistent with the maximum current capabilities of most load coils that may be on the
line.
To verify that voltages and currents appearing at ringdown and metallic private line
interfaces are not hazardous to personnel or equipment.
27
28
Note: Refer to subclause 5.5 for equipment details.
29
30
31
8.6.4 Equipment States Subject to Test
(1)
Idle.
32
(2)
Talking.
33
(3)
Signaling.
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8.6.5 Procedure
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
Inspect appropriate circuit diagrams to verify the following:
(1)
Ringing voltage is applied to the R lead with the T lead grounded for two-wire
interfaces;
10
11
(2)
Ringing voltage is simplexed on the T and R leads, and ground is simplexed on the
T1 and R1 leads for four-wire interfaces.
12
13
(3)
Perform tests specified in subclause 8.8.5 to verify compliance with ringing source
requirements in the signaling state.
14
(4)
Place EUT in the idle state.
15
16
(5)
Connect DC voltmeter between T lead and ground of the EUT, and measure the
voltage, noting polarity.
17
(6)
Repeat Step (4) for R lead.
18
19
(7)
Repeat Step (4) and Step (5) for T1 and R1 leads of the EUT if testing a four-wire
interface.
20
(8)
Repeat Step (3) through Step (6) with EUT in the talking state.
21
(9)
Place EUT in idle state.
22
(10)
Connect current meter between T and R leads, and measure short circuit current.
23
(11)
Repeat Step (9) between T lead and ground and between R lead and ground.
24
(12)
Repeat Step (9) for T1 and R1 leads if testing a four-wire interface.
25
(13)
Repeat Step (9) through Step (11) for talking state.
26
27
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8.6.6 Alternative Methods
None suggested.
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8.6.7 Suggested Test Data
Brief written analysis of observed ringing circuit arrangements verifying the following: (i)
ringing is used for alerting only, (ii) ringing voltage is applied to R lead, and (iii) ringing
voltage is simplexed on T and R leads.
(1)
DC voltages during idle and talking states:
8
(a)
T to ground;
9
(b)
R to ground;
10
(c)
T1 to ground;
11
(d)
R1 to ground.
12
13
(2)
DC current during idle and talking states:
14
(a)
T to R;
15
(b)
T to ground;
16
(c)
R to ground;
17
(d)
T1 to R1;
18
(e)
T1 to ground;
19
(f)
R1 to ground.
20
21
22
23
8.6.8 Comments
Refer to ANSI/TIA-968-A subclause 4.4.3 for the definition of non-hazardous voltage.
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8.7
Physical Separation of Leads ANSI/TIA-968-A, 4.4.2
8.7.1 Background
Physical separation of leads within approved terminal equipment and protective circuitry
is part of the overall requirement that hazardous voltages can’t appear at the network
interface.
8
9
10
11
8.7.2 Purpose
12
13
14
8.7.3 Equipment
(1)
DC voltmeter SEL# 22 (if required).
15
(2)
True rms AC voltmeter SEL#41 (if required).
To verify that network interface leads are adequately separated from power leads and
from hazardous voltage leads that connect to non-approved equipment.
16
17
Note: Refer to subclause 5.5 for equipment details.
18
19
20
21
8.7.4 Equipment States Subject to Test
22
23
24
25
26
27
28
29
30
8.7.5 Procedure
Powered EUT connected to non-approved equipment, if non-approved equipment
provides a source of hazardous voltage.
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
(1)
31
32
33
Inspect schematic and/or wiring diagram to identify leads for connection to the
network interface, including telephone connections, auxiliary leads, and E&M leads.
Also identify power leads and leads to non-approved equipment that by the definition
provided in ANSI/TIA-968-A subclause 4.4.3, carry hazardous voltage.
Note: Leads in this procedure refer to any type of metallic connection.
(2)
Inspect the equipment to verify that leads for connection to the network are
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adequately separated from power leads and from leads to non-approved equipment
carrying hazardous voltage as follows: Leads for connection to the network are not
routed in the same cable as, or use the same connector as, leads or metallic paths
making power connections. Leads for connection to the network are not routed in
the same cable as, or use adjacent pins on the same connector as, leads to non–
approved equipment where those leads carry hazardous voltage.
(3)
Use the AC or DC voltmeter as required to confirm that the affected leads to nonapproved equipment are indeed hazardous.
9
10
11
8.7.6 Alternative Methods
12
13
14
8.7.7 Suggested Test Data
(1)
Provide a short discussion that summarizes observation of:
15
(2)
Lead separations.
16
(3)
Voltages on leads to non-approved equipment.
17
(4)
Lead routing in cables.
18
19
(5)
Pin assignments in connectors with leads for connection to both the network
interface and non-approved equipment.
20
21
22
23
24
25
26
8.7.8 Comments
None suggested.
The identification of non-hazardous voltage leads to non-approved equipment may be
verified by inspecting the circuit diagram or actual measurement as appropriate.
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8.8
Ringing Sources ANSI/TIA-968-A, 4.4.4
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
8.8.1 Background
24
25
26
8.8.2 Purpose
27
28
29
8.8.3 Equipment
(1)
Digital sampling storage oscilloscope SEL#23.
30
(2)
Frequency counter SEL#26.
A ringing source is considered to be non-hazardous to telephone company personnel if
it meets the current, voltage, and duration requirements in subclause 4.4.4 of ANSI/TIA968-A. The requirements take into account wet hands-to-feet contact and wet hand-tohand contact. Current values up to 100 mA peak-to-peak are permitted for a period of
5 seconds after which a silent (no ringing) interval of at least 1 second is required to
permit "let-go." During the first second of a five-second ringing interval, current values
up to 600 mA are permitted, based upon the time required to trip (stop) the ringing after
contact with the 500-ohm and 1500-ohm resistances. In general, the current limit
decreases from 600 mA peak-to-peak to 100 mA peak-to-peak, with increasing trip
times of up to 1 second, as depicted in Figure 4.4 of ANSI/TIA-968-A. A monitoring
voltage may be used in place of, or in addition to, the trip device depending on the
values of current through 500-ohm and 1500-ohm resistances. A trip device may be
sensitive to either DC or AC current or both, but in any case the ringing source is
disconnected when the AC current reaches a predetermined value. Monitoring voltage
is a DC voltage that is applied by the EUT during the one-second silent interval to warn
people contacting the pair that a ringing source may be connected at any time. It is
limited to a range of 19 V (the lower limit of a 24-volt battery) to 56.5 V (the upper limit
of a 48-volt battery). The 200 V peak-to-ground limit allows for a maximum DC
component of 50 V when used in conjunction with the maximum 300 V peak-to-peak
limit.
To verify the EUT ringing source characteristics.
31
32
Note: Refer to subclause 5.5 for equipment details.
33
34
35
36
8.8.4 Equipment States Subject to Test
There are two operating states: ringing and non-ringing. All measurements except for
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monitoring voltage are made in the ringing state. Monitoring voltage, when required, is
measured in both states.
3
4
5
6
7
8
9
8.8.5 Procedure
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
(1)
Connect the frequency counter to the T and R leads of the EUT, and measure the
frequency of the ringing voltage.
10
11
12
(2)
If the EUT is a four-wire device, connect the frequency counter to the T and R leads
of the EUT tied together and to the T1 and R1 leads of the EUT also tied together,
and measure the frequency of the ringing voltage.
13
14
(3)
Connect the EUT to the test circuit of Figure 8.8-1 if the EUT is a two-wire device, or
to the test circuit of Figure 8.8-2 if the EUT is a four-wire device.
15
16
17
Note: A 10X probe should be used.
(4)
Set switch S1 to position "A" and measure:
18
19
(a)
peak-to-peak ringing voltage;
20
(b)
peak-to-ground ringing voltage;
21
(c)
ringing time interval;
22
(d)
non-ringing time interval.
23
24
(5)
Set switch S1 to position "B" and initiate ringing.
25
(6)
Measure and record the peak-to-peak voltage.
26
(7)
If ringing is tripped, measure duration of applied ringing.
27
(8)
Convert the voltage recorded in Step (6) to peak-to-peak current in milliamperes.
28
(9)
Set switch S1 to position "C" and repeat Step (5) through Step (8).
29
(10)
Refer to the table in Figure 8.8-3 to determine compliance with ringing voltage and
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the need for a tripping device and a monitoring voltage.
2
3
4
5
6
Note: The peak-to-peak current and the time duration of the current measured through the 500-ohm
and 1500-ohm resistors in Step (5) through Step (9) are used in this determination. If a
monitoring voltage is required, connect the oscilloscope (DC coupled) using the 10X probe and
measure the DC voltage present during the ringing and non-ringing states.
7
8
9
8.8.6 Alternative Methods
10
11
12
8.8.7 Suggested Test Data
(1)
Ringing frequency.
13
(2)
Ringing voltages, peak-to-peak and peak-to-ground.
14
(3)
Duration of the ringing interval.
15
(4)
Duration of the non-ringing interval.
16
(5)
Current through 500-ohm resistance and trip time, if required.
17
(6)
Current through 1500-ohm resistance and trip time, if required.
18
(7)
Monitor voltage, if required.
19
20
21
8.8.8 Comments
None suggested.
Refer to ANSI/TIA-968-A subclause 4.4.3 for the definition of non-hazardous voltage.
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2
3
4
5
6
7
Note: A 10X probe is normally used to obtain the reading. The input Impedance of the probe should
be equal to or greater than 1 megohm.
Figure 8.8-1 Ringing Sources, Two-Wire
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2
3
4
5
6
7
8
Note: A 10X probe is normally used to obtain the reading. The input impedance of the probe should
be equal to or greater than 1 megohm.
Figure 8.8-2 Ringing Sources, Four-Wire
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2
3
4
5
6
7
8
Figure 8.8-3 Ringing Protection
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8.9
Intentional Operational Paths to Ground ANSI/TIA-968-A, 4.4.5.1
2
3
4
5
6
7
8
8.9.1 Background
Products which have intentional DC current paths to ground will not comply with the
leakage current limitations of ANSI/TIA-968-A, 4.3. To ensure that these network
connections do not pose a hazard to network personnel, a ground continuity test is
performed from leakage exempted network points to earth ground connections.
9
10
11
12
13
14
15
16
17
18
The Tip Ground state of a central office implemented telephone is a momentary state
(200 to 1200 ms). It occurs when (1) a coin is in the hopper and (2) the network is
making an initial coin deposit test, a local coin overtime deposit test, or stuck coin test,
and when the network is trying to collect or return a coin. When the network performs
those operations, it opens the ring conductor and places a DC voltage (typically -48,
+48, -130, or +130 Vdc) on the tip conductor. The central office implemented telephone
has a reset electromagnet in series with a coin relay (900 to 2000 ohms) between the
tip conductor at the network interface and the earth grounding connection. This test is
performed on the grounded side of the coin relay.
19
20
21
22
8.9.2 Purpose
23
24
25
8.9.3 Equipment
(1)
Variable DC current source SEL#17.
26
(2)
DC current meter SEL#19.
27
(3)
DC volt meter SEL#22.
28
29
30
31
32
33
34
35
To verify the ground continuity between grounded telecommunications points and EUT
earth grounding connections.
Note: Refer to subclause 5.5 for equipment details.
8.9.4 Equipment States Subject to Test
Test all telephone connections including tip, ring, tip1, ring1, E&M leads, and auxiliary
leads to earth grounding connections. In the event that there is a circuit or component
between the network demarcation point and ground, the test is to be performed from the
grounded side of the component or circuit.
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2
3
4
5
6
7
8.9.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 8.9-1.
8
(2)
Select the appropriate EUT test points.
9
10
(3)
Gradually increase the current from zero to 1 A, then maintain the 1 A current for one
minute.
11
12
(4)
Monitor the voltage on the DC voltmeter. Verify that the voltage does not exceed 0.1
Volt at any time.
13
14
15
8.9.6 Alternative Methods
16
17
18
8.9.7 Suggested Test Data
(1)
List of test points.
19
(2)
Maximum DC voltage measured during tests.
20
21
22
23
24
8.9.8 Comments
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
None suggested.
Refer to subclause 4.4 of ANSI/TIA-968-A for the definition of a non-hazardous voltage
source.
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2
3
4
5
6
7
8
Note A - See 7.3.1.3
Figure 8.9-1 Intentional Operational Paths to ground
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8.10 Intentional Protective Paths to Ground ANSI/TIA-968-A, 4.4.5.2
2
3
4
5
6
7
8
9
8.10.1 Background
Products which have intentional DC conducting paths to ground for protection purposes
may fail the leakage current limitations of ANSI/TIA-968-A, 4.3. The leakage current
test of clause 7 allows these paths to be opened (or component removed). To ensure
that these network connections do not present a hazard to network personnel, the
components are re-installed, and a leakage current test is performed at a lower voltage
representative of an AC power fault.
10
11
12
13
8.10.2 Purpose
14
15
16
8.10.3 Equipment
(1)
Variable AC voltage source SEL#43 (for TE) or SEL#44 (for PC).
17
(2)
AC current meter SEL#42.
To verify that protective devices do not provide a path for harmful leakage currents at
AC power voltages.
18
19
Note: Refer to subclause 5.5 for equipment details.
20
21
22
23
8.10.4 Equipment States Subject to Test
24
25
26
27
28
29
8.10.5 Procedure
(1)
Re-install any protective devices removed for the leakage tests (See clause 7).
30
(2)
Connect the EUT to the test circuit of Figure 8.10-1.
31
(3)
Select the appropriate EUT test points.
32
(4)
Gradually increase the voltage from zero to 120 VRMS (for TE) or 300 VRMS (for
Simplexed telephone connections, including tip and ring, tip1, ring1, E&M leads, and
auxiliary leads.
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
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PC). Maintain the maximum voltage for one minute.
2
3
(5)
Monitor the current through the AC ammeter. Verify that the current does not exceed
10 mA peak at any time.
4
5
6
8.10.6 Alternative Methods
7
8
9
8.10.7 Suggested Test Data
None suggested.
(1)
List of leads tested.
10
(2)
List of maximum current measured for each combination.
11
12
13
14
15
16
17
8.10.8 Comments
(1)
This test is to be applied to leads excluded from the requirements of ANSI/TIA-968A, 4.4.5.1 that contain only intentional protective paths to ground. An EUT which has
both intentional operational and intentional protective paths to ground needs to meet
only the requirements of ANSI/TIA-968-A, 4.4.5.1 referred to in subclause 8.9 of this
Document
18
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Refer to ANSI/TIA-968-A, 4.4.3 for the definition of a non-hazardous voltage source and
ANSI/TIA-968-A, 4.3 Note (1).
Figure 8.10-1 Intentional Protective Paths to Ground
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
9
SIGNAL POWER LIMITATIONS ANSI/TIA-968-A, 4.5
9.1
Voiceband Signal Power – Not Network Control signals ANSI/TIA-968-A,
4.5.2.1.1
9.1.1 Background
There are seven different service-specific power criteria covered for analog voiceband
internal signal sources. The services include connections to:
-
PSTN;
foreign exchange;
tie trunks;
off-premises stations;
test equipment;
private lines using ringdown or inband signaling.
Maximum voiceband signal power criteria are based on multichannel analog carrier
overload characteristics and intermodulation distortion limits. Each specific type of
service has a different maximum limit which takes into account, among other factors:
the multichannel carrier overload limit;
the multichannel carrier activity factor per channel;
the average input signal power per channel;
the maximum input signal power per channel;
the local exchange facility attenuation characteristic;
the type of signal being transmitted.
These restrictions ensure that equipment will not apply a signal to the multichannel
carrier in excess of the maximum level permitted per channel if it encounters a low loss
loop facility. The signal power limit specified for voiceband signals applies to all internal
signals other than live-voice. Live-voice limits are not specified because normal
statistical variations among talkers will tend to produce appropriate average talker
power per channel at the multichannel carrier interface. Also, loud talkers will lower their
talking levels because of excessive side tone levels or if requested by the other
connected parties, thus providing a form of self-correction for excessive live-voice signal
power. Such factors and controls do not apply for other than live-voice signals, and
thus the limitations apply. The 3-second averaging time approximates the period
necessary for a listener to perceive interference as intelligible crosstalk.
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2
3
4
5
6
9.1.2 Purpose
7
8
9
9.1.3 Equipment
To verify that the voiceband signal power from internal sources, other than live-voice
signals, transmitted to the PSTN, are properly limited.
(1)
Applicable loop simulator SEL#4.
10
(2)
Bandpass filter SEL#5
11
(3)
DC current meter SEL#19.
12
(4)
True rms AC voltmeter SEL#40.
13
(5) Signal Analyzer (FFT) SEL#56
14
15
Note: Refer to subclause 5.5 for equipment details.
16
17
18
19
20
21
22
9.1.4 Equipment States Subject to Test
23
24
25
26
9.1.5 Procedure
(1)
Connect the EUT to the applicable test circuit of Figure 9.1-1 through Figure 9.1-3
using the 200 Hz to 4000 Hz bandpass filter and voltmeter.
27
28
(2)
Place the EUT in the desired off-hook state and transmit a desired signal from
internal sources at maximum power.
29
30
(3)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
Test any off-hook state of the EUT which transmits signals to the network which are not
intended for network control. For an EUT that does not normally transmit signals toward
the network interface in the off-hook state, the idle (nontransmitting) state is to be
tested. For data signals, the EUT is tested in accordance with subclause 8.4.
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(4)
Repeat step (2) and step (3) for other internal signals.
2
(5)
Repeat step (2) through step (4) for other operating states, if applicable.
3
4
5
6
7
9.1.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 9.1-1 through Figure 9.1-3 and replace
the bandpass filter and true rms AC voltmeter with the signal analyzer SEL#56.
8
(2)
Set the signal analyzer to measure the following:
9
(a)
Signal level in dBm, 600 ohms.
10
(b)
Averaging over 3 second.
11
(c)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
12
Note: If the Signal Analyzer does not provide a balanced input an isolation transformer may be used.
13
14
15
(3)
Place the EUT in the desired off-hook state and transmit a desired signal from
internal sources at maximum power.
16
17
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
18
(5)
Repeat step (2) and step (3) for other internal signals.
19
(6)
Repeat step (2) through step (4) for other operating states, if applicable.
20
21
22
23
9.1.7 Suggested Test Data
(1)
Operating states.
24
(2)
Signals measured.
25
(3)
Signal power levels in dBm.
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(4)
Loop conditions for maximum signal power if appropriate.
2
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2
3
4
9.1.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
5
6
(2)
A sound attenuating cover should be placed on any acoustic pick-up device to
minimize the effects of ambient noise.
7
8
9
10
(3)
As mentioned in subclause 9.1.1, the level of live-voice signals are not regulated
under 47 CFR Part 68. Recorded or synthesized signals are not live-voice signals
and, as such, are regulated by 47 CFR Part 68. Typically there are three types of
signals to consider:
11
12
13
14
15
16
(a)
17
18
19
20
21
22
23
(b)
24
25
(c)
Electrical signals recorded at a given network interface.
The test signal used is to be the one that results in the highest output signal
level when played back to the line. The level of the output signal measured
should not exceed the specified limit for that class of service (e.g., -9 dBm for
PSTN ports).
Acoustic signals recorded locally.
These signals may be recorded by means of an integrated or external
microphone. The test signal is to be recorded with an acoustic input signal level
that results in the highest output signal level when played back to the line. The
level of the output signal measured should not exceed the specified limit for that
class of service (e.g., -9 dBm for PSTN ports).
Signals recorded elsewhere (e.g. electronic “wave” files contained in voice
servers).
26
27
28
29
30

If the recorded signal is not under the control of the EUT manufacturer (e.g.
“wave” files from the Internet) then the EUT is to limit the output signal level
to not exceed the specified limit for that class of service (e.g., -9 dBm for
PSTN ports). The test signal used is to be the one that results in the highest
output signal level when played back to the line.
31
32
33
34

If the recorded signal is under the control of the EUT manufacturer (directly
or indirectly) then the EUT is to be tested with these recorded signals and
the output signal level is not to exceed the specified limit for that class of
service (e.g., -9 dBm for PSTN ports).
35
The test signal used may depend on
the EUT. Possible signals include, but are
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2
3
4
5
6
not limited to, a 1 kHz tone, white noise, or a modulated multifrequency signal. The
level of this signal should be taken over a 3 second average.
(4)
A voltmeter with an averaging time less than 3 seconds may be used. In this case
correction factors should be applied to the measured value based on the duty cycle
of the signals.
7
(5)
The insertion loss of the bandpass filters used is to be taken into account.
8
9
(6)
The insertion loss of any balanced to unbalanced transformer used is to be taken into
account.
10
11
12
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
13
14
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
15
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
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2
3
4
Refer to the figures of clause 1 of ANSI/TIA-968-A.
Figure 9.1-1. Voiceband Signal Power, Two-Wire
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2
3
4
5
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
6
7
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
8
9
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
12
Figure 9.1-2. Voiceband Signal Power, Four-Wire
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2
3
4
5
6
7
8
Note: The condition shown is for a four-wire interface; for two-wire interface, the T1 and R1 is not
present.
Figure 9.1-3. Voiceband Signal Power, E&M Tie
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9.2
Voiceband Signal Power - Network Control Signals ANSI/TIA-968-A, 4.5.2.1.2
2
3
4
5
6
7
8
9
10
11
12
13
14
15
9.2.1 Background
16
17
18
19
20
21
22
Under certain conditions, central office implemented telephones generate coin deposit
signals in response to coins being deposited. These signals are a discrete number of
bursts of a two-frequency tone and are intended to be detected by network elements.
Excessive coin deposit signals may harm the network. Therefore, they are subject to
clause 4.5.2.1.2 of ANSI/TIA-968-A although they are not specifically mentioned by
name.
23
24
25
26
9.2.2 Purpose
27
28
29
9.2.3 Equipment
(1)
Applicable loop simulator SEL#4.
30
(2)
Bandpass filter SEL#5.
31
(3)
DC current meter SEL#19.
32
(4)
True rms AC voltmeter SEL#40.
33
34
The signal power limitations for network control signals minimize interference to other
users of the PSTN. These limitations are based on the cable wire-pair crosstalk
characteristics in the local exchange network and the interfering effect that such signals
cause to third party users of network services throughout the cable-wire facilities.
Multichannel carrier input overload is not a factor in this situation since network control
signals terminate in the local CO. At the present time, the effect of DTMF tones is
disregarded when they are generated by manual operation of a telephone keypad or are
generated automatically with no more than 40 DTMF digits per keystroke and are used
for purposes of transmitting information after the establishment of an end-to-end
connection. The subscriber line carrier system's susceptibility is not a factor either since
it operates above the voiceband.
To verify that the level of any signal primarily intended for network control is properly
limited.
Note: Refer to subclause 5.5 for equipment details.
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4
5
9.2.4 Equipment States Subject to Test
6
7
8
9
9.2.5 Procedure
Test any off-hook states of the EUT which transmit to the network signals primarily
intended for network control.
(1)
Connect the EUT to the appropriate test circuit of Figure 9.2-1 or Figure 9.2-2 using
the bandpass filter and voltmeter.
10
(2)
Set the voltmeter to measure the signal level in dBm.
11
(3)
Place the EUT in the off-hook state and transmit a desired network control signal.
13
14
(4)
and record the maximum signal power level in dBm at minimum and maximum loop
currents attainable with the loop simulator, if applicable.
15
16
(5)
Repeat step (3) and step (4) for other network control signals, if applicable (e.g.
other DTMF digits, MF digits or coin deposit signals).
17
(6)
Repeat step (3) and step (4) for other operating states, if applicable.
18
19
20
21
9.2.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 9.2-1 through Figure 9.2-2 and replace
the bandpass filter and true rms AC voltmeter with a signal analyzer (SEL 56).
22
(2)
Set the signal analyzer to measure the following:
12
23
(d)
Signal level in dBm, 600 ohms.
24
(e)
Averaging over 3 second.
25
(f)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
26
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
27
28
(3)
Place the EUT in the desired off-hook state and transmit a desired Network Control
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signal.
2
3
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
4
5
(5)
Repeat step (2) through step (4) for other network control signals, if applicable (e.g.
other DTMF digits, MF digits or coin deposit signals).
6
(6)
Repeat step (2) through step (4) for other operating states, if applicable.
7
8
9
10
9.2.7 Suggested Test Data
(1)
Operating states.
11
(2)
Network Control Signal.
12
(2)
Signal power levels in dBm.
13
(3)
Loop conditions for maximum signal power, if appropriate.
14
15
16
17
9.2.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
18
19
(2)
For EUT using manual DTMF signaling, the signal level should be measured for
each digit and the one having the maximum power should be reported.
20
21
(3)
For EUT using manual DTMF signaling, a duty cycle of 40% is assumed. Thus
reduce the measured level by 4dB.
22
23
(4)
For EUT using automatic DTMF signaling, the sequence of numbers should use all
digits and be of maximum address length.
24
(5)
No measurements are required for DC pulse dialing.
25
26
27
(6)
A voltmeter with an averaging time less than 3 seconds may be used. In this case
correction factors should be applied to the measured signal power based on the
duty cycle.
28
(7)
Insertion loss of bandpass filter
should be taken into account.
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2
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2
3
4
5
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
6
7
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
8
9
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
Figure 9.2-1. Network Control Signal Power, Two-Wire
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2
3
4
5
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
6
7
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
8
9
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
12
Figure 9.2-2. Network Control Signal Power, Four-Wire
13
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4
9.3
Through-Transmission Equipment – DC Conditions for On-Premises
ANSI/TIA-968-A, 4.5.2.3.1
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
9.3.1 Background
29
30
31
32
9.3.2 Purpose
33
34
35
9.3.3 Equipment
(1)
DC voltmeter SEL#22.
36
(2)
DC current meter SEL#19.
37
Through-transmission equipment may provide DC for powering attached equipment.
The attached equipment would be approved separately. To ensure compliance with
signal power limits of ANSI/TIA-968-A, the DC conditions provided to the attached
equipment are required to fall within the range of conditions it would normally encounter
if connected directly to the PSTN. When checking for compliance take the range of
resistances presented by the attached equipment and the wiring that may be used to
connect it into account.
The maximum open circuit voltage provided by the loop simulator circuit shown in
Figure 1.1 of ANSI/TIA-968-A is 56.5 V. The maximum short circuit current is 141.25
mA, but 140 mA is used for this value in other places (e.g., see 4.5.2.7.2.2 of ANSI/TIA968-A). With an allowance of up to 400 ohms for the resistance of the attached
equipment, the minimum current that will flow is 19.86 mA, but 20 mA is used for this
value in other places (e.g., see 4.5.2.7.2.3 of ANSI/TIA-968-A).
The minimum current test condition is based on the criteria in the network interface
standard T1.401. It allows a total resistance of 430 ohms for the customer installation,
which consists of 400 ohms for the terminal equipment plus an allowance of 30 ohms
for wiring and series devices between the terminal equipment and the network interface.
If the EUT is designed to provide support for an external resistance greater than 430
ohms, it should be tested with that external resistance.
To verify that the DC conditions provided by the EUT meet the limits for the loop
conditions that terminal equipment expects to encounter.
Note: Refer to subclause 5.5 for equipment details.
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2
3
9.3.4 Equipment States Subject to Test
4
5
6
9.3.5 Procedure
(1)
Configure the EUT for normal operation.
7
8
(2)
Measure and record the open circuit voltage provided for powering the attached
equipment.
9
(3)
Connect the EUT to the test circuit of Figure 9.3-1.
10
11
(4)
Adjust RL to 0 ohms, creating a short circuit across the through-transmission port of
the EUT; measure and record the current that flows.
12
13
(5)
Adjust RL to 430 ohms or to the maximum external resistance supported by the EUT,
if greater; measure and record the current that flows.
Idle and Active state.
14
15
16
17
18
9.3.6 Alternative Methods
19
20
21
9.3.7 Suggested Test Data
(1)
The open circuit voltage.
22
(2)
Short circuit current.
23
(3)
Maximum external resistance supported by the EUT if greater than 430 ohms.
24
25
(4)
Current at 430 ohms or at the maximum external resistance supported by the EUT, if
greater than 430 ohms.
None suggested.
26
27
28
29
30
9.3.8 Comments
If the test current meter does not incorporate internal fuse protection, a fuse should be
added to the test circuit. The purpose of this fuse is to protect the test instrument if the DC
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source of the EUT through-path does not have adequate current limiting.
Tip
EUT
Ring
4
5
6
7
8
9
Port for
Thru Xmission
2
3
A
Figure 9.3-1. DC Conditions for Through Transmission
104
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1
9.4
2
3
4
5
6
7
8
9
9.4.1 Background
EUTs with through-transmission paths that may be connected to data equipment is not
to use the fixed loss loop or programmed data jack configurations unless they are
approved in accordance with Section 4.5.2.4 of ANSI/TIA-968-A. The rule restricts the
use of the fixed loss loop and programmed data jack configurations. These jack
configurations are to be used only on equipment specifically designed for data signals
with power levels that comply with Section 4.5.2.4 of ANSI/TIA-968-A.
10
11
12
13
9.4.2 Purpose
14
15
16
9.4.3 Equipment
17
18
19
9.4.4 Equipment States Subject to Test
20
21
22
9.4.5 Procedure
23
24
Verify that the equipment is not equipped with either the universal or programmed data
jack configuration.
25
26
27
9.4.6 Alternative Methods
28
29
30
31
9.4.7 Suggested Test Data
To verify that the EUT or protective circuit is not equipped with the universal or
programmed data jack configurations.
Schematics, and/or installation manuals.
Not applicable.
Inspect the EUT, its schematics, and/or installation manual.
None suggested.
Statement that the equipment is not equipped with the universal of programmed data jack
features.
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9.4.8 Comments
2
3
None.
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2
9.5
Voiceband Signal Power - Data ANSI/TIA-968-A, 4.5.2.4
3
4
5
6
7
8
9
10
9.5.1 Background
11
12
13
9.5.2 Purpose
14
15
16
9.5.3 Equipment
(1)
Applicable loop simulator SEL# 4.
17
(2)
Bandpass filter SEL#5.
18
(3)
DC current meter SEL#19.
19
(4)
True rms AC voltmeter SEL#40.
The fixed loss loop, programmed and permissive jack configuration for approved data
equipment with through-transmission paths permit users to operate their data
equipment at maximum usable signal power in the PSTN. In the fixed loss loop and
programmed jack configurations, the telephone company controls the loss. The signal
power level for a permissive jack configuration is based upon a non-adjustable level that
is equivalent to other than live-voice signal power levels.
To verify that the data signal power level transmitted to the PSTN is properly limited.
20
Note: Refer to subclause 5.5 for equipment details.
21
22
23
9.5.4 Equipment States Subject To Test
24
25
26
27
9.5.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.5-1 using one of the EUT's specified
jack configurations and using the bandpass filter and voltmeter.
28
(2)
Set the voltmeter to measure the signal level in dBm.
29
(3)
Place the EUT in the off-hook state and cause it to transmit a desired data signal.
30
(4)
Measure and record the maximum signal power level in dBm at minimum and
Any off-hook state in which data is transmitted to the PSTN.
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maximum loop currents attainable with the loop simulator, if applicable.
2
(5)
Repeat step (3) and step (4) for the other data signals, if applicable.
3
(6)
Repeat step (3) and step (4) for the other operating states, if applicable.
4
(7)
Repeat step (3) and step (4) for other specified jack configurations, if applicable.
5
6
7
Note: If the EUT is equipped with a programmable jack configuration, perform step (1) through step
(5) for all specified values of the programming resistor, RP.
8
9
10
11
12
9.5.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 9.5-1 and replace the bandpass filter
and true rms AC voltmeter with a signal analyzer (SEL XX).
13
(2)
Set the signal analyzer to measure the following:
14
(g)
Signal level in dBm, 600 ohms.
15
(h)
Averaging over 3 second.
16
(i)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
17
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
18
19
(3)
Place the EUT in the desired off-hook state and transmit a desired data signal.
20
21
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
22
(5)
Repeat step (2) through step (4) for other data signals, if applicable.
23
(6)
Repeat step (2) through step (4) for other operating states, if applicable.
24
(7)
Repeat step (2) through step (4) for other specified jack configurations, if applicable.
25
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2
3
4
9.5.7 Suggested Test Data
(1)
Jack configurations.
5
(2)
Data signals.
6
(3)
Operating states.
7
(4)
Signal power levels in dBm.
8
(5)
Loop conditions for maximum signal power, if appropriate.
9
10
11
12
9.5.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
13
(2)
The insertion loss of bandpass filter should be taken into account.
14
(3)
For network control signals, see subclause 8.2.
15
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2
3
4
5
Note 1.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
6
7
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
8
9
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
12
13
Note 4.
For programmed data equipment, measurements should be made with the value of the
programming resistor (RP) set for each of the following value: short circuit, 150 ohms,
336 ohms, 569 ohms, 866 ohms, 1240 ohms, 1780 ohms, 2520 ohms, 3610 ohms,
5490 ohms, 9200 ohms, 19800 ohms, and open circuit.
14
15
16
17
Figure 9.5-1. Voiceband Signal Power, Data, TE
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9.6
Through-Transmission – Port to Port Amplification ANSI/TIA-968-A, 4.5.2.5.1
2
3
4
5
6
7
8
9
10
11
9.6.1 Background
12
13
14
15
9.6.2 Purpose
16
17
18
9.6.3 Equipment
19
(2) Bandpass filter SEL#14.
20
(3) Multiplexer/demultiplexer with zero level encoder/decoder SEL#32.
21
(4) True rms AC voltmeter SEL#40.
22
(5) White noise generator SEL#45.
23
Terminal equipment with through transmission provisions between network ports is
required to limit the net amplification between ports in accordance with the matrix shown
in ANSI/TIA-968-A subclause 4.5.2.5.1. The values given in the matrix ensure that the
maximum permissible signal power levels at the network interface are not exceeded for
any through path. In the case of digital port connections, the net amplification refers to
the analog equivalent level. When 1.544 Mb/s connections are involved for both ports
in question, then the through gain applies for each of the subrate channels when
converted to analog through a zero-level decoder.
To verify that the through-transmission connections of the EUT do not provide gain in
excess of that permitted in the matrix.
(1) Applicable loop simulator SEL#4.
Note: Refer to subclause 5.5 suggested equipment list (SEL) for equipment details.
24
25
26
9.6.4 Equipment States Subject to Test
27
28
29
30
31
32
9.6.5 Procedure
Off-hook states with connection for through transmission.
In those cases where the interface impedances are not evident from the information
provided, the tester is to contact the designer and request this information be provided
so appropriate correction factors can be calculated for the through-transmission loss
measurements.
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2
3
4
5
6
(1) Connect analog EUT to the test circuit of Figure 9.6-1 and establish connection
between the ports under test for minimum current condition of each port as applicable.
Otherwise, connect digital EUT, with through ports embedded in 1.544 Mb/s system, to
the test circuits of Figure 9.6-2 and Figure 9.6-3. Establish a connection between the
ports under test.
7
8
(2) Set switch S1 to position "A." Adjust the filter to pass the band of frequencies below
3995 Hz.
9
Note 1.
If the EUT is band limited, then an appropriate filter adjustment is to be made.
10
11
(3) Establish a through-transmission connection in the direction of the network interface
under test.
12
13
(4) Set the output level of the white noise generator so that the voltmeter indicates (-11)
dBV. Maintain this level for all tests.
14
15
(5) Set switch S1 to position "B" and measure the signal present at the output side of the
EUT.
16
17
(6) Calculate the gain of the through-transmission path from the input level set in step (4)
and the output level measured in step (5).
18
19
(7) Repeat step (1) through step (6) for the opposite direction of transmission of the EUT, if
applicable.
20
(8) Repeat step (2) through step (7) for each of the following conditions as applicable:
21
(9) Minimum current through EUT input and maximum current through EUT output;
22
(10)
Maximum current through EUT input and maximum current through EUT output;
23
(11)
Maximum current through EUT input and minimum current through EUT output.
24
25
26
9.6.6 Alternative Methods
27
28
29
9.6.7 Suggested Test Data
A discrete or swept frequency method may also be used.
(1) Through-transmission paths.
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(2) Signal output levels from the EUT.
2
(3) Calculated net amplification or loss, and associated frequency.
3
4
5
6
7
9.6.8 Comments
8
9
10
(1) The net amplification may exceed the limit provided the absolute signal power levels
specified in ANSI/TIA-968-A subclause 4.5 for the interfaces in question are not
exceeded.
(2) If a swept frequency method is used, gain ripples in the passband may occur if an
impedance mismatch exists between the EUT and the source, or between the EUT
and the measuring device.
11
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2
True
RMS
Voltmeter
A
B
S1
A
Loop Simulator
(Notes 1 & 2)
B
Loop Simulator
(Notes 1 & 2 & 4)
EUT
Bandpass Filter
(Note 3)
White Noise Source
3
4
5
6
7
Note 1.
Select the appropriate loop simulator, holding circuit, or termination for the interface of the
EUT. Refer to the figures of clause 1 of ANSI/TIA-968-A.
8
9
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
12
Note 3.
The output impedance of the signal source should be such that, in combination with or in
place of R1 of the two-wire loop simulator circuit, the source impedance is either 600
ohms or matches the circuit of ANSI/TIA-968-A Figure 1.8.
13
14
Note 4.
The resistor R1 of the loop simulator may be replaced with the circuit of Figure 1.8 even
though other subclauses of ANSI/TIA-968-A specifies 600 ohms (e.g. Table 4.6, Note 1).
15
Figure 9.6-1 Through Transmission, Analog
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True
RMS
Voltmeter
A
B
S1
A
Loop Simulator
(Notes 1 & 2)
B
Figure 9.6-3
Loop Simulator
(Notes 1 & 2 & 4)
Bandpass Filter
(Note 3)
White Noise Source
1
2
3
4
Note 1.
Select the appropriate loop simulator, holding circuit, or termination for the interface of the
EUT.
5
6
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
7
8
9
Note 3.
The output impedance of the signal source should be such that, in combination with or in
place of R1 of the two-wire loop simulator circuit, the source impedance is either 600
ohms or matches the circuit of ANSI/TIA-968-A Figure 1.8.
10
11
Note 4.
The resistor R1 of the loop simulator may be replaced with the circuit of Figure 1.8 even
though other subclauses of ANSI/TIA-968-A specifies 600 ohms (e.g. Table 4.6, Note 1).
12
13
14
Figure 9.6-2. Through Transmission, Digital
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2
3
4
5
6
7
Figure 9.6-3. Digital EUT Arrangement for Figure 9.6-2
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9.7
Through-Transmission - SF Cutoff ANSI/TIA-968-A, 4.5.2.5.1(7)
2
3
4
5
6
7
8
9
9.7.1 Background
The single frequency (SF) cutoff limitations in this subclause apply only when the EUT
has a through path connecting either voiceband private lines, channels, or voiceband
metallic channels to other network interfaces. This limitation ensures that no signals
containing energy primarily in the SF band are transmitted across the network
interfaces. The comparator in the network's SF signaling circuitry will not activate on SF
signal bursts of 20 ms or less.
10
11
12
13
14
9.7.2 Purpose
15
16
17
9.7.3 Equipment
18
(2) Bandpass filter SEL#6.
19
(3) Digital sampling storage oscilloscope SEL#23.
20
(4) Frequency generator SEL#27.
21
(5) Multiplexer/demultiplexer SEL#32.
22
(6) Summing network SEL#35.
23
(7) True rms AC voltmeter SEL#40.
24
(8) White noise generator SEL#45.
25
To verify that signals in the 2450 Hz to 2750 Hz band are not transmitted into the
network facility unless there is at least an equal amount of energy in the 800 Hz to 2450
Hz band within 20 ms of application of signal.
(1) Applicable loop simulator SEL#4.
Note: Refer to subclause 5.5 for equipment details.
26
27
28
9.7.4 Equipment States Subject to Test
29
30
9.7.5 Procedure
Off-hook states with connection for through transmission.
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2
(1) Connect the EUT to the test circuit of Figure 9.7-1. Establish a connection between the
ports under test.
3
(2) Set switch S1 to position "A" and switch S2 to position "B."
4
(3) Adjust the output level of the white noise generator to read -15 dBV on the voltmeter.
5
(4) Set switch S1 to position "B" and switch S2 to position "A."
6
(5) Adjust the output of the frequency generator to read -14 dBV on the voltmeter.
7
8
(6) Set switch S1 to position "A," and measure on the oscilloscope time between the
switch closure and the moment of signal cutoff.
9
10
11
9.7.6 Alternative Methods
12
13
14
9.7.7 Suggested Test Data
15
(2) Length of time interval when the EUT stops through transmission.
16
17
18
19
9.7.8 Comments
None suggested.
(1) Through-transmission paths.
None.
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2
3
4
5
6
7
Note 1.
Select the appropriate loop simulator, holding circuit, or termination for the interface of the
EUT. For digital interfaces, use a mux/demux and zero-level decoder or companion
terminal equipment.
8
9
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
Note 3.
The resistor R1 of the loop simulator may be replaced with the circuit of ANSI/TIA-968-A
Figures 1.8.
12
13
Figure 9.7-1. Single Frequency Cut-off
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2
3
4
5
6
7
8
9
9.8
Through-Transmission - SF/Guard Bands ANSI/TIA-968-A, 4.5.2.5.2
9.8.1 Background
EUT can provide a transmission path that connects together two or more network
facilities. The purpose of the SF/guard band limitations in this subclause is to ensure
that a signal passing through the EUT will not be incorrectly interpreted as the SF
signal.
10
11
12
13
14
9.8.2 Purpose
15
16
17
9.8.3 Equipment
18
(2) Frequency generator SEL#27.
19
(3) Multiplexer/demultiplexer SEL#32 (if required).
20
(4) True rms voltmeter SEL#40.
To compare the insertion loss for analog and digital equipment in the 800 Hz to 2450 Hz
band to the insertion loss in the 2450 Hz to 2750 Hz band.
(1) Applicable loop simulator SEL#4.
21
22
Note: Refer to subclause 5.5 for equipment details.
23
24
25
26
27
28
9.8.4 Equipment States Subject to Test
29
30
31
32
33
9.8.5 Procedure
Operating state where a through connection is established between the two EUT ports
under test.
(1)
Connect analog EUT to the test circuit of Figure 9.8-1 and establish connection
between the ports under test for minimum current condition of each port as
applicable. Otherwise, connect digital EUT, with through ports imbedded in 1.544
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2
Mb/s systems, to the test circuits of Figure 9.8-2 and Figure 9.8-3 and establish
connection between ports under test.
3
(2)
Set switch S1 to position "B."
4
5
(3)
Set the generator to 800 Hz and adjust the output level to (-11) dBV as measured by
the voltmeter (see comment (4)).
6
(4)
Set switch S1 to position "A" and measure and record the input level of the EUT.
7
8
(5)
Calculate the gain at 800 Hz as the difference between the level set in step (3) and
the level measured in step (4).
9
(6)
Repeat step (2) through step (5) for frequencies of 1000, 2000, 2300, and 2600 Hz.
10
(7)
Repeat step (2) through step (6) for each of the following conditions as applicable:
11
(8)
Minimum current through EUT input and maximum current through EUT output
12
(9)
Maximum current through EUT input and maximum current through EUT output
13
(10) Maximum current through EUT input and minimum current through EUT output
14
15
16
17
18
19
20
(11) If significant ripple is noticed, i.e., the change in gain over the frequency range is not
smooth and monotonic, then with switch S1 in position "B," sweep the frequency
range from 800 Hz to 2450 Hz noting the frequency at which the minimum value is
indicated on the voltmeter. Sweep the frequency range from 2450 Hz to 2750 Hz
noting the frequency at which the maximum value is indicated on the voltmeter.
Repeat step (2) through step (7) for these two frequencies with the minimum and
maximum amplitude values.
21
(12) Repeat step (2) through step (8) for the opposite direction, if applicable.
22
23
24
25
9.8.6 Alternative Methods
26
27
28
9.8.7 Suggested Test Data
29
(2) Frequency or frequency band.
A method employing a white noise source and two bandpass filters may be used.
(1) Input level.
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(3) Output level.
2
(4) Through transmission paths.
3
(5) Comparison data.
4
(6) Loop simulator currents.
5
6
7
8
9.8.8 Comments
(1) Measure each combination of port types. Check all other operating modes, such as
conferencing, which might cause variations.
9
10
(2) Where a device has several identical ports, only one representative sample of each
through-transmission combination needs to be measured.
11
12
(3) A loop simulator circuit may be used when needed on the input and output ports in
place of the 600 ohm termination.
13
14
15
(4) The EUT input test level that should be used in testing protective circuits for
compliance is found in step (5) of subclause 9.1 for voice EUT, and in step (5) of
subclause 9.5 for data EUT.
16
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2
True
RMS
Voltmeter
3
A
4
B
S1
5
B
A
6
7
Loop Simulator
(Notes 1 & 2)
8
9
10
11
12
13
14
15
16
17
Loop Simulator
EUT
(Notes 1 & 2 & 4)
Frequency
Generator
(Note 3)
Note 1.
Select the appropriate loop simulator, holding circuit, or termination for the interface of the
EUT.
18
19
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
20
21
22
Note 3.
The output impedance of the signal source should be such that, in combination with or in
place of R1 of the two-wire loop simulator circuit, the source impedance is either 600
ohms or matches the circuit of ANSI/TIA-968-A Figures 1.8
23
24
Note 4.
The resistor R1 of the loop simulator may be replaced with the circuit of ANSI/TIA-968-A
Figures 1.8.
25
26
27
Figure 9.8-1. Through Transmission - SF Guard Bands, Analog
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
True
RMS
Voltmeter
A
B
S1
A
Loop Simulator
(Notes 1 & 2)
B
Loop Simulator
Figure 9.8-3
(Notes 1 & 2 & 4)
Frequency
Generator
(Note 3)
Note 1.
Select the appropriate loop simulator, holding circuit, or termination for the interface of the
EUT.
22
23
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
24
25
26
Note 3.
The output impedance of the signal source should be such that, in combination with or in
place of R1 of the two-wire loop simulator circuit, the source impedance is either 600
ohms or matches the circuit of ANSI/TIA-968-A Figures 1.8
27
28
Note 4.
The resistor R1 of the loop simulator may be replaced with the circuit of ANSI/TIA-968-A
Figures 1.8.
29
30
31
32
Figure 9.8-2. Through Transmission - SF Guard Bands, Digital
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2
3
4
5
6
7
8
9
10
11
Figure 9.8-3. Digital EUT Arrangement for Figure 9.8-2
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2
3
9.9
Return Loss, Tie Trunk - Two Wire ANSI/TIA-968-A, 4.5.2.6.1
4
5
6
7
8
9
10
9.9.1 Background
11
12
13
14
15
9.9.2 Purpose
16
17
18
9.9.3 Equipment
(1)
Spectrum analyzer SEL#34.
19
(2)
Tracking generator SEL#39.
Poor impedance matching of the CPE connecting to a tie trunk facility could result in
circuit instability, characterized by singing or echoing, and can cause crosstalk
interference; therefore good impedance matching is essential. Return Loss is a
measure of the degree of impedance match, i.e., the greater the magnitude (expressed
in dB) the better the match.
To measure the return loss of the various Tie Trunk interface ports of the EUT as
referenced to the appropriate impedance requirement. The impedance requirement for
two-wire Tie trunks is 600 ohms in series with 2.16 microfarads (µF).
20
21
Note: Refer to subclause 5.5 for equipment details.
22
23
24
9.9.4 Equipment States Subject To Test
25
26
27
9.9.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.9-1.
28
29
30
31
(2)
Set the tracking generator to 0.5 V rms (-6 dBV) or higher, and manually or
automatically sweep the band from 200 Hz to 3200 Hz as a minimum, with the
spectrum analyzer measuring the level, in dBV, across points A and B (switch S1 in
position "A"). This is the reference level measurement.
32
33
(3)
Without adjusting the tracking generator level, manually or automatically sweep the
same frequency band as used in step (2) with the spectrum analyzer now measuring
Idle state.
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the level, in dBV, across points B and C (switch in position "B").
2
3
4
(4)
The difference, in dB, between the reference level measured in step (2) and the level
measured in step (3), is the return loss of the EUT port at any given frequency. The
return loss will be a positive value.
5
6
7
9.9.6 Alternative Methods
8
9
10
9.9.7 Suggested Test Data
(1)
Return loss of the EUT at 200, 500, 1000, 2000, and 3200 Hz.
11
(2)
Minimum return loss measured in the 200 Hz to 3200 Hz band.
12
13
14
15
16
9.9.8 Comments
A commercial return loss bridge may be used instead of the bridge of Figure 9.9-1.
A variable frequency oscillator and a broadband or frequency selective voltmeter may
be used instead of the tracking generator and spectrum analyzer.
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2
3
4
5
6
7
Figure 9.9-1. Return Loss, Two-Wire
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9.10
Return Loss, Tie Trunk - Four Wire ANSI/TIA-968-A, 4.5.2.6.2
2
3
4
5
6
7
9.10.1 Background
Good return loss and transducer loss of the EUT connecting to a tie trunk facility
(usually a four-wire low loss connection) will prevent circuit instability characterized by
singing and echoes. Singing can result in crosstalk interference. Subclause 9.10 deals
with four-wire return loss and subclause 9.11 deals with transducer loss.
8
9
10
11
12
9.10.2 Purpose
13
14
15
9.10.3 Equipment
(1)
Spectrum analyzer SEL#34.
16
(2)
Tracking generator SEL#39
To measure the return loss of the various Tie Trunk input and output interface ports of
the EUT as referenced to the appropriate impedance requirement. The impedance
requirement for four-wire ports of the EUT is 600 ohms.
17
18
Note: Refer to subclause 5.5 for equipment details.
19
20
21
9.10.4 Equipment States Subject to Test
22
23
24
9.10.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.10-1.
25
26
27
28
(2)
Set the tracking generator to 0.5 V rms (-6 dBV) or higher, and manually or
automatically sweep the band from 200 Hz to 3200 Hz as a minimum, with the
spectrum analyzer measuring the level, in dBV, across points A and B (switch in
position "A"). This is the reference level measurement.
29
30
31
(3)
Without adjusting the tracking generator level, manually or automatically sweep the
same frequency band as used in step (2) with the spectrum analyzer now measuring
the level, in dBV, across points B and C (switch in position "B").
32
(4)
The difference, in dB, between the reference level measured in step (2) and the level
Idle state.
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2
measured in step (3), is the return loss of the EUT port at any given frequency. The
return loss will be a positive value.
3
(5)
Connect the EUT to the test circuit as shown in Figure 9.10-2.
4
(6)
Repeat step (2) through step (4).
5
6
7
9.10.6 Alternative Methods
8
9
10
11
9.10.7 Suggested Test Data
(1)
Return loss of the tip and ring leads of the EUT at 200, 500, 1000, 2000, and 3200
Hz.
12
13
(2)
Minimum return loss of the tip and ring leads of the EUT measured in the 200 Hz to
3200 Hz band.
14
15
(3)
Return loss of the tip 1 and ring 1 leads of the EUT at 200, 500, 1000, 2000, and
3200 Hz.
16
17
(4)
Minimum return loss of the tip 1 and ring 1 leads of the EUT measured in the 200 Hz
to 3200 Hz band.
18
19
20
21
22
23
9.10.8 Comments
A commercial return loss bridge may be used instead of the bridge of Figure 9.10-1.
When measuring return loss, a variable frequency oscillator and a broadband or
frequency selective voltmeter may be used instead of the tracking generator and
spectrum analyzer.
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2
3
4
5
6
Figure 9.10-1. Return Loss, Four-Wire, T&R
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2
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7
Figure 9.10-2. Return Loss, Four-Wire, T1&R1
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9.11
Transducer Loss, Tie Trunk - Four Wire ANSI/TIA-968-A, 4.5.2.6.3
2
3
4
9.11.1 Background
5
6
7
8
9
9.11.2 Purpose
Refer to subclause 9.10.1.
To measure the transducer loss from the receive port to the transmit port of a four-wire
Tie Trunk interface (forward direction) and from the transmit port to the receive port
(reverse direction).
10
11
12
9.11.3 Equipment
(1)
Spectrum analyzer SEL#34
13
(2)
Tracking generator SEL#39.
14
15
16
17
18
19
Note: Refer to subclause 5.5 for equipment details.
9.11.4 Equipment States Subject to Test
Idle state.
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2
3
4
5
9.11.5 Procedure
(1)
Adjust the tracking generator output level to -10.0 dBV into a 600-ohm load,
measured at 1004 Hz. Sweep the band from 200 Hz to 3200 Hz with the spectrum
analyzer measuring the level in dBV. This is the reference level measurement.
6
(2)
Connect the EUT to the test circuit of Figure 9.11-1.
7
8
(3)
Without adjusting the tracking generator level, sweep the same frequency band as
used in step (1) with the spectrum analyzer measuring the level in dBV.
9
10
11
(4)
The difference, in dB, between the reference level measured in step (1) and the level
measured in step (3), is the forward transducer loss of the EUT port at any given
frequency.
12
(5)
Connect the EUT to the test circuit of Figure 9.11-2.
13
(6)
Repeat step (3) and step (4) to measure the reverse transducer loss.
14
15
16
9.11.6 Alternative Methods
17
18
19
9.11.7 Suggested Test Data
20
21
22
23
24
25
26
9.11.8 Comments
None suggested.
Forward and reverse transducer losses at 200, 500, 1000, 2000, and 3200 Hz.
Transducer loss is expressed as a ratio of current in the receive pair as compared to the
transmit pair. This specific test procedure uses a more practical method by determining
the ratio of voltages instead of currents. This method is acceptable as long as the
correct impedances are maintained.
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2
3
4
5
6
Note: The source impedance of the tracking generator is 600 ohms.
Figure 9.11-1. Transducer Loss, Forward
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7
8
Note: The source impedance of the tracking generator is 600 ohms.
Figure 9.11-2 Transducer Loss, Reverse
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9.12 DC Conditions, OPS ANSI/TIA-968-A, 4.5.2.7
2
3
4
5
6
7
9.12.1 Background
Off-premise station (OPS) ports of premises communication systems (e.g., private
branch exchanges or key telephone systems) provide DC loop supervision network
control signaling and talking battery to the remote OPS stations (refer also to subclause
8.3).
8
9
10
11
12
9.12.2 Purpose
13
14
15
9.12.3 Equipment
(1)
Applicable loop simulator SEL#4
16
(2)
DC current meter SEL#19.
17
(3)
DC voltmeter SEL#22.
To verify that the voltage and current capabilities of the OPS port of the EUT are
compatible with the network requirements and that it provides sufficient direct current for
proper operation of network facilities and the remote OPS equipment.
18
Note: Refer to subclause 5.5 for equipment details.
19
20
21
9.12.4 Equipment States Subject To Test
22
23
24
25
9.12.5 Procedure
Active state.
Note: The requirements of ANSI/TIA-968-A, 4.5.2.7.1 and 4.5.2.7.2.1 are addressed in ANSI/TIA968-A, 4.4.1.4.1 and the test procedures are covered in subclause 8.3
26
27
(1)
Connect the EUT to test circuit of Figure 9.12-1.
28
(2)
Place the EUT into the talking state.
29
30
(3)
For Class B and Class C OPS interfaces, close switch S1, and measure the short
circuit current between T(OPS) and R(OPS).
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(4)
Open switch S1.
2
(5)
Place the OPS simulator into condition "1."
3
4
(6)
Adjust R2 as given in the table of ANSI/TIA-968-A, 4.5.2.7.2.3 for Class B and Class
C OPS interfaces.
5
(7)
Record the current flowing in the circuit.
6
(8)
Place the simulator circuit into condition "2" and repeat step (5) through step (7).
7
8
9
9.12.6 Alternative Methods
10
11
12
9.12.7 Suggested Test Data
(1)
Short circuit current (mA) for Class B and C OPS interfaces.
13
(2)
Minimum current under conditions "1" and "2" for Class B and C OPS interfaces.
14
15
16
17
9.12.8 Comments
(1)
The minimum and maximum current requirements do not apply to Class A OPS
interfaces. See subclause 8.3 for Class A OPS limitations.
18
19
(2)
The DC current into the OPS loop simulator circuit should be at least 20 mA for
conditions 1 and 2 specified in the table of ANSI/TIA-968-A, 4.5.2.7.2.3.
None suggested.
20
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4
5
6
7
8
Note: Loop current is measured with a current meter in series with the OPS loop simulator. Refer to
the ANSI/TIA-968-A Figure 1.7.
Figure 9.12-1. OPS DC Conditions
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9.13 Signal Power 3995 Hz - 4005 Hz – Not Network Control Signals ANSI/TIA-968A, 4.5.3.1
3
4
5
6
7
8
9
10
11
12
13
9.13.1 Background
14
15
16
17
18
9.13.2 Purpose
19
20
21
9.13.3 Equipment
(1)
Applicable loop simulator SEL#4.
22
(2)
Bandpass filter SEL#8
23
(3)
True rms AC voltmeter SEL#40.
It is necessary that the signal power in the 3995 Hz to 4005 Hz band be limited so that
the transmitted signal does not interfere with the modulating carrier frequencies of
multichannel carrier systems. Limits are be specified on both internal signal sources
and through gain of terminal equipment in the 3995 Hz to 4005 Hz frequency band.
An absolute level restriction is necessary for internal sources; an insertion loss
restriction is necessary for through gain equipment. The insertion loss restriction is
such that the equipment will not increase the signal level near 4 kHz relative to the level
of the normal voiceband frequencies.
To verify for the EUT that the voiceband signal power from internal sources, other than
live-voice, is limited in the 3995 Hz to 4005 Hz frequency band.
24
25
Note: Refer to subclause 5.5 for equipment details.
26
27
28
29
9.13.4 Equipment States Subject To Test
(1)
Off-hook, idle state.
30
31
(2)
Any off-hook state which transmits signals to the PSTN which are not intended for
network control.
32
33
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9.13.5 Procedure
(1)
Connect the EUT to the circuit of Figure 9.13-1.
5
(2)
Set the voltmeter to measure the signal level in dBm.
6
7
(3)
Place the EUT in the off-hook state and cause it to transmit an internal signal at
maximum power.
8
9
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
10
(5)
Repeat step (3) through step (4) for all other operating states.
11
12
13
14
15
9.13.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 9.13-1 and replace the bandpass filter
and true rms AC voltmeter with a signal analyzer (SEL#56).
16
(2)
Set the signal analyzer to measure the following:
17
(a)
Signal level in dBm, 600 ohms.
18
(b)
Averaging over 3 second.
19
(c)
Band pass power in the frequency range of 3995 Hz to 4005 Hz band.
20
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
21
22
23
(3)
Place the EUT in the desired off-hook state and cause it to transmit an internal signal
at maximum power.
24
25
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
26
(5)
Repeat step (2) through step (4) for other operating states, if applicable.
27
28
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4
9.13.7 Suggested Test Data
(1)
Operating states.
5
(2)
Signal power levels in dBm for the 3995 Hz to 4005 Hz band.
6
7
8
9.13.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
9
10
11
12
(2)
For EUT using recorded voice or synthesized voice, a message using both male
and female voices speaking a typical sentence that is repeated for a total length of
about 30 seconds, or long enough to obtain a 3-second average power in the 3995
Hz to 4005 Hz band is suggested.
13
14
(3)
A voltmeter with an averaging time of less than 3 seconds may be used, provided
that the measured value is adjusted based on the duty cycle of the signals.
15
16
17
(4)
The roll-off used in bandpass filters of the CODECs in digital EUTs causes the
signal power in the 3995 Hz to 4005 Hz band to be at least 30 dB down from the
reference value at 1000 Hz. Hence this requirement does not apply to digital EUT.
18
19
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2
3
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
4
5
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of clause
1 of ANSI/TIA-968-A.
6
7
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
8
9
10
Figure 9.13-1. Signal Power, 3995-4005 Hz, Internal Sources
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9.14 Through Transmission – 3995-4005 Hz vs 600-4000 Hz ANSI/TIA-968-A,
4.5.3.2
4
5
6
7
8
9.14.1 Background
The basis for this requirement is identical to that described in subclause 9.13
9
10
11
12
13
9.14.2 Purpose
14
15
16
9.14.3 Equipment
(1)
Applicable loop simulator SEL#4.
17
(2)
Bandpass filter SEL#8
18
(3)
Bandpass filter SEL#14.
19
(4)
Frequency generator SEL#27
20
(5)
True rms AC voltmeter SEL#40.
21
(6)
White noise generator SEL#45.
To verify for the EUT that through transmission of signals, is limited in the 3995 Hz to
4005 Hz frequency band vs the 600 Hz to 4000 Hz frequency band.
22
23
Note: Refer to subclause 5.5 for equipment details.
24
25
26
27
9.14.4 Equipment States Subject To Test
(1)
All equipment with through-transmission paths to the PSTN are subject to test.
28
29
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5
6
9.14.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.14-1 and establish connection
between the ports under test for minimum current condition of each port as
applicable.
7
(2)
Set switch S1 to position "A" and switch S2 to position "A."
8
(3)
Set the filter to pass the band of frequencies from 600 Hz to 3995 Hz.
9
(4)
Adjust the level of the white noise generator so that the voltmeter indicates -11 dBV.
10
11
(5)
Set switch S1 to position "B" and measure the signal present at the output side of the
EUT.
12
13
(6)
Calculate the gain of the through-transmission path in the band from 600 Hz to 3995
Hz from the levels obtained in step (4) and step (5).
14
(7)
Set switch S1 to position "A" and switch S2 to position "B."
15
16
(8)
Set the frequency generator to 4000 Hz and adjust the level to match the level in
step (4).
17
(9)
Set switch S1 to position "B" and measure the signal level.
18
(10)
Calculate the gain at 4000 Hz from the level obtained in step (8) and (9).
19
(11)
Repeat step (2) through step (10) for each of the following conditions as applicable:
20
21
(a)
Minimum current through EUT input and maximum current through EUT
output.
22
23
(b)
Maximum current through EUT input and maximum current through EUT
output.
24
25
(c)
Maximum current through EUT input and minimum current through EUT
output.
26
27
28
29
9.14.6 Alternative Methods
A discrete or swept frequency method may also be used.
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4
9.14.7 Suggested Test Data
(1)
Types of through-transmission paths.
5
(2)
Calculated net gain in the 600 Hz to 3995 Hz band.
6
(3)
Calculated net gain at 4000 Hz.
7
(4)
Loop simulator currents.
8
9
10
11
9.14.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
12
13
(2)
A voltmeter with an averaging time of less than 3 seconds may be used, provided
that the measured value is adjusted based on the duty cycle of the signals.
14
15
16
(3)
The roll-off used in bandpass filters of the CODECs in digital EUTs causes the
signal power in the 3995 Hz to 4005 Hz band to be at least 30 dB down from the
reference value at 1000 Hz. Hence this requirement does not apply to digital EUT.
17
18
19
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Note 1.
Select the appropriate loop simulator, holding circuit, or termination for the interface of the
EUT.
Note 1.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
Note 1.
The source impedance of the signal generator should be such that, in combination with or
in place of R1 of the loop simulator circuit, the source impedance is either 600 ohms or
matches the impedance of the circuit of Figure 1.8 in ANSI/TIA-968-A.
Note 1.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
Figure 9.14-1 Signal Power, 3995-4005 Hz vs 600-4000 Hz, Through Transmission
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4
5
6
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8
9
9.15 Non-LADC Longitudinal Voltage – 0.1 - 4 kHz ANSI/TIA-968-A, 4.5.4
9.15.1 Background
This requirement ensures that spurious or unintended signals transmitted from terminal
equipment at frequencies in the voiceband do not interfere with telephone company
transmission systems operating in that frequency range as a result of crosstalk.
10
11
12
13
14
9.15.2 Purpose
15
16
17
9.15.3 Equipment
(1)
Applicable loop simulator SEL#4
18
(2)
Bandpass filter SEL#12.
19
(3)
True rms AC voltmeter SEL#40.
20
(4)
Spectrum analyzer SEL#34
21
(5)
Frequency Generator SEL#27
To verify that the EUT does not apply excessive longitudinal power to the PSTN in the
voiceband.
22
Note: Refer to subclause 4.3 for equipment details.
23
24
25
26
9.15.4 Equipment States Subject to Test
(1)
On-hook.
27
(2)
All active operating states.
28
29
30
31
32
Note: Terminal equipment may require special attention to ensure it is properly configured for this
test. For example, if the equipment would normally be connected to ac-power ground, coldwater-pipe ground, or if it has a metallic or partially metallic exposed surface, then these points
should be connected to the test ground plane. Similarly, if the EUT provides connections to
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4
5
other equipment through which ground may be introduced to the equipment, then these points
should be connected to the test ground plane. Equipment which does not contain any of these
potential connections to ground should be placed on a conductive plate which is connected to
the test ground plane (see comment 1); this applies to both non-powered and ac-powered
equipment.
6
7
8
9
9.15.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.15-1.
10
(2)
Place the EUT in the on-hook state.
11
12
13
(3)
Set the bandpass filter to measure in the 100 Hz to 4000 Hz band and record the
voltmeter reading. The weighting network has a transfer function of F/4000, where F
is the frequency in Hz.
14
15
16
17
18
19
20
Note: Correct the measured result for the voltage divider relationship of the termination. Adjustment
is +3.1 dB.
(4)
Place the EUT in one of the off-hook states. Conduct these tests in accordance with
the conditions of ANSI/TIA-968-A subclause 4.5.7.1 to 4.5.7.3, as appropriate (see
comment 3 and 4).
(5)
Repeat step (3) for all possible off-hook states.
21
22
Note: step (3) through step (5) should be measured at minimum and maximum loop currents
attainable with the loop simulator for all off-hook states, if applicable.
23
24
25
26
27
9.15.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 9.15-1 and replace the bandpass filter
and true rms AC voltmeter with a spectrum analyzer.
28
(2)
Place the EUT in the on-hook state.
29
30
(3)
Set the spectrum analyzer to measure in the 100 Hz to 4000 Hz band and record the
result. See comment (2).
31
32
Note: Correct the measured result for the voltage divider relationship of the termination. Adjustment
is +3.1 dB.
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2
3
4
5
(4)
Place the EUT in one of the off-hook states. Conduct these tests in accordance with
the conditions of ANSI/TIA-968-A subclause 4.5.7.1 to 4.5.7.3, as appropriate (see
comment 3 and 4).
(5)
Repeat step (3) for all possible off-hook states.
6
7
Note: step (3) through step (5) should be measured at minimum and maximum loop currents
attainable with the loop simulator for all off-hook states, if applicable.
8
9
10
9.15.7 Suggested Test Data
(1)
Band measured.
11
(2)
Voltage level in dBV.
12
(3)
Equipment states.
13
14
15
16
17
18
9.15.8 Comments
(1)
An EUT that is not normally grounded should be set in its normal position directly
on a conductive plate. The overall area of the conductive plate should be at least
50% greater than that of the base of the EUT. This represents the closest proximity
to ground that is likely to be encountered by the EUT.
19
20
(2)
When using a spectrum analyzer the total rms voltage over the 100 Hz to 4 kHz
band can be calculated using the expression:
21
22
23
24
25
26
27
28
29
30
31
32
33
Vt = (V12 + V22 + . . . + Vn2 )0.5
where Vt is the total rms voltage over the 100 Hz to 4 kHz band and V1, V2,
V3....Vn are the spectral components within that band that are within 20 dB of the
limit for that band.
(3)
For approved terminal equipment or protective circuits with provision for throughtransmission from other equipment, apply a 1000 Hz signal from a 600 ohm source
that results in a power output of (-13) dBm delivered into a 600 ohm load at the
network interface.
(4)
For approved data protective circuits or approved terminal equipment or protective
circuits with non-approved signal source input, such as music on hold, apply a 1000
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2
3
Hz signal that is 10 dB higher then the overload level point.
(5)
See ANSI/TIA-968-A subclause 4.5.7.1 through 4.5.7.3 for the conditions that apply
for different equipment types.
4
5
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2
3
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
4
5
Note 2.
Connect the resistive network in place of R1 of the loop simulator. Refer to the figure 4.5
of ANSI/TIA-968-A. Use 300 ohm resistors that are adequately matched.
6
7
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
8
9
10
11
Figure 9.15-1. Voiceband Longitudinal Voltage
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2
9.16 Non-LADC Metallic Voltage - 4 kHz to 30 MHz ANSI/TIA-968-A, 4.5.5.1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
9.16.1 Background
32
33
34
35
9.16.2 Purpose
36
37
38
9.16.3 Equipment
This requirement ensures that spurious or unintended signals transmitted from terminal
equipment at frequencies above voiceband do not interfere with telephone company
transmission systems or services that function at such frequencies. The most limiting
situations are those that involve subscriber multichannel analog carrier systems. These
are systems that are used in the local exchange plant to obtain a wire pair gain
advantage. In these systems, the signals to and from several subscribers are
multiplexed onto a wire pair using frequency division. Each direction of transmission for
each subscriber uses either 4 kHz (single sideband) or 8 kHz (double sideband) of
frequency spectrum. Generally, the carrier systems most susceptible to crosstalk are
those that use double sideband modulation methods, 8 kHz of spectrum for each
direction of transmission per channel.
Accordingly, the requirements in ANSI/TIA-968-A are specified in 8 kHz bands relative
to the center frequency of each band. Thus the limits in each band are based on the
susceptibility of the affected analog multichannel carrier system, crosstalk
characteristics of the wire pair cable facilities, and the characteristic terminating
impedance of the cable facilities. The limit is therefore established for each 8 kHz band
centered in the frequency specified in the tables up to 270 kHz.
The 100-millisecond averaging time for frequencies less than 270 kHz approximates the
minimum time necessary for the interfering signal to affect the transmission
performance of subscriber analog carrier systems on other cable pairs. For frequencies
greater than 270 kHz, a 2-microsecond averaging time is specified. This averaging time
is approximately the reciprocal of the Nyquist rate of "T" carrier. It represents the time
interval appropriate to interference with the "T" carrier transmission. Such a signal
duration will result in pulse interference and consequently transmission errors. One
broadband requirement above 270 kHz is adequate.
To verify that the EUT does not apply excessive out-of-band power to the PSTN.
(1)
Applicable loop simulator SEL#4.
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(2)
Bandpass filter SEL#9
2
(3)
Digital sampling storage oscilloscope SEL#24.
3
(4)
Spectrum analyzer SEL#34
4
(5)
Frequency Generator SEL#27
5
6
7
8
9
Note: Refer to subclause 4.3 for equipment details.
9.16.4 Equipment States Subject to Test
(1)
On-hook.
10
(2)
All active operating states.
11
12
13
9.16.5 Procedure
Note: See comments (1), (2), (3) and (6) before performing tests.
14
15
(1)
Connect the EUT to the test circuit of Figure 9.16-1.
16
(2)
Place the EUT in the on-hook state.
17
(3)
Select R1 to be 300 ohms.
18
19
(4)
Measure the energy in each 8 kHz band whose center frequency is in the range of 8
kHz to 12 kHz, and record the results.
20
(5)
Select R1 to be 135 ohms.
21
22
(6)
Measure the energy in each 8 kHz band whose center frequency is in the range of 12
kHz to 90 kHz, and record the results.
23
24
(7)
Measure the energy in each 8 kHz band whose center frequency is in the range of 90
kHz to 266 kHz and record the worst case result.
25
26
27
(8)
Place the EUT in each of its off-hook states as specified in ANSI/TIA-968-A
subclause 4.5.7.2, and condition the EUT as specified in ANSI/TIA-968-A subclause
4.5.7.3 or 4.5.7.4, as appropriate (see comment 7 and 8).
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2
(9)
Repeat step (3) through step (7) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
3
4
5
(10) Connect the EUT to the test circuit of Figure 9.16-2, and set the passband of the filter
to measure broadband energy in the frequency range 270 kHz to 30 MHz (see
comment 4 and 5).
6
(11) Condition the EUT to the on-hook state.
7
(12) Set the digital oscilloscope to provide:
8
(a)
2 µs per sample;
9
(b)
Trigger at (-25) dBV;
10
(c)
Accumulate mode;
11
(d)
Vertical scale 0 mV to 250 mV full height.
12
13
Note: If the baseline contains 1000 points then a single trace will take 2 ms.
14
15
(13) Program the oscilloscope to accumulate 10 traces.
16
17
(14) Record the value of the largest peak measured and convert to Vrms by multiplying by
0.707.
18
19
20
(15) With the EUT in each of its active operating states as specified in ANSI/TIA-968-A
subclause 4.5.7.2, condition the EUT as specified in ANSI/TIA-968-A subclause
4.5.7.3 or 4.5.7.4, as appropriate (see comment 7 and 8).
21
22
(16) Repeat step (13) and step (14) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
23
24
9.16.6 Alternative Method - Broadband Procedure
25
Note: See comments (2), (3), and (5).
26
27
(1)
Connect the EUT to the test circuit of Figure 9.16-1.
28
(2)
Place the EUT in the on-hook state.
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(3)
Select R1 to be 300 ohms.
2
3
(4)
Set the spectrum analyzer to measure broadband energy in the frequency range 4
kHz to 16 kHz, using the required termination, and record the result.
4
(5)
Select R1 to be 135 ohms.
5
6
(6)
Set the spectrum analyzer to measure broadband energy in the frequency range 8
kHz to 94 kHz, and record the result.
7
8
(7)
Set the spectrum analyzer to measure broadband energy in the frequency range 86
kHz to 270 kHz, and record the worst case result.
9
10
(8)
Set the spectrum analyzer to measure broadband energy in the frequency range 270
kHz to 6 MHz, and record the worst case result.
11
12
(9)
Set the spectrum analyzer to measure broadband energy in the frequency range 6
MHz to 30 MHz, and record the worst case result.
13
14
15
(10) Place the EUT in each of its off-hook states as specified in ANSI/TIA-968-A
subclause 4.5.7.2, and condition the EUT as specified in ANSI/TIA-968-A subclause
4.5.7.3 or 4.5.7.4, as appropriate (see comment 7 and 8).
16
17
(11) Repeat step (3) through step (9) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
18
19
20
(12) If the test results obtained in step (4) and step (6) through step (9) do not exceed the
maximum limits specified in ANSI/TIA-968-A subclause 4.5.5.1, then no further tests
are required (see comment 2).
21
22
23
9.16.7 Suggested Test Data
(1)
Center frequencies.
24
(2)
Start and stop frequencies.
25
(3)
Measured or calculated signal power values.
26
(4)
Equipment state.
27
28
29
9.16.8 Comments
When using a detector that measures individual frequency components, the following
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2
3
4
5
6
7
8
9
10
procedure should be employed.
(1)
Total the voltages which are within 6 dB of the specified limit in each consecutive
band. If the sum of these voltages exceeds the limits, recheck the measurement at a
frequency centered over the band with the apparent failure.
The total rms voltage can be calculated using the expression:
Vt = (V12 + V22 + . . . + Vn2 )0.5
Note: This expression assumes that the spectral components have random phase relationships.
11
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2
3
4
5
6
7
(2)
The broadband measurement procedure may be used for the purpose of economy of
measurement. If the value obtained is lower than the most restrictive limit specified
for that frequency range, then the signal levels in 8 kHz bands in that range will be
lower than that specified for the most restrictive 8 kHz band. However, the main
procedure of subclause 9.16.5 should be used when the requirements are not met as
the signal levels in each band may still be within specified limits. Refer to ANSI/TIA968-A subclause 4.5.5.1.
8
9
10
(3)
If a spectrum analyzer is used and it does not have an 8 kHz bandwidth, a 10 kHz
bandwidth may be used. Application of a correction factor, additional measurements,
or both, may be required to compensate for the wider bandwidth.
11
12
13
(4)
If a failure condition is noted when a 10 kHz bandwidth is used and the spectral
content has uneven distribution, it may be necessary to check that reading, using a
higher resolution.
14
(5)
The total rms voltage over an 8 kHz band can be calculated using the expression:
15
16
17
18
19
20
21
Vt = (V12 + V22 + . . . + Vn2 )0.5
where Vt is the total rms voltage over any 8 kHz band and V1, V2, V3....Vn are the
spectral components within that band that are within 20 dB of the limit for the band
in question.
22
23
24
25
26
27
28
29
30
31
32
Note: This expression assumes that the spectral components have random phase relationships.
If the spectral content of a band is evenly distributed, then the equivalent rms
power in an 8 kHz band can be found by subtracting 1 dB from the measured
power using a 10 kHz bandwidth.
Since this is a measurement of a metallic (balanced) circuit, the only ground
connection should be that of the line cord of the oscilloscope or spectrum analyzer.
(6)
See ANSI/TIA-968-A subclause 4.5.7.2 through 4.5.7.4 for the conditions that apply
for different equipment types.
33
34
35
36
(7)
For approved terminal equipment or protective circuits with provision for throughtransmission from other equipment, apply a 1000 Hz signal from a 600 ohm source
that results in a power output of (-13) dBm delivered into a 600 ohm load at the
network interface.
37
(8)
The EUT input test levels and frequencies that should be used in testing protective
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circuits for compliance with all out-of-band frequencies are as follows:
2
3
4
(a)
For approved data protective circuits, apply a 1000 Hz signal that is 10 dB
higher then the overload point as determined in subclause 9.34.5.
(b)
For approved terminal equipment or approved protective circuits with nonapproved signal source input, such as music on hold, apply a swept sinusoidal
signal with a frequency range of 200 Hz to 20 kHz and the level set at the
overload point determined in subclause 9.34.5.
5
6
7
8
9
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2
3
4
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
5
6
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
7
8
9
10
Note 3.
The resistor shown (R1) is connected in place of R1 as shown in the loop simulator
drawing. The resistor has a value of 300 ohms for frequencies of 4 kHz to 12 kHz and
135 ohms for frequencies of 12 kHz to 30 MHz. Capacitor C1 of the loop simulator
should be capable of coupling the frequencies covered by this test.
11
12
Note 4.
The spectrum analyzer should provide a balanced input, or an isolation transformer or
balun transformer may be used.
13
14
Figure 9.16-1. Non-LADC Metallic 4 kHz to 30 MHz
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2
3
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
4
5
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
6
7
8
Note 3.
The resistor shown (R1) is connected in place of R1 as shown in the loop simulator
drawing. The resistor has a value of 135 ohms. Capacitor C1 of the loop simulator
should be capable of coupling the frequencies covered by this test.
9
10
Note 4.
The oscilloscope should provide a balanced input, or an isolation transformer or balun
transformer may be used.
11
12
13
Figure 9.16-2. Non-LADC Metallic 270 kHz to 30 MHz
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9.17 Non-LADC Longitudinal Voltage - 4 kHz to 6 MHz ANSI/TIA-968-A, 4.5.5.2
2
3
4
5
6
7
9.17.1 Background
The basis for these requirements is identical to that described in subclause 8.16.1
except that the wire pair crosstalk characteristics are such that there is greater crosstalk
coupling with longitudinal voltages. Thus, there are limits on both in-band and out-ofband longitudinal voltages.
8
9
10
11
9.17.2 Purpose
12
13
14
9.17.3 Equipment
(1)
Applicable loop simulator SEL#4
15
(2)
Bandpass filter SEL#9
16
(3)
Digital sampling storage oscilloscope SEL#24.
17
(4)
Spectrum Analyzer SEL#34
18
(5)
Frequency Generator SEL#27
To verify that the EUT does not apply any excessive out-of-band longitudinal signal
power to the PSTN.
19
20
Note: Refer to subclause 4.3 for equipment details.
21
22
23
24
9.17.4 Equipment States Subject to Test
(1)
On-hook.
25
(2)
All active operating states.
26
27
28
29
30
31
32
Note: Terminal equipment may require special attention to ensure it is properly configured for this
test. For example, if the equipment would normally be connected to ac-power ground, coldwater-pipe ground, or if it has a metallic or partially metallic exposed surface, then these points
should be connected to the test ground plane. Similarly, if the EUT provides connections to
other equipment through which ground may be introduced to the equipment, then these points
should be connected to the test ground plane. Equipment which does not contain any of these
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3
potential connections to ground should be placed on a conductive plate which is connected to
the test ground plane (see comment 6); this applies to both non-powered and ac-powered
equipment.
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2
3
4
9.17.5 Procedure
Note: See comments (1), (2), (3) and (5).
5
6
(1)
Connect the EUT to the test circuit of Figure 9.17-1.
7
(2)
Place the EUT in the on-hook state.
8
(3)
Select R1 = R2 = 150 ohms and R3 = 425 ohms.
9
10
(4)
Measure the energy in each 8 kHz band whose center frequency in the range of 8
kHz to 12 kHz and record the result.
11
12
13
14
Note: The measured result should be corrected for the voltage divider relationship of the termination.
Adjustment is (+1.4) dB.
(5)
Select R1 = R2 = 67.5 ohms and R3 = 56.3 ohms.
15
16
(6)
Measure the energy in each 8 kHz band whose center frequency is in the range 12
kHz to 42 kHz and record the result.
17
18
(7)
Measure the energy in each 8 kHz band whose center frequency is in the range 42
kHz to 266 kHz and record the worst case result.
19
20
21
22
23
24
Note: Correct the results measured in step (6) and step (7) for the voltage divider relationship of the
termination. Adjustment is (+4) dB.
(8)
Place the EUT in each of its off-hook states as specified in ANSI/TIA-968-A
subclause 4.5.7.2, and condition the EUT as specified in ANSI/TIA-968-A subclause
4.5.7.1, 4.5.7.3 or 4.5.7.4, as appropriate (see comment 9 and 10).
25
26
(9)
Repeat step (6) and step (7) at minimum and maximum loop currents attainable with
the loop simulator, if applicable.
27
28
29
(10) Connect the EUT to the test circuit of Figure 9.17-2 and set the passband of the filter
to measure broadband energy in the range 270 kHz to 6 MHz. (see comment 6 and
7).
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(11) Place the EUT in the on-hook state.
2
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(12) Set the digital oscilloscope to provide:
2
(a)
2 microseconds (µs) per sample;
3
(b)
Trigger at -40 dBV;
4
(c)
Accumulate mode;
5
(d)
Vertical scale 0 mV to 250 mV full height.
6
7
8
9
10
11
Note: If the baseline contains 1000 points then a single trace will take 2 ms.
(13) Program the oscilloscope to accumulate 10 traces.
(14) Record the value of the largest peak measured and convert to V rms by multiplying
by 0.707.
12
13
Note: Correct the results measured in step (14) for the voltage divider relationship of the termination.
Adjustment is (+4) dB.
14
15
16
17
(15) With the EUT in each of its active operating states as specified in ANSI/TIA-968-A
subclause 4.5.7.2, condition the EUT as specified in ANSI/TIA-968-A subclause
4.5.7.1, 4.5.7.3 or 4.5.7.4, as appropriate (see comment 9 and 10).
18
19
(16) Repeat step (13) and step (14) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
20
21
22
23
9.17.6 Alternative Methods - Broadband Procedure
(1)
Connect the EUT to the test circuit of Figure 9.17-1.
24
(2)
Place the EUT in the on-hook state.
25
(3)
Select the R1 = R2 = 150 ohms and R3 = 425 ohms.
26
27
(4)
Set the spectrum analyzer to measure broadband energy in the 4 kHz to 16 kHz
band and record the result.
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2
3
Note: Correct the results in step (4) by (+1.4) dB to accommodate the voltage divider.
(5)
Select R1 = R2 = 67.5 ohms and R3 = 56.3 ohms.
4
5
(6)
Set the spectrum analyzer to measure broadband energy in the 12 kHz to 46 kHz
band and record the result.
6
7
(7)
Set the spectrum analyzer to measure broadband energy in the 42 kHz to 270 kHz
band and record the worst-case result.
8
9
(8)
Set the spectrum analyzer to measure broadband energy in the 270 kHz to 6 MHz
band and record the worst-case result.
10
Note: Correct the results in step (6) and step (8) by (+4) dB to accommodate the voltage divider.
11
12
13
(9)
Place the EUT in each of its off-hook states as specified in ANSI/TIA-968-A
subclause 4.5.7.2, and condition the EUT as specified in ANSI/TIA-968-A subclause
4.5.7.1, 4.5.7.3 or 4.5.7.4, as appropriate (see comment 9 and 10).
14
15
(10) Repeat step (3) through step (8) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
16
17
18
9.17.7 Suggested Test Data
(1)
Center frequencies.
19
(2)
Start and stop frequencies.
20
(3)
Power levels, measured or calculated.
21
(4)
Equipment state.
22
23
24
25
9.17.8 Comments
(1)
When measuring with a detector that measures individual frequency components, the
following procedure should be used.
26
27
28
29
(2)
For all measured voltages within 6 dB of the specified limit in each consecutive band,
calculate the total rms voltage as shown below. If the sum of these voltages exceeds
the limit of the most restrictive value for these bands, then recheck the measurement
at sufficient frequencies centered over the bands involved in the failure.
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The total rms voltage can be calculated using the expression:
2
3
4
5
Vt = (V12 + V22 + . . . + Vn2 )0.5
Note: This expression assumes that the spectral components have random phase relationships.
6
7
8
9
10
11
12
(4)
The broadband measurement procedure may be employed for the purpose of
economy of measurement. If the value obtained is lower than the most restrictive
limit specified for that frequency range, then the signal levels in any 8 kHz band in
that range will be lower than the limit specified for the most restrictive 8 kHz band.
However, the main procedure of subclause 9.17.5 should be used when the
requirements are not met as the signal levels in each bandwidth may still be within
specified limits. Refer to ANSI/TIA-968-A subclause 4.5.5.2.
13
14
15
(5)
If a spectrum analyzer is used and it does not have an 8 kHz bandwidth, a 10 kHz
bandwidth may be used. Application of a correction factor, additional measurements,
or both, may be required to compensate for the wider bandwidth.
16
17
18
(6)
If a failure condition is noted when a 10 kHz bandwidth is used and the spectral
content has uneven distribution, it may be necessary to check that reading, using a
higher resolution.
19
20
(7)
The total rms voltage over an 8 kHz band can be calculated by the following
impression:
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Vt = (V12 + V22 + . . . + Vn2 )0.5
where Vt is the total rms voltage over an 8 kHz band and V1, V2, V3...Vn are the
spectral components within that band and are within 20 dB of the limit for the band
in question.
Note: This expression assumes that the spectral components have random phase relationships.
If the spectral content of a band is evenly distributed, the equivalent rms power in
an 8 kHz band can be found by subtracting 1 dB from the measured power using a
10 kHz bandwidth.
(8)
See ANSI/TIA-968-A subclause 4.5.7.1 through 4.5.7.4 for conditions that apply for
different equipment types.
(9)
For approved terminal equipment or protective circuits with provision for through169
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2
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transmission from other equipment, apply a 1000 Hz signal from a 600 ohm source
that results in a power output of -13 dBm delivered into a 600 ohm load at the
network interface.
4
5
(10) The EUT input test levels and frequencies that should be used in testing protective
circuits for compliance with all out-of-band frequencies are as follows:
6
7
(a)
For approved data protective circuits, apply a 1000 Hz signal that is 10 dB
higher then the overload point as determined in subclause 9.34.5.
8
9
10
11
(b)
For approved terminal equipment or protective circuits with non-approved signal
source input, such as music on hold, apply a swept sinusoidal signal with a
frequency range of 200 Hz to 20 kHz and the level set at the overload point
determined in subclause 9.34.5.
12
13
14
15
(11) EUT that is not normally grounded should be set in its normal position directly on a
conductive plate. It is recommended that the overall area of the conductive plate be
at least 50% greater than that of the base of the EUT. This represents the closest
proximity to ground that is likely to be encountered by the EUT.
16
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2
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
3
4
5
Note 2.
Connect the resistive network in place of R1 of the loop simulator. Capacitor C1 of the
loop simulator should be capable of coupling the frequencies covered by this test. The
resistors R1 and R2 should be adequately matched.
6
7
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
8
9
Figure 9.17-1. Non-LADC Longitudinal 4 kHz to 6 MHz
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2
3
4
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
5
6
7
Note 2.
Connect the resistive network in place of R1 of the loop simulator. Capacitor C1 of the
loop simulator should be capable of coupling the frequencies covered by this test. The
resistors R1 and R2 should be adequately matched.
8
9
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
11
12
13
Figure 9.17-2. Non-LADC Longitudinal 270 kHz to 6 MHz
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9.18
Metallic Voltage - 0.01 kHz to 30 MHz, LADC ANSI/TIA-968-A, 4.5.6.1, 4.5.6.2
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
9.18.1 Background
19
20
21
22
9.18.2 Purpose
23
24
9.18.3 Equipment
25
(1) Applicable loop simulator SEL#4.
26
(2) Bandpass filter SEL#9.
27
(3) Bandpass filter SEL#10.
28
(4) Bandpass filter SEL#11.
29
(5) Companion terminal equipment SEL#15.
30
(6) Digital sampling storage oscilloscope SEL#24.
31
(7) Spectrum Analyzer SEL#34.
32
(8) True rms AC voltmeter SEL#40.
The basic principle for establishing LADC signal power limits is similar to that for
non-LADC except that there is increased administration of the loop plant by the
telephone companies in selecting wire pairs for digital transmission and analog carrier
systems. Such administration results in the wire pairs selected not being in the same
binder group. Increased administration stems from the fact that there is need to
accommodate more digital transmission in the loop plant, which requires higher
frequencies and greater signal power.
The technical rules adopted here are based on the sensitivity of digital equipment to
other digital signals for frequencies below 270 kHz and on basic voiceband equipment
sensitivities to digital signals. The limits on the 8 kHz bands from 4 kHz to 270 kHz are
based on analog multichannel carrier sensitivity but at significantly less stringent levels
than required in non-LADC applications because of the special administrative
procedures followed for the digital system and analog carrier applications.
To verify that the EUT does not apply excessive metallic power to the network for
LADC equipment.
33
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Note: Refer to subclause 5.5 for equipment details.
2
3
4
5
6
9.18.4 Equipment States Subject to Test
7
8
9
9.18.5 Procedure
Active and transmitting data.
Note: Refer to 4.5.7.5 through 4.5.7.8 for applicable test conditions.
10
11
12
13
9.18.6 Frequencies Below 4 kHz ANSI/TIA-968-A, 4.5.6.1
14
(2) Select the 10 Hz to 4000 Hz bandpass filter.
15
16
(3) Cause the EUT to transmit an output signal in accordance with ANSI/TIA-968-A,
subclause 4.5.7.6 and 4.5.7.7.
17
(4) Record the voltmeter reading.
18
(5) Repeat step (3) and step (4) for all possible states.
19
(1) Connect the EUT to the test circuit of Figure 9.18-1.
Note: The remaining steps are only applicable to four-wire EUTs.
20
(1) Connect the EUT to the test circuit of Figure 9.18-2.
21
(2) Select the 10 Hz to 4000 Hz bandpass filter.
22
(3) Repeat step (3) through step (5).
23
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2
3
4
5
9.18.7
100 Hz Bands in the Frequency Range 0.7 kHz to 4kHz ANSI/TIA-968-A,
4.5.6.1.2; 100 Hz Bands in the Frequency Range 4 kHz to 270 kHz
ANSI/TIA-968-A, 4.5.6.2.1
6
(1) Connect the EUT to the test circuit of Figure 9.18-3.
7
8
(2) Cause the EUT to transmit an output signal in accordance with subclause 4.5.7.6 and
4.5.7.7 of ANSI/TIA-968-A.
9
(3) Measure the rms voltage averaged over 100 ms with a bandwidth of 100 Hz.
Note: See comments (1) and (2).
10
11
12
(4) Record the highest measured value and its associated frequency and any test results
that exceed (-6) dBV for center frequencies in each 100 Hz band between 750 Hz
and 3950 Hz.
13
14
15
(5) Record the highest measured value and its associated frequency and any test results
that exceed (-5) dBV for center frequencies in each 100 Hz band between 4.05 kHz
and 4.60 kHz.
16
17
18
(6) Compare the results with the allowed limit for each 100 Hz band having a center
frequency between 4.60 kHz and 5.45 kHz, and record the measured value having
the smallest margin relative to the allowed limit and its frequency.
19
20
21
(7) Compare the results with the allowed limit for each 100 Hz band having a center
frequency between 5.45 kHz and 59.12 kHz, and record the measured value having
the smallest margin relative to the allowed limit and its frequency.
22
23
24
(8) Compare the results with the allowed limit for each 100 Hz band having a center
frequency between 59.12 kHz and 266 kHz, and record the measured value having
the smallest margin relative to the allowed limit and its frequency.
25
(9) Repeat step (2) through step (8) for all operating conditions.
26
Note: The remaining steps are only applicable to four-wire EUTs.
27
(10) Connect the EUT to the test circuit of Figure 9.18-4.
28
(11) Repeat step (2) through step (9).
29
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2
3
4
9.18.8 8kHz bands Over the Frequency Range of 4 kHz to 270 kHz ANSI/TIA-968A, 4.5.6.2.2
5
6
(2) Cause the EUT to transmit an output signal in accordance with subclause 4.5.7.6 and
4.5.7.7 of ANSI/TIA-968-A.
7
(3) Measure the rms voltage averaged over 100 ms with a bandwidth of 8 kHz.
(1) Connect the EUT to the test circuit of Figure 9.18-3.
8
9
10
(4) Compare the results with the allowed limit for each 8 kHz band having a center
frequency between 8 kHz and 120 kHz, and record the measured value having the
smallest margin relative to the allowed limit and its frequency.
11
12
13
(5) Compare the results with the allowed limit for each 8 kHz band having a center
frequency between 120 kHz to 266 kHz, and record the measured value having the
smallest margin relative to the allowed limit and its frequency.
14
(6) Repeat step (2) through step (5) for all operating conditions.
15
Note: The remaining steps are only applicable to four-wire EUTs.
16
(7) Connect the EUT to the test circuit of Figure 9.18-4.
17
(8) Repeat step (2) through step (6).
18
9.18.9 RMS Voltages at Frequencies Above 270 kHz ANSI/TIA-968-A, 4.5.6.2.3
19
Note: See comments (1), (2) and (3).
20
(1) Connect the EUT to the test circuit of Figure 9.18-5.
21
(2) Select the 270-kHz to 30-MHz bandpass filter.
22
(3) Set the digital oscilloscope to provide:
23
(a)
2 µs per sample;
24
(b)
Trigger at (-25) dBV;
25
(c)
Accumulate mode;
26
(d)
Vertical scale 0 mV to 100 mV full height.
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Note: If the baseline contains 1000 points then a single trace will take 2 ms.
2
(4)
Program the oscilloscope to accumulate 10 traces.
3
4
(5)
Cause the EUT to transmit an output signal in accordance with subclause 4.5.7.6 and
4.5.7.7.
5
6
(6)
Record the value of the largest peak measured and convert to Vrms by multiplying by
0.707.
7
Note: The remaining steps are only applicable to four-wire EUTs.
8
(7)
Connect the EUT to the test circuit of Figure 9.18-6.
9
(8)
Repeat step (2) through step (6).
10
11
9.18.10 Peak Voltages at Frequencies Above 4 kHz ANSI/TIA-968-A, 4.5.6.2.4
Note: See comments (1) and (2).
12
(1) Connect the EUT to the test circuit Figure 9.18-5.
13
(2) Select the 4 kHz to 30-MHz bandpass filter.
14
(3) Set the digital oscilloscope to provide:
15
(a)
2 microseconds (µs) per sample;
16
(b)
Trigger at 0.4 V peak;
17
(c)
Accumulate mode;
18
(d)
Vertical scale 0 V to 5 V full height.
19
(4) Accumulate peak readings for a 10-second period.
20
21
(5) Cause the EUT to transmit an output signal in accordance with subclauses 4.5.7.6
and 4.5.7.7 of ANSI/TIA-968-A.
22
(6) Record the value of the largest peak measured.
23
24
Note: The remaining steps are only applicable to four-wire EUTs.
(7) Connect the EUT to the test circuit of Figure 9.18-6.
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(8) Repeat step (2) through step (6).
2
3
4
9.18.11 Alternative Methods
5
6
7
9.18.12 Suggested Test Data
8
(2) Voltage levels, measured or calculated.
9
(3) Equipment state.
10
11
12
9.18.13 Comments
13
(2) See ANSI/TIA-968-A, subclauses 4.5.7.5 through 4.5.7.8 further information.
None suggested.
(1) Center frequencies measured or frequency band measured.
(1) A quasi-random signal source may be used for testing.
14
15
16
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2
3
4
Figure 9.18-1. LADC Metallic 10 Hz to 4 kHz, T&R
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2
3
4
Figure 9.18-2. LADC Metallic 10 Hz to 4 kHz, T1 & R1
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2
3
4
5
6
7
Note: The spectrum analyzer should provide a balanced input, or an isolation transformer should be
used.
Figure 9.18-3. LADC Metallic 700 Hz to 270 kHz, T&R
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2
3
4
5
6
7
Note: The spectrum analyzer should provide a balanced input, or an isolation transformer should be
used.
Figure 9.18-4. LADC Metallic 700 Hz to 270 kHz, T1&R1
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2
3
4
Note 1.
The oscilloscope should provide a balanced input.
5
Note 2.
Refer to the procedure for selection of the appropriate bandpass filter.
6
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
7
8
9
10
Figure 9.18-5. LADC Metallic 270 kHz to 30 Mhz, T&R
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2
3
4
5
Note 1.
The oscilloscope should provide a balanced input.
6
Note 2.
Refer to the procedure for selection of the appropriate bandpass filter.
7
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
8
9
10
Figure 9.18-6. LADC Metallic 270 kHz to 30 MHz, T1&R1
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9.19 Longitudinal Voltage - 0.01 kHz to 6 MHz, LADC ANSI/TIA-968-A, 4.5.6.3
2
3
4
5
6
7
9.19.1 Background
The basis for these requirements is identical to that described in 9.18.1 except that the
wire pair crosstalk characteristics are such that there is great crosstalk coupling of
longitudinal voltages. Thus, there is a lower limit on both the in-band and out-of-band
longitudinal LADC voltages than the metallic LADC voltages.
8
9
10
9.19.2 Purpose
11
12
13
9.19.3 Equipment
(1)
Applicable loop simulator SEL#4.
14
(2)
Bandpass filter SEL#9.
15
(3)
Bandpass filter SEL#11.
16
(4)
Companion terminal equipment SEL#15.
17
(5)
Digital sampling storage oscilloscope SEL#24.
18
(6)
Spectrum Analyzer SEL#34.
19
To verify that the EUT does not apply excessive longitudinal power to the network.
Note: Refer to subclause 5.5 for equipment details.
20
21
22
23
24
25
26
27
28
29
30
31
9.19.4 Equipment States Subject to Test
32
9.19.5 Procedure
Active and transmitting data.
Note: Terminal equipment may require special attention to ensure it is properly configured for this
test. For example, if the equipment would normally be connected to ac-power ground, coldwater-pipe ground, or if it has a metallic or partially metallic exposed surface, then these points
are to be connected to the test ground plane. Similarly, if the EUT provides connections to
other equipment through which ground may be introduced to the equipment, then these points
are to be connected to the test ground plane. Equipment that does not contain any of these
potential connections to ground is to be placed on a conductive plate which is connected to the
test ground plane (see comment (3)); this applies to both non-powered and ac-powered
equipment.
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Note: Refer to subclause 4.5.7.5 to 4.5.7.8 for applicable test conditions.
2
3
4
9.19.6 Frequencies Below 4 kHz ANSI/TIA-968-A, 4.5.6.3.1
5
6
(2) Cause the EUT to transmit an output signal in accordance with subclauses 4.5.7.6
and 4.5.7.7 of ANSI/TIA-968-A.
7
(3)
Record the maximum spectrum analyzer reading in the test band.
8
(4)
Repeat step (2) and step (3) for all possible states.
(1)
9
Connect the EUT to the test circuit of Figure 9.19-1.
Note: The remaining steps are only applicable to four-wire EUTs.
10
(5)
Connect the EUT to the test circuit of Figure 9.19-2.
11
(6)
Repeat step (2) through step (4).
12
13
Note: The measured result is to be corrected (+3.1) dB for the voltage divider relationship of the
termination.
14
15
16
17
9.19.7 8 kHz Bands over the Frequency Range of 4 kHz to 270 kHz ANSI/TIA-968A, 4.5.6.3.2
(1)
Connect the EUT to the test circuit Figure 9.19-3.
18
(2)
Select R1=R2=150 ohms and R3=425 ohms.
19
20
(3) Cause the EUT to transmit an output signal in accordance with subclause 4.5.7.6
and 4.5.7.7 of ANSI/TIA-968-A.
21
22
(4) Measure the rms voltage averaged over 100 ms with a bandwidth of 8 kHz covering
the frequency range of 4 kHz to 16 kHz.
23
24
25
26
27
Note: The measured result is to be corrected for the voltage divider relationship of the termination.
Adjustment is (+1.4) dB.
(5)
Compare the results with the allowed limit for each 8 kHz band having a center
frequency between 8 kHz and 12 kHz, and record the measured value having the
smallest margin relative to the allowed limit and its frequency.
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(6)
2
3
(7) Cause the EUT to transmit an output signal in accordance with subclause 4.5.7.6
and 4.5.7.7 of ANSI/TIA-968-A.
4
5
(8) Measure the rms voltage averaged over 100 ms with a bandwidth of 8 kHz covering
the frequency range of 8 kHz to 46 kHz.
6
7
Select R1=R2=67.5 ohms and R3=56.3 ohms.
Note: The measured result is to be corrected for the voltage divider relationship of the termination.
Adjustment is (+4.0) dB.
8
9
10
(9)
Compare the results with the allowed limit for each 8 kHz band having a center
frequency between 12 kHz and 42 kHz, and record the measured value having the
smallest margin relative to the allowed limit and its frequency.
11
12
(10) Measure the rms voltage averaged over 100 ms with a bandwidth of 8 kHz covering
the frequency range 38 kHz to 270 kHz.
13
14
Note: The measured result is to be corrected for the voltage divider relationship of the termination.
Adjustment is (+4.0) dB.
15
16
17
(11)
18
(12)
19
Record the highest measured value and its associated frequency and any test
results that exceed (-62) dBV for center frequencies in each 8 kHz band between 42
kHz and 266 kHz.
Repeat step (2) through step (11) for all operating conditions.
Note: The remaining steps are only applicable to four-wire EUTs.
20
(13)
Connect the EUT to the test circuit of Figure 9.19-4.
21
(14)
Repeat step (2) through step (12) for all operating conditions.
22
23
24
9.19.8 RMS Voltages at Frequencies Above 270 kHz 4.5.6.3.3
(1)
Connect the EUT to the test circuit of Figure 9.19-5.
25
(2)
Select the 270 kHz to 6 MHz bandpass filter.
26
(3)
Set the digital oscilloscope to provide:
27
(a)
2 microseconds (µs) per sample;
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(b)
Trigger at (-25) dBV;
2
(c)
Accumulate mode;
3
(d)
Vertical scale 0 mV to 100 mV full height.
4
5
Note: If the baseline contains 1000 points then a single trace will take 2 ms.
6
(4)
Program the oscilloscope to accumulate 10 traces.
7
8
(5)
Cause the EUT to transmit an output signal in accordance with subclauses 4.5.7.6
and 4.5.7.7 of ANSI/TIA-968-A.
9
10
(6)
Record the value of the largest peak measured and convert to Vrms by multiplying by
0.707.
11
Note: The remaining steps are only applicable to four-wire EUTs.
12
(7)
Connect the EUT to the test circuit of Figure 9.19-6.
13
(8)
Repeat step (2) through step (6).
14
15
Note: The measured result of step (7) is to be corrected (+4) dB for the voltage divider relationship of
the termination.
16
17
18
19
9.19.9 Alternative Methods
20
21
22
9.19.10 Suggested Test Data
23
(2) Voltage levels, measured or calculated.
24
(3) Equipment state.
None suggested.
(1) Center frequencies measured or frequency band measured.
25
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2
3
4
5
9.19.11 Comments
(1)
Reference ANSI/TIA-968-A, subclauses 4.5.7.5 through 4.5.7.8 for further
information.
6
(2)
A pseudorandom signal source may be used for testing.
7
8
9
10
(3)
EUT that is not normally grounded should be set in its normal position directly on a
conductive plate. It is recommended that the overall area of the conductive plate be
at least 50% greater than that of the base of the EUT. This represents the closest
proximity to ground that is likely to be encountered by the EUT.
11
12
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2
3
4
5
6
Note 1.
Ensure proper operation of the EUT while the pair under test is not connected to the
companion terminal equipment.
7
Note 2.
The 300 ohm resistors should be adequately matched.
8
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
9
10
11
Figure 9.19-1. LADC Longitudinal 10 Hz - 4 kHz, T&R
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2
3
4
5
6
Note 1.
Ensure proper operation of the EUT while the pair under test is not connected to the
companion terminal equipment.
7
Note 2.
The 300 ohm resistors should be adequately matched.
8
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
9
10
11
Figure 9.19-2. LADC Longitudinal 10 Hz to 4 kHz, T1 & R1
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2
3
4
5
6
7
8
Notes:
(1)
Ensure proper operation of the EUT while the pair under test is not connected to the companion
terminal equipment.
9
(2)
The resistors R1 and R2 should be adequately matched.
10
(3)
Refer to the figures of clause 1 of ANSI/TIA-968-A.
11
12
13
14
15
Figure 9.19-3. LADC Longitudinal 4 kHz to 270 kHz, T & R
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2
3
4
5
6
7
8
9
10
11
Note 1.
Ensure proper operation of the EUT while the pair under test is not connected to the
companion terminal equipment.
12
Note 2.
The resistors R1 and R2 should be adequately matched.
13
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
14
15
16
17
18
Figure 9.19-4. LADC Longitudinal 4 kHz to 270 kHz, T1 & R1
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2
3
4
5
6
Note 1.
Ensure proper operation of the EUT while the pair under test is not connected to the
companion terminal equipment.
7
Note 2.
The 67.5 ohm resistors should be adequately matched.
8
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
9
10
11
12
Figure 9.19-5. LADC Longitudinal 270 kHz to 6 MHz, T & R
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2
3
4
5
6
Note 1.
Ensure proper operation of the EUT while the pair under test is not connected to the
companion terminal equipment.
7
Note 2.
The 67.5 ohm resistors should be adequately matched.
8
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
9
10
11
12
Figure 9.19-6. LADC Longitudinal 270 kHz to 6 Mhz, T1 & R1
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2
3
4
5
6
7
8
9.20 Pulse Repetition Rate, Subrate/PSDS, ANSI/TIA-968-A, 4.5.8.1.1 and 4.5.8.3.1
9.20.1 Background
The transmitted pulse repetition rate needs to be the same as the rate used to create
the pulse template. This ensures proper pulse width for comparison with the pulse
templates defined in ANSI/TIA-968-A, 4.5.8.1.1 for Subrate signaling and 4.5.8.3.1 for
PSDS Type II or III signaling.
9
10
11
12
13
9.20.2 Purpose
14
15
16
9.20.3 Equipment
(1)
Data generator SEL#18.
17
(2)
Spectrum analyzer SEL#34.
To verify that the EUT will synchronize its output clock rate as required. Subrate
equipment should synchronize with the network clock rate and PSDS equipment should
synchronize with its internal setting.
18
Note: Refer to subclause 5.5 for equipment details.
19
20
21
22
23
9.20.4 Equipment States Subject to Test
24
25
26
27
9.20.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.20-1. Both the transmit pair and
receive pair should be terminated with 135 ohms.
28
29
(2)
A) For Subrate equipment, transmit a digital signal into the receive tip and ring leads
of the EUT at the appropriate data rate.
30
31
The EUT should be active and transmitting a digital signal. This test should be
performed at each of the data rates at which the equipment under test is capable of
operating.
B) For PSDS equipment, configure the EUT to generate the appropriate data rate for
test.
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(3)
Measure the resultant pulse rate on the transmit tip and ring leads.
2
3
4
(4)
Verify that the output pulse rate of the EUT is the same as the data rate input on the
receive tip and ring leads for Subrate equipment or as configured for PSDS
equipment.
5
(5)
Repeat steps (2) through (4) as necessary for each data rate supported by the EUT.
6
7
8
9
10
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12
13
9.20.6 Alternative Method
14
15
16
9.20.7 Suggested Test Data
17
18
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20
21
22
9.20.8 Comment
(1)
Performance of this test is equally possible with a dual-trace oscilloscope by
connecting it to the equipment so that one channel displays the signal input to the
equipment under test while the other channel displays the output signal. The output
of the equipment under test is synchronous with the input if there is no horizontal
movement (walking) of the transmitted pulse display in relation to the received pulse
display when the scope is set to trigger on the received signal.
The measured pulse repetition rate for each available data rate.
If a pulse counter is used in place of the spectrum analyzer to make this measurement,
ensure that the measured output consists of an all-ones signal so that a proper reading
is taken.
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NOTE 2
1
2
3
4
Note 1.
The spectrum analyzer should provide a balanced input.
5
6
Note 2.
For PSDS Type II and III equipment, T1 and R1 leads and the Data Generator are not
used.
7
8
9
10
Figure 9.20-1. Subrate, Pulse Repetition Rate
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9.21 Encoded Analog Content ANSI/TIA-968-A 4.5.8.1.2, 4.5.8.4, 4.5.8.2.5, 4.5.10
3
4
5
6
7
8
9
10
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27
9.21.1 Background
28
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30
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32
9.21.2 Purpose
33
34
35
9.21.3 Equipment
(1)
Companion terminal equipment SEL#15.
36
(2)
Multiplexer/demultiplexer SEL#32.
37
(3)
True rms AC voltmeter SEL#40.
Encoded analog content refers to the digital representation of analog signals encoded in
a digital bit stream. Encoding consists of sampling the analog waveform at timed
intervals and assigning a unique binary code to represent each quantized amplitude.
These binary codes, when decoded, are then used to create an analog waveform that
represents the original. Normally, decoding results in the same analog level for each
sample that was originally encoded. This process is known as zero-level encoding and
decoding of an analog waveform.
Encoded analog limits ensure that analog signal power and billing protection
requirements are met at the digital interface so that no further analog limitations are
required downstream where digital to analog conversion and connection to the analog
network takes place. If not limited, the analog signals could crosstalk into other pairs in
the same cable or overload telephone company frequency division multiplex systems
(carrier systems). Generally, analog levels decoded by a zero-level decoder are 3 dB
lower than levels from analog terminal equipment. Actually, the limit is the same for
both cases at the telephone company CO, but analog loops have a nominal 3 dB loss
while digital facilities are lossless in analog terms.
Digital terminal equipment can be designed to assure that encoded analog signal power
requirements are met. If not, it is to be connected to equipment that either is approved
for compliance with the encoded analog limits or is used under a condition that encoded
analog content will not be used or will be properly adjusted.
To verify the maximum equivalent power of the encoded analog content of the
transmitted digital signal.
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Note: Refer to subclause 5.5 for equipment details.
2
3
4
5
9.21.4 Equipment States Subject to Test
6
7
8
9
9.21.5 Procedure
The EUT is to be active and transmitting encoded analog signals.
(1)
Connect the EUT to the test circuit of Figure 9.21-1. As shown, two types of signals
may be transmitted:
10
11
(a)
Internally generated signals that are generated directly in digital form but
which are intended for eventual conversion to analog form;
12
13
(b)
Internally generated analog signals that are converted to digital format for
eventual reconversion to analog form.
14
15
(2)
For signals of type (a) or type (b) as described above, cause the equipment to
generate each of the possible signals.
16
17
18
(3)
Record the power of each of the transmitted signals as measured at the output of the
zero-level decoder or companion terminal equipment. The recorded level should be
the maximum obtainable level when averaged over any 3-second interval.
19
20
21
22
23
9.21.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 9.21-1 and replace the true rms AC
voltmeter with a signal analyzer (SEL#56).
24
(2)
Set the signal analyzer to measure the following:
25
(a)
Signal level in dBm, 600 ohms.
26
(b)
Averaging over 3 second.
27
(c)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
28
29
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
(3)
For signals of type (a) or type (b) as described in subclause 9.21.5, cause the
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equipment to generate each of the possible signals.
2
(4)
Measure and record the maximum signal power level in dBm.
3
(5)
Repeat step (2) and step (3) for other internally generated signals.
4
5
6
7
8
9.21.7 Suggested Test Data
The signal measured and the power reading measured.
9
10
11
9.21.8 Comments
(1)
The measurement is to be in dBm with respect to 600 ohms.
12
13
(2)
Both the network control signals and all internally generated signals is to be
measured.
14
15
16
(3)
For readings requiring averaging, a meter incorporating this function may be used
to make the measurement, or the average may be calculated using the maximum
duty cycle within the 3-second time period.
17
18
(4)
The test procedures in this subclause apply to interfaces that are covered in
ANSI/TIA-968-A subclauses 4.5.8.1.2, 4.5.8.2.5, 4.5.8.3 and 4.5.8.4.
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2
3
Note: For PSDS type II, III and BRA-U equipment, T1 and R1 leads are not used.
Figure 9.21-1. Encoded Analog Content
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9.22 Equivalent PSD For Maximum Output, Subrate – ANSI/TIA-968-A, 4.5.8.1.3
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3
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7
8
9
10
11
9.22.1 Background
12
13
14
15
16
9.22.2 Purpose
17
18
19
9.22.3 Equipment
This subclause provides a test procedure to measure power spectral density (PSD)
against the alternate subrate requirements specified in ANSI/TIA-968-A, subclause
4.5.8.1.3. The PSD requirements were established as an alternate method to the
subrate pulse requirements to minimize crosstalk interference with other equipment that
share the same cable binder. Crosstalk interference is widely recognized as a form of
third party harm.
To verify that the PSDs generated by subrate devices are below the established masks
(as applicable).
(1)
Spectrum analyzer SEL# 57.
20
(2)
Data generator SEL# 18.
21
(3)
135:50 ohm balun transformer SEL# 65.
22
23
Note: Refer to subclause 5.5 for equipment details.
24
25
26
27
28
29
9.22.4 Equipment States Subject to Test
The EUT is to be active and continuously transmitting pseudo-random test pattern at
each applicable line baud rate.
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2
3
9.22.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.22-1.
4
5
(2)
Configure the EUT to transmit a pseudo-random test pattern at the desired baud
rate.
6
(3)
Measure and record the PSD on the spectrum analyzer with the following settings:
7
8
9
10
11
12
13
14
15
16
17
18
19
20








(4)
Set the RES BW to the closest value less than 0.1 times the baud rate (or
lower if desired).
Set the VIDEO BW and to 0.1 times the resolution bandwidth (or lower).
dB/div: 10 dB
Reference level: as required to capture the entire PSD
Attenuation or range: Set for minimum without overload
Start frequency: ½ the EUT baud rate
Stop frequency: 20 times the baud rate unless 20 times the baud rate is less
than 80 kHz, in which case set the stop frequency to 80 kHz.
Marker Function: Noise dBm/Hz
Repeat Step (2) and Step (3) for all baud rates at which the equipment is capable of
operating.
21
22
23
24
25
9.22.6 Alternative Methods
26
27
28
9.22.7 Suggested Test Data
29
30
31
9.22.8 Comments
(1)
The PSD measurements should be noise measurements in dBm/Hz.
32
33
(2)
Take into account applicable correction factors for the balun over the bandwidth of
the measurement.
None suggested.
(1)
Plots of the PSD for each baud rate with the limit line shown on each graph
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Transmit
Pair
135Ω:50Ω
Balun
Spectrum
Analyzer
EUT
Receive
Pair
Data
Generator
R
Note: The value of R is to be selected such that R plus the source impedance of the data generator
will equal 135 ohms.
Figure 9.22-1. Subrate Signal Power
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2
3
9.23 Average Power, Subrate, Non-Secondary Channel Rates, Secondary Channel
Rates ANSI/TIA-968-A, 4.5.8.1.4 and 4.5.8.1.5
4
5
6
7
8
9
10
9.23.1 Background
11
12
13
14
9.23.2 Purpose
15
16
17
9.23.3 Equipment
18
(2)
19
(1)
The signal power of subrate devices is limited to minimize crosstalk interference with
other equipment that share the same cable binder. Crosstalk interference is widely
recognized as a form of third party harm.
To verify that the signal power level transmitted to the network is properly limited.
(1)
20
21
True rms AC voltmeter SEL# 41.
Data generator SEL# 18.
135 ohm, 1 %, non-inductive resistor.
Note: Refer to subclause 5.5 for equipment details.
22
23
24
25
26
9.23.4 Equipment States Subject to Test
27
28
29
9.23.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.23-1.
30
(2)
Configure the EUT to transmit a pseudo-random test pattern at the desired line rate.
31
(3)
Measure and record the signal power level in dBm.
The EUT is to be active and continuously transmitting a pseudo-random test pattern at
each applicable line rate.
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2
3
Repeat Step (2) and Step (3) for all pulse rates at which the equipment is capable of
operating.
4
5
6
7
8
9
10
11
12
13
14
9.23.6 Alternative Methods
15
16
17
9.23.7 Suggested Test Data
(1)
Signal power level
18
(2)
(2) Line rate as applicable
19
20
21
22
9.23.8 Comments
The total signal power may also be calculated by integrating the PSD over the operating
band. This task consists of measuring the PSD over the operating band using a
resolution bandwidth of 0.1 times the line rate at discrete frequencies with a stepped
interval of 0.1 times the line rate. The individual PSD readings are then converted to
power readings by multiplying the PSD (in terms of watts/Hz) by the resolution
bandwidth used. This results in a power level for each resolution bandwidth window.
These are then summed over the operating band to give the total power. The PSD
measurement procedure is given in 9.22.4.
(1)
If the AC voltmeter has its dBm scale referenced to 600 ohm, correct the
measurement to account for the measurement impedance of 135 ohm.
Transmit
Pair
135Ω
EUT
Receive
Pair
True
RMS
Voltmeter
Data
Generator
R
23
24
25
Note: The value of R is to be selected such that R plus the source impedance of the data generator
will equal 135 ohm.
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2
3
Figure 9.23-1. Subrate Signal Power
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2
9.24 Pulse Template, Subrate/PSDS ANSI/TIA-968-A, 4.5.8.1.6 and 4.5.8.3.2
3
4
5
6
7
8
9
10
11
12
9.24.1 Background
13
14
15
9.24.2 Purpose
16
17
18
9.24.3 Equipment
(1)
Data generator SEL#18.
19
(2)
Digital sampling storage oscilloscope SEL#24.
Pulse templates, one for each data rate, define the pulse shape needed to minimize the
risk of crosstalk interference in telephone company transmission facilities. The single
pole filter, which provides high frequency roll-off, and the specific limits in the vicinity of
28 kHz and 76 kHz protect other services using the same telephone company cable.
Similarly, the pulse amplitude limit for the 9.6 kilobits per second (kb/s) and 12.8 kilobits
per second (kb/s) data rates are less than for other subrates because of the sensitivity
of certain loop transmission systems to crosstalk interference at the frequencies
generated.
To verify the pulse shape of the digital signal at the output of the EUT.
20
Note: Refer to subclause 5.5 for equipment details.
21
22
23
24
25
26
27
28
29
9.24.4 Equipment States Subject to Test
30
31
32
9.24.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.24-1.
33
(2)
Cause the equipment under test to transmit a digital signal which will allow the
The EUT is to be active and transmitting a data pattern which allows the recording of an
isolated pulse. An isolated pulse is a single pulse without leading or trailing pulses (i.e.,
a bit pattern of 010). The number of leading and trailing zeros which it is possible to
transmit may vary from equipment to equipment; however, at least one leading and one
trailing zero is necessary, and it is desirable to make the measurement with as many as
seven leading and seven trailing zeros.
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capture of an isolated pulse.
2
3
(3)
Record a single positive pulse on the oscilloscope, and compare the pulse to the
criteria.
4
5
(4)
Record a single negative pulse on the oscilloscope, and compare the pulse shape to
the criteria.
6
7
(5)
Repeat Step (3) and Step (4) for all pulse rates at which the equipment is capable of
operating.
8
9
10
9.24.6 Alternative Method
11
12
13
9.24.7 Suggested Test Data
(1)
A photograph or drawing of the pulse.
14
(2)
Test state.
15
(3)
Data rate.
16
17
18
19
20
9.24.8 Comments
(1)
A non-storage oscilloscope may be used in place of the storage oscilloscope. A
repetitive pattern of the isolated pulse signal should be transmitted in order to
measure the pulse shape of a single pulse (i.e., a bit pattern of 010101... ).
21
22
(2)
See Appendix A.1 for more information concerning the subrate and PSD pulse
templates.
23
(3)
Configure PSDS Type II and III equipment to transmit on a stand alone basis.
24
25
(4)
PSDS Type I is evaluated in the same manner as 56 kilobits per second (kb/s)
subrate equipment.
None suggested.
26
27
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2
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4
5
Note 1.
The oscilloscope should provide a balanced input.
6
Note 2.
PSDS Types II and III equipment do not have T1 and R1 leads.
7
8
9
10
Figure 9.24-1. Subrate and PSDS, Pulse Template.
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2
9.25 Average Power, Subrate ANSI/TIA-968-A, 4.5.8.1.7
3
4
5
9.25.1 Background
6
7
8
9
9.25.2 Purpose
The long term average power needs to be limited to prevent crosstalk.
To verify the total output power of the digital signal transmitted by the equipment under
test.
10
11
12
9.25.3 Equipment
(1)
Data generator SEL#18.
13
(2)
True rms AC voltmeter SEL#41.
14
Note: Refer to subclause 5.5 for equipment details.
15
16
17
9.25.4 Equipment States Subject to Test
18
19
20
9.25.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.25-1.
21
(2)
Arrange the EUT to transmit a pseudorandom signal sequence (see Comment (3)).
22
(3)
Measure the power of the transmitted signal.
23
(4)
Repeat the test at all of the transmission rates of the EUT.
24
25
26
27
9.25.6 Alternative Method
28
29
9.25.7 Suggested Test Data
The EUT is to be active and transmitting a pseudorandom digital signal.
None suggested.
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2
3
The measured signal power in dBm for each transmission rate and operating state of
the EUT.
4
5
6
7
8
9.25.8 Comments
(1)
Note that the criteria is in dBm with reference to 135 ohms. Some measuring
instruments use different reference impedances. Readings made on instruments
using reference impedances other than 135 ohms should be corrected.
9
10
(2)
In order to evaluate the long term average level of the signal, measurements using a
3-second averaging time are appropriate.
11
12
13
14
15
(3)
In some cases, it may be necessary to use an external digital source. If the EUT
does not allow the transmission of the random test signal, the test may be performed
with an all-ones signal being transmitted. When transmitting a digital signal of allones, the average signal power can be calculated by subtracting the averaging factor
(3 dB) from the measured signal power.
16
17
(4)
A spectrum analyzer may be used to measure the individual spectral components of
the signal, and the sum of the powers of these signals may be taken.
18
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4
5
6
7
8
Note: The voltmeter should provide a balanced input.
Figure 9.25-1. Subrate, Average Power
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9.26 Pulse Repetition Rate, 1.544 Mb/s ANSI/TIA-968-A, 4.5.8.2.1
3
4
5
9.26.1 Background
6
7
8
9.26.2 Purpose
Improper pulse rates cause interference with other users in higher level bit streams.
To verify the free-running pulse repetition rate of the EUT.
9
10
11
9.26.3 Equipment
(1)
Data generator SEL#18.
12
(2)
Spectrum analyzer SEL#34.
13
14
Note: Refer to subclause 5.5 for equipment details.
15
16
17
9.26.4 Equipment States Subject to Test
18
19
20
21
9.26.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.26-1. Both the transmit pair and the
receive pair should be terminated in the proper resistive loads.
22
23
(2)
Arrange the equipment in accordance with the instruction manual so that it generates
a free-running signal.
24
(3)
Measure the resultant pulse repetition rate.
The EUT is to be active and transmitting a free running signal.
25
26
27
28
9.26.6 Alternative Methods
29
30
9.26.7 Suggested Test Data
None suggested.
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(1)
Type of signal.
2
(2)
Measured pulse repetition rate.
3
4
5
6
9.26.8 Comments
(1)
As many "ones" as possible should be transmitted while making the measurement to
increase the energy of the signal at the pulse frequency.
7
8
(2)
As an alternative, use a PCM decoder which provides a 1.544 MHz clock which is
derived from the output of the EUT by the decoder.
9
10
11
12
13
Figure 9.26-1. 1.544 megabits per second (Mb/s), Pulse Repetition Rate
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9.27 Pulse Template, 1.544 Mb/s ANSI/TIA-968-A, 4.5.8.2.2, 4.5.8.2.3
3
4
5
6
7
8
9
10
11
12
13
14
9.27.1 Background
15
16
17
18
19
9.27.2 Purpose
20
21
22
9.27.3 Equipment
(1)
DS1 transmission set (SEL#25) if required.
23
(2)
Digital sampling storage oscilloscope (SEL#24).
24
25
Line Build Out (LBO) controls the pulse shape in order to present a compatible signal
input for some T1 line repeaters or to limit crosstalk on non-repeatered route junctions.
Subclause 4.5.8.2.3 requires that the equipment provide an option to set the amplitude
of the T1 signal presented to the network consistent with three values of LBO. The
carrier advises the customer on the LBO setting at the time of installation. LBO
synthesizes cable loss within the terminal equipment and is expressed as a minimum
loss at 772 kHz. LBO’s of 0 dB, 7.5 dB, and 15 dB correspond to the Pulse Template
Options of A, B, and C respectively. Testing and showing compliance with the Pulse
Template Options described in subclause 4.5.8.2.2 also satisfies the requirements in
subclause 4.5.8.2.3 for the Adjustment of Signal Voltage.
To verify that the equipment is capable of delivering the Option A, B, and C output
pulses and that the rise and fall times and the amplitude of an isolated pulse meets the
pulse template criteria.
Note: Refer to subclause 5.5 for equipment details.
26
27
28
29
30
31
32
33
9.27.4 Equipment States Subject to Test
34
35
9.27.5 Procedure
The EUT is to be active and transmitting a data pattern which allows for the recording of
an isolated pulse. An isolated pulse is a single pulse without leading or trailing pulses.
The number of leading and trailing zeros that is possible to transmit may vary from
equipment to equipment. However, at least four leading and one trailing zero is
necessary to make an accurate measurement. The 1-in-8 test pattern satisfies the
requirement for leading and trailing zeros.
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(1)
Connect the EUT to the test circuit of Figure 9.27-1.
2
3
(2)
Verify that the output pulse options are selectable at the time of installation, and
select output pulse option "A" (0 dB loss at 772 kHz).
4
5
6
7
(3)
Cause the equipment under test to generate a pattern, which will allow for the
capture of an isolated pulse. This may be achieved by putting the equipment in
loopback and using the DS1 transmission set to send a suitable test pattern or by
causing the equipment to send the test pattern using its internal generator.
8
9
(4)
Record a single positive pulse on the oscilloscope, and compare the pulse shape to
the template criteria.
10
11
(5)
Record a single negative pulse on the oscilloscope, and compare the pulse shape to
the template criteria.
12
13
(6)
Repeat Step (3) through Step (5) for output pulse options "B" (7.5 dB loss at 772
kHz) and "C" (15 dB loss at 772 kHz).
14
15
16
17
18
9.27.6 Alternative Methods
19
20
21
9.27.7 Suggested Test Data
(1)
The pulse option.
22
(2)
Plots of the isolated pulses relative to the pulse mask templates.
23
24
25
26
27
28
9.27.8 Comments
(1)
A non-storage oscilloscope may be used in place of the storage oscilloscope. A
repetitive pattern of the isolated pulse signal should be transmitted in order to make
the measurement. In this situation, an unframed signal or loopback of a controlled
input signal may be transmitted to capture the proper pulse.
29
30
(2)
See Appendix A.2 for more information concerning the 1.544 megabits per second
(Mb/s) pulse templates.
31
32
(3)
The LBO of the DS1 transmission set, if used, should be set to a minimum of 15 dB
to minimize coupling into the equipment’s transmit pair to minimize distorting the
If the equipment is capable of generating the test pattern internally and can operate
using internal timing, then the test may be performed without the DS1 transmission set.
In this case, terminate the receive pair with a 100 ohm resistive load.
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
EUT’s signal.
See Note
T
R
EUT
100
T1
Oscilloscope
DS1 Transmission
Test Set
R1
Note: The oscilloscope should provide a high-impedance balanced input.
Figure 9.27-1. 1.544 Mb/s, Pulse Template connection diagram
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9.28 Output Power, 1.544 Mb/s ANSI/TIA-968-A, 4.5.8.2.4
9.28.1 Background
The long-term average power for pulse option "A" (0 dB loss at 772 kHz)is limited to
control crosstalk interference. The limitation is in the 3-kHz band around the 772-kHz
envelope of the bipolar signal and the 1.544-MHz pulse repetition rate where the
majority of the energy of an all-ones unframed signal is located.
9
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9.28.2 Purpose
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9.28.3 Equipment
(1)
Data generator SEL#18.
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(2)
Spectrum analyzer SEL#34.
To verify the output power of an all-ones unframed digital signal in the 3 kHz bands
centered at 772 kHz and 1.544 MHz is within the stated limitations.
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18
Note: Refer to subclause 5.5 for equipment details.
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9.28.4 Equipment States Subject to Test
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9.28.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.28-1 and select pulse option "A" (0 dB
loss at 772 kHz).
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(2)
Cause the equipment to transmit the unframed all “ones” digital signal.
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(3)
With a measurement bandwidth of 3 kHz, measure the signal power at 772 kHz.
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(4)
With a measurement bandwidth of 3 kHz, measure the signal power at 1.544 MHz.
Active and transmitting an unframed all "ones" digital signal. If transmission of an
unframed all "ones" signal is not possible, then the readings taken are to be corrected
for the data pattern that is transmitted. This correction is covered in the alternative
procedure of subclause 14.2.4.6.
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9.28.6 Alternative Method
(1)
Connect the EUT to the test circuit of Figure 9.28-1, and measure the amplitude of a
positive and negative pulse. These pulses should have both leading and trailing
pulses.
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(2)
Calculate the power at 772 kHz in dBm using the formula:
The following method of measurement may be used when an unframed all-ones
condition cannot be achieved. The equipment should be configured to be transmitting
idle channels with a stable bit pattern; that is, no signal input to any channel. The
transmitted pulse level should be set for option "A." Note the pulse density of the
transmitted signal. This may be determined by examination of the transmitted bit
stream.
2
4
10 * log  * v*.707

 30
P772k ( dBm) 
200
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P
772k
( dBm )  6.53  ( 20 x log( V ))
Where V is the arithmetic average of the absolute value of the pulse amplitudes found in
Step (2).
(4)
Measure the signal power at 1.544 MHz using the method described in subclause
14.2.4.6 and calculate the all-ones power by adding the appropriate correction factor
for the ones density of the transmitted signal from Table 9.28-1.
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Table 9.28-1. Correction Factors for 1.544 megabits per second (Mb/s) Output
Power
3
4
Ones
Density (%)
12.5
25.0
37.5
50.0
62.5
75.0
87.5
100.0
Correction Factor (dB)
18.1
12.0
8.5
6.0
4.1
2.5
1.1
0.0
5
6
7
8
9
9.28.7 Suggested Test Data
The measured power at 772 kHz and at 1.544 MHz in dBm with respect to 100 ohms.
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9.28.8 Comments
(1)
The reading is to be in dBm referenced to 100 ohms. If the measuring instrument
uses a reference impedance other than 100 ohms, the measurement is to be
corrected.
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(2)
A variable bandpass filter and true rms voltmeter may be used in place of the
spectrum analyzer to make the measurement.
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(3)
A frequency selective voltmeter may be used in place of the spectrum analyzer to
make the measurement.
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(4)
For accuracy, the 3 kHz bandpass measurement should be made with a filter having
a sharp rolloff; however, the filter should not cause attenuation of the signal being
measured. If a measurement bandwidth of 3 kHz is not obtainable, care should be
taken that signal power in the desired band is not excluded for measurement
bandwidths less than 3 kHz and that additional signals are not included in the
measurement for bandwidths greater that 3 kHz.
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See Note
T
R
EUT
T1
R1
Spectrum
Analyzer
100
DS1 Transmission
Test Set
Note : The spectrum analyzer should provide a high-impedance, balanced input.
Figure 9.28-1. 1.544 megabits per second (Mb/s), Output Power
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9.29 Unequipped Sub-rate Channels ANSI/TIA-968-A, 4.5.8.2.6
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9.29.1 Background
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9.29.2 Purpose
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9.29.3 Equipment
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9.29.4 Equipment States Subject to Test
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9.29.5 Procedure
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9.29.6 Alternative Methods
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9.29.7 Suggested Test Data
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9.29.8 Comments
For connections to 1.544 megabits per second (Mbps) digital services, the permissible
code words for unequipped µ255 encoded sub-rate channels of terminal equipment
connected to 1.544 Mbps digital services, including ISDN PRA, are limited to those
corresponding to signals of either polarity, of magnitude equal to or less than X48,
where code word Xn is derived by:
Xn = (255 - n) base 2
-Xn = (127 - n) base 2
To verify that the equipment complies with the requirements of this subclause under all
operating conditions.
None suggested.
Not applicable.
None suggested.
None suggested.
Provide an attestation that states that the design of the EUT complies with the
requirement of this subclause under all operating conditions.
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None suggested.
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9.30 Conditioning ADSL EUT to Transmit Continuously
9.30.1
General
This subclause provides a suggested test procedure to measure aggregate signal
power, power spectral density (PSD), and longitudinal output voltage (LOV) for ADSL
modems (ADSL ATU-R or similar CPE) against the applicable requirements specified in
ANSI Standard ANSI/TIA-968-A-2002 including requirements up to and including those
set out in ANSI/TIA-968-A-3.
9.30.2
Conditioning the EUT to Transmit Continuously
To properly measure aggregate signal power, PSD, and LOV, condition the EUT to
transmit at its highest signal power level and line rate as allowed by the respective PSD
mask without a sustained connection to companion equipment. The method of testing
with a companion device is impractical for ADSL equipment since the companion (ATUC) equipment may present excessively high signal levels at frequencies at which the
upstream PSD mask demands very low PSD levels. The amount of attenuation
required to reduce the companion equipment’s signals below the upstream mask would
be excessive to permit the link to come up at the maximum upstream line rate. This is
because ADSL equipment automatically reduces the line rate over long loops to
maintain an acceptable level of performance. Test ADSL modems that support
extended upstream operation against all of the spectral masks for all the operational
modes that they support. The extended upstream mask 1 (ANSI/TIA-968-A-3, 4.5.9.1.3)
should be used for ADSL2+.
There are two possible methods to achieve the required state for the ADSL modem.
One method involves a test mode whereby the EUT’s transmitter is forced to enter the
showtime state, at a maximum PSD level and line rate allowed by the PSD mask,
without going through a training sequence. Showtime refers to the state where the
ADSL modem is transmitting a pseudo-random data pattern continuously. The other
technique first involves bringing the link up over an artificial line whose characteristics
effectively force the EUT into its maximum signal power and line rate allowed by the
PSD mask. Next, the EUT is strapped or conditioned to disable retrains so that once
the showtime state has been achieved, the EUT may be disconnected from the artificial
line and connected to a 100 ohm measurement termination. The artificial line may be
either a commercial telephone line simulator or a simple 100 ohm balanced attenuator
pad. In either case, the amount of through transmission attenuation is set to maximize
the EUT’s transmit power and bandwidth subject to the PSD mask constraints. This is
necessary as most ATU-R’s utilize an adaptive transmit power scheme where power is
cut back under short loop conditions. By the same token, if the line attenuation is
excessive, then the link will not have sufficient margin to come up at the desired line
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rate. The amount of line attenuation will vary from one vendor’s CPE to another and
even with the same CPE if the start up margin is changed.
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9.31 Total Average Power, ADSL Terminal Equipment ANSI/TIA-968-A-3,
4.5.9.1.1
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9.31.1
Background
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9.31.2
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16
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9.31.3
(1)
True rms AC voltmeter SEL#41.
18
(2)
100 ohm, 1 %, non-inductive resistor.
The aggregate signal power, or total power, of the ADSL modem is limited to minimize
near end crosstalk (NEXT) with other DSL systems that share the same cable binder.
Crosstalk is widely recognized as a form of third party harm and represents the principal
impairment to many DSL systems.
Purpose
To verify that the signal power level transmitted to the network is properly limited.
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Equipment
Note: Refer to subclause 5.5 for equipment details.
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21
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9.31.4
Equipment States Subject to Test
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9.31.5
(1)
Condition the EUT to transmit at it highest upstream signal power level and line rate
as described in 9.31.2.
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(2)
Connect the EUT to the test circuit of Figure 9.31-1.
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(3)
Measure and record the signal power level in dBm. The level should be averaged
over a time span of at least 10 seconds if shorter term variations are observed.
Transmitting continuously at its highest signal power and upstream line data rate
allowed by the PSD mask. For ADSL modems that support extended upstream
operation, consider each supported Extended Upstream [EU] mask number.
Procedure
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9.31.6
Alternative Methods
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9.31.7
(1)
Signal Power Level.
15
(2)
Line Data Rate and Baud Rate if applicable.
The total signal power may also be calculated by integrating the PSD over the operating
band. This task consists of measuring the PSD over the operating band using a 10 kHz
resolution bandwidth at discrete frequencies with a stepped interval of 10 kHz. The
individual PSD readings are then converted to power readings by multiplying the PSD
(in terms of watts/Hz) by the 10 kHz resolution bandwidth. This results in a power level
for each 10 kHz window. These are then summed over the operating band to give the
total power. The PSD measurement procedure is given in 9.32.5.
Suggested Test Data
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9.31.8
Comments
If the AC voltmeter has its dBm scale referenced to 600 ohms, then a use a correction
factor of 7.8 dB added to the displayed reading to account for the measurement
impedance of 100 ohms. It is recommended that the voltmeter provide a highimpedance balanced input particularly if the EUT has intentional paths to ground.
Figure 9.31-1. Average Signal Power
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9.32 Power Spectral Density, ADSL Terminal Equipment ANSI/TIA-968-A-3,
4.5.9.1.2, 4.5.9.1.3
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9.32.1
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9.32.2
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9.32.3
(1)
Spectrum analyzer SEL#57.
27
(2)
100 ohm, 1 % non-inductive resistor.
28
(3)
Differential amplifier with 10X passive probe set and built in LPF SEL#58.
29
(4)
100:50 ohm balun transformer SEL#59.
30
(5)
10 dB, 50 ohm pad SEL#60
31
(6)
500 kHz High-Pass Filter SEL#61
32
33
Background
As is the case for the ADSL modem’s total power, its PSD is limited to minimize
crosstalk. PSD is limited by the imposition of a PSD mask, which specifies a limit as a
function of frequency. The mask permits a reasonable level in the operating band while
restricting the ADSL modem’s PSD below the operating band to protect POTS and
above the operating band both to minimize interference both with the downstream
spectrum as well as other DSL systems potentially affected by crosstalk. The mask
presents measurement challenges because it specifies such a broad range of signal
levels, which can’t practically be made in a single sweep due to limitations in the
spectrum analyzer’s dynamic range. For this reason and resolution bandwidth
considerations, the mask is broken into segments. Either low-pass or high-pass filtering
techniques are employed, as necessary, to allow the spectrum analyzer to effectively
measure low PSD levels in the presence of high PSD level conditions associated with
the operating band.
Purpose
To verify that the PSD is below the mask.
Equipment
Note: Refer to subclause 5.5 for equipment details.
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9.32.4
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9.32.5
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Equipment States Subject to Test
Transmitting continuously at its highest signal power and upstream line data rate
allowed by the PSD mask. For ADSL modems that support extended upstream
operation, consider each supported EU mask number.
Procedure
In this document the criteria frequency range has been divided into four segments. The
number of segments chosen is dependent upon the capabilities of the test equipment.
Two test procedures have been provided for the fourth segment. Therefore the test
procedure is broken down into five subclauses.
Each frequency point in the operating band (corresponding to a measurement in a
single resolution bandwidth) of a PSD should be measured by averaging the power in
the resolution bandwidth of that frequency point for a time period of at least 2.0
seconds. For a frequency swept measurement device this means setting the sweep
time in seconds equal to at least 2 times the number of frequency points. An instrument
that has a swept average feature may be used with a faster single sweep if multiple
sweeps are averaged to yield a minimum 2 second measurement time.
Note - This 2.0 second time period is based on;
 A statistical derivation demonstrating that measurement of the average power in a given resolution
bandwidth within 0.1 dB accuracy with 99% confidence requires observation of about 9,000
transmitted symbols and,
 The slowest common signal is an ADSL tone which is at a 4 kHz rate.
A faster measurement may be obtained using a time domain measurement device as
used in the examples provided. Take a sufficient number of samples to ensure an
acceptable level of precision.
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35
9.32.5.1 Procedure for Segment 1
(1)
Condition the EUT to transmit continuously as described in subclause 9.30.2.
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(2)
Connect the EUT to the test circuit of Figure 9.32-1.
37
(3)
Set the differential amplifier for unity gain and a low-pass cut-off frequency of 10 kHz.
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(4)
Set the spectrum analyzer as follows:
Resolution bandwidth (RBW): 100 Hz
Video bandwidth: 3 Hz
Attenuation or range: Set for minimum without overload
Reference level: (-40) dBm
dB/div: 10 dB
Marker Function: Noise dBm/Hz
Limit test: On with limit line programmed with the mask’s peak limit
Start frequency: 200 Hz
Stop frequency: 4000 Hz
Measure and record the PSD over the first segment of the mask, which covers the voice
frequency band. For extended rate ADSL modems, repeat steps 1-5 for each
supported EU mask.
Note: Adjust the PSD readings by a net correction factor of 17 dB derived from the 10X probe which
introduces 20 dB of loss and the 100:50 ohm impedance correction factor of -3 dB. The
resistor value in Figure 9.32-1 is in ohms.
19
20
21
9.32.5.2
(1)
Condition the EUT to transmit continuously as described in 9.30.2.
22
(2)
Connect the EUT to the test circuit of Figure 9.32-1.
23
(3)
Set the differential amplifier for unity gain with no filtering
24
(4)
Set the spectrum analyzer as follows:
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Procedure for Segment 2
Resolution bandwidth: 1 kHz
Video bandwidth: 30 Hz
Attenuation or range: Set for minimum without overload
Reference level: (-20) dBm
dB/div: 10 dB
Marker Function: Noise dBm/Hz
Limit test: On with limit line programmed with the mask’s peak limit
Start frequency: 4 kHz
Stop frequency: 26 kHz
Measure and record the PSD over the second segment of the mask, which covers the
frequencies between the voice band and the ADSL operating band. For extended rate
ADSL modems, repeat steps 1-5 for each supported EU mask.
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9.32.5.3
(1)
Condition the EUT to transmit continuously as described in 9.30.2.
5
(2)
Connect the EUT to the test circuit of Figure 9.32-4.
6
(3)
Set the spectrum analyzer as follows:
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Procedure for Segment 3
Resolution bandwidth: 10 kHz
Video bandwidth: 300 Hz
Attenuation or range: Set for minimum without overload
Reference level: (-20) dBm
dB/div: 10 dB
Marker Function: Noise dBm/Hz
Limit test: On with limit line programmed with the mask’s peak limit
Start frequency: 25 kHz
Stop frequency: 525 kHz
Measure and record the PSD over the third segment of the mask, which covers the
ADSL operating band on up to 525 kHz. For extended rate ADSL modems, repeat
steps 1-4 for each supported EU mask. Note that the sample PSD plot shown in Figure
9.32-5 is for a standard ADSL modem subject to the mask limitations of TIA 968-A-3
Clause 4.5.9.1.2.
23
24
25
9.32.5.4
(1)
Condition the EUT to transmit continuously as described in 9.30.2.
26
(2)
Connect the EUT to the test circuit of Figure 9.32-6.
27
(3)
Set the spectrum analyzer as follows:
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Procedure for Segment 4, PSD with 10 kHz RBW
Resolution bandwidth: 10 kHz
Video bandwidth: 300 Hz
Attenuation or range: Set for minimum without overload
Reference level: (-70) dBm
dB/div: 10 dB
Marker Function: Noise dBm/Hz
Limit test: On with limit line programmed with the mask’s peak
Start frequency: 525 kHz
Stop frequency: 30 MHz for ANSI/TIA-968-A-3, 4.5.9.1.2
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Stop frequency: 12 MHz for ANSI/TIA-968-A-3, 4.5.9.1.3
Measure and record the PSD over the fourth segment of the mask, which covers the
high frequencies above the ADSL operating band. For extended rate ADSL modems,
repeat steps 1-4 for each supported EU mask. Note that the sample PSD plot shown in
Figure 9.32-7 is for a standard ADSL modem subject to the mask limitations of TIA 968A-3 Clause 4.5.9.1.2.
Note: The 10 dB pad may be omitted if the high-pass filter can withstand high input levels without
introducing distortion products. Adjust the PSD readings to take into account losses introduced
by the balun, pad and filter.
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13
14
15
9.32.5.5
Procedure for Segment 4, PSD in a 1 MHz sliding window ANSI/TIA968-A-3 4.5.9.1.2, 4.5.9.1.3
(1)
Condition the EUT to transmit continuously as described in 9.30.2.
16
(2)
Connect the EUT to the test circuit of Figure 9.32-6.
17
(3)
Set the spectrum analyzer as follows:
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Resolution bandwidth: 10 kHz
Video bandwidth: 300 Hz
Attenuation or range: Set for minimum without overload
Reference level: (-70) dBm
dB/div: 10 dB
Marker Function: Noise dBm/Hz
Limit test: On (with limit line programmed with the mask limit for PSD in a
1 MHz sliding window).
Start frequency: 1.221 MHz for ANSI/TIA-968-A-3, 4.5.9.1.2
Stop frequency: 30 MHz for ANSI/TIA-968-A-3, 4.5.9.1.2
Start frequency: 1.411 MHz for ANSI/TIA-968-A-3, 4.5.9.1.3
Stop frequency: 12 MHz for ANSI/TIA-968-A-3, 4.5.9.1.3
(4)
Measure and record the PSD over the prescribed frequencies above the ADSL
operating band.
Note 1.
For measurements relative to ANSI/TIA-968-A-3 Clause 4.5.9.1.2, if the EUT’s PSD
exceeds the corresponding PSD limit that defines the total power in a 1 MHz sliding
window ,at any point above 1221 kHz, make measurements to calculate the total power in
a 1 MHz sliding window. This concept was discussed in 9.31.6. Verify the peak limit of -90
dBm/Hz, above 1221 kHz, is never be exceeded by any individual spectral component.
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However, noise may exceed the dashed line limit provided that the power integrated over a
1 MHz bandwidth is less than -50 dBm. As an example, the dashed line in ANSI T1.4131998 Figure 32 reaches a noise floor of -110 dBm/Hz, which over a 1 MHz band is
equivalent to -50 dBm.
5
6
7
8
9
10
11
12
13
Note 2.
For measurements relative to ANSI/TIA-968-A-3 Clause 4.5.9.1.3, if the EUT’s PSD
exceeds the mask limits at any frequency above 1411 kHz using a 10 kHz bandwidth,
then average the PSD over a 1 MHz sliding window. Averaging 100 consecutive 10 kHz
samples constrains the measurement to the proper frequency bands. For example, if a 1
MHz measurement bandwidth were used at a measurement frequency of 1411 kHz, the
spectrum analyzer may not have sufficient dynamic range to measure below the
specification limit. The measurement would include the contribution of frequencies
considerably below the center frequency. (3)
A faster measurement may be obtained
using a time domain measurement device.
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21
9.32.6
Alternative Methods
22
23
24
9.32.7
(1)
Plots of the PSD for each segment with the limit line shown on each graph
25
(2)
Line Data Rate and Baud Rate if applicable.
26
(3)
Total power or PSD in a 1 MHz sliding window as required.
A balun transformer may be used instead of the differential amplifier in subclause
9.32.5.1 as long as its frequency response and return loss are acceptable. Also, more
than one type of balun may be used to cover the entire frequency range of interest.
Suggested Test Data
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35
36
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38
9.32.8
Comments
Take care to ensure that measurement errors are kept to a minimum. Sources of error
may include the following:
Impedance deviations from the ideal 100 ohm termination
Differential amplifier loss or gain
Balun loss
Attenuator pad loss over the ideal loss
High-pass or low-pass filters’ frequency response
Limited dynamic range of the differential amplifier
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Limited amplitude accuracy of the spectrum analyzer
PSD measurement errors caused by excessively fast sweep times or not averaging
enough samples when making a swept average measurement
Figure 9.32-1. PSD Connection Diagram For Segments 1 & 2
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Figure 9.32-2. Sample PSD Plot For Segment 1
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Figure 9.32-3. Sample PSD Plot For Segment 2
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Figure 9.32-4. PSD Connection Diagram For Segment 3
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Figure 9.32-5. Sample PSD Plot For Segment 3
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Figure 9.32-6. PSD Connection Diagram For Segment 4
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Figure 9.32-7. Sample PSD Plot For Segment 4
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9.33 Longitudinal Output Voltage, ADSL Terminal Equipment ANSI/TIA-968-A-3,
4.5.9.1.4
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9.33.1
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9.33.2
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9.33.3
29
30
31
32
9.33.4
33
34
35
9.33.5
Background
Longitudinal output voltage (LOV) limits complement PSD limits by restricting the
amplitude of common mode signals much like the PSD limits restrict the amplitude of
the equipment’s differential mode signals. LOV limits are necessary as common mode
signals tend to couple more readily than differential mode signals in multi-line, twisted
pair cable plant. In other words, LOV limits are necessary to limit crosstalk. LOV limits
have been crafted to allow higher levels around the equipment’s operating band. This is
necessary as a common mode image of the desired differential mode signal results
through imbalance in the line interface, cabling and the measurement circuitry. A tighter
limit applies above the equipment’s operating band where the LOV source is usually not
associated with any signal intended to be applied to the line.
ADSL modems are required to meet certain LOV limits for voiceband terminal
equipment. These measurements should be made using the procedure set out in
subclasses 9.15 and 9.17.
Purpose
To verify that the longitudinal output voltage is below the limit.
(1)
(2)
Equipment
Spectrum analyzer SEL#34.
LOV Test fixture shown in Figure 9.33-1.
Note: Refer to subclause 5.5 for equipment details.
Equipment States Subject to Test
Transmitting continuously as described in 9.30.2..
(5)
Procedure
Condition the EUT to transmit continuously e as described in subclause 9.30.2.
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(6)
Connect the EUT to the test circuit of Figure 9.33-1.
2
(7)
Set the spectrum analyzer as follows:
3
4
5
6
7
8
9
10
11
12
13
Resolution bandwidth: 3 kHz
Video bandwidth: 300 Hz
Attenuation or range: Set for minimum without overload
Reference level: (-30) dBV
dB/div: 10 dB
Start frequency: 10 kHz
Stop frequency: 4fb Hz (as defined in ANSI/TIA-968-A-3)
Marker Function: Voltage dBV
Limit test: On with limit line programmed with the LOV limit
(8)
14
15
16
Measure and record the LOV averaging the readings over several sweeps.
Note: A resolution bandwidth (RBW) of 3 kHz is typically used as most spectrum analyzers support
this RBW.
17
18
19
20
9.33.6
21
22
23
24
25
26
9.33.7
27
28
29
30
31
32
33
34
35
9.33.8
Alternative Methods
None
Suggested Test Data
(1)
Plot of the LOV with the limit line shown
(2)
Line Data Rate and Baud Rate if applicable.
Comments
Take care in the construction of the LOV test fixture. Test leads from the fixture to the
EUT should be kept as short as possible to minimize RF ingress. The ground
connection to the fixture should be of a low inductance, kept short, and connected
directly to the chassis ground of the EUT. For EUT’s without an earth ground, a ground
plane should be used as discussed in subclause 9.15.8.
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2
3
4
Figure 9.33-1. LOV Test Fixture & Connection Diagram
5
6
7
8
Figure 9.33-2. Sample LOV Plot
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9.34 Voiceband Signal Power - Non-approved external signal sources ANSI/TIA968-A-3, 4.5.2.2
3
4
5
6
7
8
9
10
11
12
9.34.1 Background
13
14
15
16
17
9.34.2 Purpose
18
19
20
9.34.3 Equipment
(1)
Applicable loop simulator SEL#4
21
(2)
Frequency generator SEL#27.
22
(3)
True rms AC voltmeter SEL#40 (qty 2).
Approved terminal equipment or approved protective circuitry may have ports through
which external signal sources from non-approved equipment may be connected to the
network. External signal sources include music-on-hold sources, recorded
announcements, public address systems, studio radio/television patches, and so forth.
Obviously, such sources have very high play-back levels and could be under the control
of the users. To limit the signal level these sources could apply to the network, connect
them through equipment that ensures appropriate limiting of the signals. Rationale for
the specific limitations is discussed in subclause 9.1.1.
To verify compliance of the signal levels that are applied to the telephone network
through approved terminal equipment or approved protective circuitry from nonapproved external sources, other than data sources.
23
24
Note: Refer to subclause 5.5 for equipment details.
25
26
27
28
29
9.34.4 Equipment States Subject to Test
30
31
32
9.34.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.36-1.
33
(2)
Place the EUT in the off-hook state with a mid-range loop current (any current in
Test any off-hook state that transmits signals from non-approved equipment to the
PSTN.
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the range between 40 mA and 70 mA is acceptable).
2
3
(3)
Set the frequency generator to a frequency of 1000 Hz and an input level of -50
dBV. Measure the output level of the EUT.
4
5
(4)
Increase the level of the frequency generator in 1 dB steps and observe the signal
level. (See comment (2)).
6
7
(5)
Determine the category of signal power limiting of the EUT and its input overload
level value (see comment (3)).
8
9
(6)
Measure the output signal power level of the EUT when the level applied to the
EUT is the overload value determined in step (5).
10
11
(7)
Monitor the signal power at the network interface on the voltmeter while varying the
loop current.
12
13
(8)
Measure and record the maximum signal power level and the corresponding
current.
14
15
(9)
Increase the level of the test signal source to 10 dB above the level in step (6) (see
comment (4)).
16
17
(10)
Record the maximum voltage level at the network interface and verify that limiting
of the signal power level occurs (see comment (5)).
18
19
(11)
Repeat step (6) through step (10) for other frequencies in the 200 Hz to 4000 Hz
range. As a minimum, repeat the steps for 200, 500, 2000, and 4000 Hz.
20
21
22
9.34.6 Alternative Methods
23
24
25
9.34.7 Suggested Test Data
(1)
Input and output signal power levels.
26
(2)
Test frequencies.
27
(3)
Loop conditions of maximum signal power.
28
29
9.34.8 Comments
None suggested.
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(1)
All references to dBm are with respect to 600 ohms.
2
3
4
5
6
(2)
An EUT that uses a device (e.g. a thermistor) at the input to limit the signal power
may result in a voltmeter not providing a true indication of the input level increase.
This may be ascertained from a study of the schematic diagram. In such cases, or
when in doubt, the input level should be determined with the EUT disconnected from
the voltmeter.
7
(3)
There are essentially two categories of signal power limiting circuits:
8
9
10
11
12
13
(a)
Automatic Gain Control - An EUT with this type of signal power limiting has
virtually no output signal for input levels below a certain value. At some input
signal power level, the output level of the EUT will become significant (usually
the expected output level for service application). The input level at which this
occurs is defined as the "capture level." The "overload point" of the EUT is the
value of the input signal that is 15 dB greater than the capture level.
14
15
16
17
18
(b)
Peak Limiting - An EUT with this type of limiting has virtually a constant throughtransmission gain over a range of input levels. As the input level is increased to
values beyond this range, the gain of the EUT begins to decrease. The
"overload point" of the EUT is defined as the input level at which the EUT's
through gain decreases by 0.4 dB from its nominal constant gain.
19
20
(4)
It is not necessary to test the EUT for compliance with input levels greater than
(+37) dBV.
21
22
23
24
25
26
27
(5)
The peak-to-average ratio of voiceband signals impacts the 3-second-average
power. Other signals such as voice and music have peak-to-average signal power
characteristics that vary over a large range; typically, they are greater than 13 dB.
Such signals therefore have 3-second-average power that is at least 13 dB below
their peak power. Hence, a peak limiting circuit that sets signal power limits to
correspond to the 3-second-average power specified in ANSI/TIA-968-A,
subclause 4.5.2.1.1, is quite restrictive.
28
29
30
31
32
33
34
35
36
37
38
It is quite restrictive for two reasons. First, the input/output characteristic was
determined using a sinusoidal input, whose peak-to-average ratio is significantly
smaller than typical signals. Furthermore, the average power of any signal applied
to the network would have to be several dB below the limiting level to avoid
distortion. Allowance for a reasonable peak-to-average ratio in setting the peak
limiting protective circuit's maximum output level is reasonable and not likely to
cause harm to the network. A reasonable value to use for the peak-to-average
ratio is 13 dB.
Consequently, a protection circuit which is categorized as a peak limiting device can
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2
3
4
5
6
have a maximum output level limited to a value 13 dB greater than that specified in
ANSI/TIA-968-A subclause 4.5.2.1. A protection circuit which is categorized as an AGC
device has its output level limited to the level specified in ANSI/TIA-968-A subclause
4.5.2.1.
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2
3
4
Note 1.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
5
Note 2.
Connect the voltmeter (VM2) across R1 of the loop simulator.
6
7
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to ANSI/TIA-968-A figures 1.1 to 1.12.
8
9
10
Figure 9.36-1. Voiceband Signal Power - Non-approved external signal sources
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2
3
4
5
6
7
8
9
10
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13
14
15
16
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18
19
20
21
22
10 TRANSVERSE BALANCE LIMITATIONS ANSI/TIA-968-A, 4.6
10.1 Transverse Balance, Analog ANSI/TIA-968-A, 4.6.2
10.1.1 Background
Crosstalk constitutes a "… degradation of service to persons other than the user of the
subject terminal equipment, his calling or called party" (47 CFR, 68.3 - Definition of
harm). Therefore crosstalk is minimized so that it cannot be detected by ordinary
terminal equipment or equipment in the telephone network. Telecommunications
terminals can be the cause of crosstalk into other circuits by converting differential
mode (metallic) signals to common mode (longitudinal) signals and transmitting them
toward the network. The interference can manifest itself as crosstalk in adjacent wire
pairs in the same cable sheath. Such interference can be minimized by adequately
controlling the symmetry of the terminal's impedances from each side of the line to
ground.
Transverse balance is a measure of the degree of that symmetry. It is a comparison of
the voltage level of a metallic signal which is generated, to the voltage level of any
resulting transverse signal; i.e., the ratio of metallic voltage, VM to transverse voltage,
VL. The result is expressed in dB as follows:
TransverseBalance 20logV M
23
24
25
26
27
V
L
Thus, the greater the VM to VL ratio, the better the transverse balance of the terminal
and the less likely it is to create interference.
28
29
30
31
32
33
34
Transverse Balance tests are applicable to the on-hook and off-hook states of one-port
2-wire analog terminal equipment including central office implemented telephones. The
Tip Ground state of a Central office implemented telephone should not be subjected to
this test because the momentary (200 to 1200 ms) unbalanced condition during the Tip
Ground state is not considered a network harm by network providers that use such
payphones.
35
36
37
38
10.1.2 Purpose
To determine the transverse balance of the EUT in its various operating modes.
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2
3
10.1.3 Equipment
(1)
Applicable loop simulator SEL#4 (see comment 6).
4
(2)
Frequency generator SEL#27.
5
(3)
Frequency selective voltmeter SEL#28 or spectrum analyzer SEL#34.
6
(4)
Transverse balance bridge SEL#30.
7
8
9
10
Note: Refer to subclause 5.5 for equipment details.
10.1.4 Equipment States Subject To Test
(1)
Power on:
11
(a)
On-hook (idle), when applicable.
12
(b)
Off-hook (quiet state).
13
(2)
Power off:
14
(a)
On-hook (idle), when applicable.
15
(b)
Off-hook (quiet state), if feasible with power off.
16
(3)
Power fail (if different than power off):
17
(a)
On-hook (idle), when applicable.
18
(b)
Off-hook (quiet state), if feasible with power fail.
19
20
21
22
23
24
25
26
27
28
29
Note: Terminal equipment may require special attention to ensure it is properly configured for this
test. For example, if the equipment would normally be connected to ac-power ground, coldwater-pipe ground, or if it has a metallic or partially metallic exposed surface, then these points
should be connected to the test ground plane. Similarly, if the EUT provides connections to
other equipment through which ground may be introduced to the equipment, then these points
should be connected to the test ground plane. Equipment that does not contain any of these
potential connections to ground should be placed on a conductive plate that is connected to the
test ground plane (see comment 2); this applies to both non-powered and ac-powered
equipment.
10.1.5 Procedure
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2
(1)
Connect a 600 ohm resistor to the test circuit of Figure 10.1-1.
3
(2)
Set the frequency generator to 200 Hz.
4
5
6
7
(3)
Adjust the frequency generator to an output level of 0.775 Vrms (0dBm) as
measured by the frequency selective voltmeter or spectrum analyzer set at 10 Hz
bandwidth and balanced input, across the 600 ohm calibration resistor (see
comment 8).
8
9
(4)
Connect the frequency selective voltmeter or spectrum analyzer across the 500 ohm
transverse termination resistor.
10
11
12
13
14
15
(5)
Adjust variable capacitors C3 and C4 until the minimum VL level across the 500 ohm
resistor is obtained. This represents the highest degree to which the bridge can be
balanced at the frequency being measured referenced to the level set in step (3).
Verify that the result of this balance calibration is at least 20 dB greater than the
balance requirement for the EUT at that frequency specified in ANSI/TIA-968-A
clause 4.6.2.
16
(6)
Substitute the EUT for the 600 ohm resistor. For multiport EUT, see comment 1.
17
18
19
(7)
Vary the loop current, for off-hook conditions, over the available range of loop
currents, observing the worst-case balance (maximum voltage across the 500 ohm
resistor).
20
21
(8)
Return the loop simulator to the condition resulting in the worst-case balance noted
in step (7).
22
23
(9)
Measure the voltage across the tip and ring of the EUT; this is the metallic reference
voltage (VM).
24
25
(10)
Measure the voltage across the 500 ohm resistor; this is the longitudinal voltage
(VL).
26
(11)
Calculate the balance using the following formula:
TransverseBalance 20logV M
27
28
29
30
31
V
L
Note: If the readings are, for example, taken in dBV, then the equation may be simplified to:
)
( dB ) of
( dBV )  V repeat
( dBV step
M EUT and
L
Vthe
(12) Reverse the tip and ringBalance
connections
(9) to step (11). The
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lesser of the two results is the transverse balance of the EUT at 200 Hz.
2
3
4
5
(13) Repeat step (3) through step (12) for at least each of the following frequencies: 500,
1000, 2000, 3000, and 4000 Hz, with the resolution bandwidth set for 10 Hz for the
500 Hz measurement and 30 Hz for all other frequencies (See Comment 3 and
Comment 8).
6
(14) Repeat step (2) through step (13) for all applicable equipment states.
7
8
9
10
10.1.6 Alternative Methods
11
12
13
10.1.7 Suggested Test Data
(1)
Frequencies tested.
14
(2)
Balance measured of the frequencies tested.
15
(3)
EUT and loop simulator condition for each measurement.
See Appendix C.
16
17
18
19
20
21
22
23
24
10.1.8 Comments
(1)
For multiport EUTs, input leads of ports not under test should be properly terminated
by connecting the terminating network shown in ANSI/TIA-968-A, Figure 4.9 to the
ports of the EUT not under test. Prior to connection, this terminating network should
be adjusted for its maximum balance by attaching it to the balance test set and
adjusting its potentiometer. Include the DC portion of the loop simulator during the
calibration process.
25
26
27
28
(2)
EUT that is not normally grounded should be set in its normal position directly on a
conductive plate. It is recommended that the overall area of the conductive plate be
at least 50% greater than that of the base of the EUT. This represents the closest
proximity to ground that is likely to be encountered by the EUT.
29
30
(3)
Interference from power frequency harmonics can be minimized by using test
frequencies midway between multiples of 60 Hz.
31
(4)
In some cases, the EUT may apply internally generated signals to the test set. Such
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2
3
signals should not be construed as part of the transverse balance test.
(5)
If a frequency selective voltmeter or spectrum analyzer are not available, transverse
balance measurements may be made if:
4
5
(a)
The environment is relatively free from electromagnetic interference in the
voiceband; and
6
(b)
The EUT generates very low in-band noise.
7
8
9
(c)
A bandpass filter with sufficient attenuation above and below the cutoff
frequencies and a high impedance voltmeter, each with a balanced input, may
be used.
10
11
(6)
To achieve an acceptable degree of calibration balance, the use of batteries in the
loop simulator circuit is recommended.
12
13
(7)
A DC current meter may be included as part of the loop simulator circuit in order to
monitor loop conditions.
14
15
16
(8)
For low frequencies, the narrower bandwidth (i.e. 10 Hz) is used in order to avoid
interference from power frequency harmonics. For the higher frequencies, the wider
bandwidth is used in order to enhance the measurement stability.
17
18
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2
T1
C1, C2
C3, C4
Osc
R1
RL
3
4
600 ohm: 600 ohm split audio transformer
8 µF, 400 V DC, matched to within 0.1%
100 to 500 pF adjustable trimmer capacitors
Audio oscillator with source resistance R1 less than or equal to 600 ohms
Selected such that ZOSC + R1 = 600 ohms
500 ohms
Note 1.
VM should not be measured at the same time as VL.
5
6
7
8
9
10
11
12
13
14
15
Note 2.
The test circuit should be balanced to 20 dB greater than the equipment standard for all
frequencies specified (using trimmer capacitors C3 and C4), with a 600 ohm resistor
substituted for the equipment under test. Exposed conductive surfaces on the exterior of
the equipment under test should be connected to the ground plane for this test. When the
Terminal Equipment makes provision for an external connection to ground, the Terminal
Equipment should be connected to ground. When the Terminal Equipment makes no
provision for an external ground, the Terminal Equipment should be placed on a ground
plane that is connected to ground and has overall dimensions at least 50% greater than
the corresponding dimensions of the Terminal Equipment. The Terminal Equipment
should be centrally located on the ground plane without any additional connection to
ground.
16
Note 3.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
17
18
19
Figure 10.1-1 Transverse Balance, Analog
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2
10.2
Transverse Balance, Digital ANSI/TIA-968-A, 4.6.3, 4.6.4
3
4
5
6
10.2.1 Background
See subclause 10.1.1.
7
8
9
10
10.2.2 Purpose
11
12
13
10.2.3 Equipment
(1)
Spectrum analyzer SEL#34
14
(2)
Tracking generator SEL#39.
To determine transverse balance of digital EUT.
15
Note: Refer to subclause 5.5 for equipment details.
16
17
18
19
20
21
22
23
24
25
26
27
28
10.2.4 Equipment States Subject To Test
29
30
31
32
10.2.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 10.2-1 with the appropriate calibration
test resistor (135 ohms or 100 ohms) in place.
33
(2)
Set the spectrum analyzer and tracking generator to the appropriate frequency
Active state with appropriate grounding applied.
Note: Terminal equipment may require special attention to ensure it is properly configured for this
test. For example, if the equipment would normally be connected to ac-power ground, coldwater-pipe ground, or if it has a metallic or partially metallic exposed surface, then these points
should be connected to the test ground plane. Similarly, if the EUT provides connections to
other equipment through which ground may be introduced to the equipment, then these points
should be connected to the test ground plane. Equipment that does not contain any of these
potential connections to ground should be placed on a conductive plate that is connected to the
test ground plane (see comment 1); this applies to both non-powered and ac-powered
equipment.
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ranges:
2
(a)
For 2.4 kilobit per second (kb/s) subrate EUT - 200 Hz to 2.4 kHz
3
(b)
For 3.2 kilobit per second (kb/s) subrate EUT - 200 Hz to 3.2 kHz
4
(c)
For 4.8 kilobit per second (kb/s) subrate EUT - 200 Hz to 4.8 kHz
5
(d)
For 6.4 kilobit per second (kb/s) subrate EUT - 200 Hz to 6.4 kHz
6
(e)
For 9.6 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 9.6 kHz
7
(f)
For 12.8 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 12.8 kHz
8
(g)
For 19.2 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 19.2 kHz
9
(h)
For 25.6 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 25.6 kHz
10
(i)
For 38.4 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 38.4 kHz
11
(j)
For 51.2 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 51.2 kHz
12
(k)
For 56.0 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 56.0 kHz
13
(l)
For 72.0 kb/s kilobit per second (kb/s) subrate EUT - 200 Hz to 72.0 kHz
14
(m)
For BRA EUT - 200 Hz to 192 kHz
15
(n)
For DS1 (1.544 Mb/s) EUT - 12 kHz to 1.544 MHz
16
(o)
For ADSL EUT – 13.6 kHz to 1.625 MHz (see comment 6)
17
(p)
For ADSL2+ EUT - 13.6 kHz to 2.425 MHz (see comment 6)
18
19
20
(3)
Adjust the tracking generator voltage to measure a VM of 0.367 Vrms across the
calibration test resistor of 135 ohms or 0.316 Vrms across the calibration test resistor
of 100 ohms as appropriate.
21
22
(4)
Connect the spectrum analyzer across the RL resistor (90 or 500 ohms as per
ANSI/TIA-968-A, Table 4.12).
23
24
25
26
27
(5)
Adjust capacitor C1 until a minimum voltage across the RL resistor is obtained. This
represents the highest degree to which the bridge can be balanced. The result of
this balance calibration should be at least 20 dB better than the requirement for the
applicable frequency band. If this degree of balance cannot be attained, further
attention should be given to component selection for the test circuit and its
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construction.
2
3
4
5
6
7
(6)
Reverse the polarity of the tip-and-ring pair under test. If the transverse voltage (VL)
changes by less than 1 dB, the calibration is acceptable. If the transverse voltage
changes by more than 1 dB, it indicates that the bridge needs further adjustment to
accurately measure the balance of the EUT. Repeat the calibration process until the
measurements differ by less than 1 dB while maintaining the balance noted in step
(5) above.
8
9
(7)
Replace the calibration resistor with one tip-and-ring pair of the EUT (see comment
4).
10
11
(8)
Measure the voltage across the tip and ring of the EUT; this is the metallic reference
voltage (VM).
12
(9)
Measure the voltage across the RL resistor; this is the longitudinal voltage (VL).
13
(10)
Calculate the balance using the following formula:
TransverseBalance 20logV M
V
14
15
16
17
18
Balance ( dB )  V
M
L
( dBV )  V L ( dBV )
Note: If the readings are, for example, taken in dBV, then the equation may be simplified to:
19
20
21
22
Reverse the tip and ring connections of the EUT and repeat step (8) through step (10).
The lesser of the two results is the transverse balance of this pair of the EUT.
(11) If applicable, connect the other tip and ring pair of the EUT to the balance test set
(see comment 4).
23
(12)
24
25
26
27
10.2.6 Alternative Methods
28
29
30
10.2.7 Suggested Test Data
Repeat step (8) through step (11) for this pair.
See Appendix C.
(1)
EUT tip and ring pair tested.
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(2)
Frequencies tested.
2
(3)
Balance measured for the pair.
3
(4)
Calibration balance measured.
4
5
6
7
8
9
10.2.8 Comments
(1)
EUT that is not normally grounded should be set in its normal position directly on a
conductive plate. It is recommended that the overall area of the conductive plate be
at least 50% greater than that of the base of the EUT. This represents the closest
proximity to ground that is likely to be encountered by the EUT.
10
11
(2)
Interference from power frequency harmonics can be minimized by using test
frequencies midway between multiples of 60 Hz.
12
13
(3)
In some cases, EUT may apply internally generated signals to the test set. Such
signals should not be construed as part of the transverse balance test.
14
15
(4)
Some digital equipment referenced in this subclause has a transmit pair and a
receive pair. Balance measurements should be performed on both pairs.
16
17
18
(5)
Test leads between the test fixture and the EUT will affect the calibration and EUT
balance measurements. Ensure that such cables are in place when making the
calibration balance adjustments.
19
20
21
22
(6)
Alternatively, a narrower frequency range may be used for the family of ADSL EUT
that is defined by the points at which the measured power spectral density is 20 dB
down from the maximum level associated with both the maximum rate upstream and
downstream signals.
23
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2
100/135 ohms:100/135 ohm wide-band transformer
(100 for 1.544 Mbps or ADSL devices and 135  for sub-rate or BRA
devices.)
Optimally a dual-stator air-variable RF capacitor that maintains a constant
20pF
capacitance between stators while providing a variable capacitance from either
Differential
stator to ground.
3 pF
Composition RF capacitor
RCAL
100/135 ohms (See Note 2)
90/500 ohms: A non-inductive precision resistor
RL
(chosen according to Table 4.12).
T1
3
4
5
Note 1.
The 3 pF capacitor may be placed on either line of the test set, as required, to obtain
proper balancing of the bridge.
6
7
Note 2.
Use an RCAL value of 100 ohms for 1.544 Mbps or ADSL devices and 135 ohms for subrate or BRA devices.
8
9
10
Note 3.
The effective output impedance of the tracking generator should match the appropriate
test impedance. See Note 2. The spectrum analyzer's input should be differentially
balanced to measure VM.
11
12
Note 4.
The impedance of the Tracking Generator should be chosen to match the Metallic
Termination (RM) according to ANSI/TIA-968-A, Table 4.12.
13
Note 5.
The transformer should be a wide band transformer with a 1:1 impedance ratio.
14
15
Figure 10.2-1 Transverse Balance, Digital
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2
3
11 ON HOOK IMPEDANCE LIMITATIONS ANSI/TIA-968-A, 4.7
11.1 DC Resistance ANSI/TIA-968-A, 4.7.2.1, 4.7.2.2
4
5
6
7
8
9
10
11
12
13
14
15
16
11.1.1 Background
17
18
11.1.2 Purpose
19
To measure the DC resistance of the EUT during its idle, or on-hook state.
20
21
22
11.1.3 Equipment
(1)
DC current meter SEL#19 or 20.
23
(2)
DC power supply SEL#21.
24
(3)
DC voltmeter SEL#22.
This requirement is necessary to avoid interference with telephone company
maintenance procedures. Telephone companies determine whether there is a line
insulation fault in their wire facilities by applying DC voltages to the individual wire pairs.
A fault condition is determined by the amount of current flow when DC voltages up to
200 V of either polarity are applied to a wire pair. For DC voltages up to 100 V, the
telephone company expects the total DC resistance of all terminal equipment bridged
across a wire pair to be greater than 5 megohms. (Any less resistance would interfere
with the line insulation tests and the ability to isolate a line problem from a terminal
equipment problem.) For DC voltages between 100 V and 200 V, the total DC
resistance of all connected terminal equipment is specified to be greater than
30 kilohms.
25
Note: Refer to subclause 5.5 for equipment details.
26
27
28
29
11.1.4 Equipment States Subject To Test
30
31
32
11.1.5 Procedure
The EUT should be in its idle or on-hook state. It may be necessary to test in both
powered and non-powered states if the EUT requires external power.
(1)
Connect the EUT to the test circuit
of Figure 11.1-1.
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(2)
Set the voltage to 1 V DC and allow the circuit to stabilise.
2
3
(3)
Slowly increase the voltage to 100 volts and observe the current as the voltage is
increased.
4
5
6
(4)
If the current is < 0.2 microamps over this range, measure and record the current at
1 volt. Use this value to calculate the minimum DC resistance for the 1 to 100 volts
range.
7
8
(5)
If the current increases suddenly at any point, record the voltage and current at
these points. Calculate the DC resistance at these points.
9
10
11
(6)
In addition to any points recorded in step (5), measure and record the current at
voltages of 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 volts. Use these values to
calculate the DC resistance at these voltages.
12
13
(7)
Slowly increase the voltage from 100 to 200 volts and observe the current as the
voltage is increased.
14
15
16
(8)
If the current is < 3.3 mA ( for measurements of current < 20 A, use meter #19
from the SEL) over this range, measure and record the current at 100 volts. Use
this value to calculate the minimum DC resistance for the 100 to 200 volts range.
17
18
(9)
If the current increases suddenly at any point, record the voltage and current at
these points.
19
20
(10)
In addition to any points recorded in step (7), measure and record the current at
voltages of 100, 150, and 200 volts.
21
(11)
Reverse the polarity of the test circuit and repeat steps (2) through (10).
22
(12)
Connect the EUT to the test circuit of figure 11.1-2.
23
24
(13)
Repeat steps (2) through step (10) with connections made to the tip and ground
leads of the EUT.
25
26
(14)
Repeat Steps (2) through (10) with connections made to the ring and ground leads
of the EUT.
27
28
29
30
11.1.6 Alternative Methods
Programmable DC resistance meters are available.
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2
3
11.1.7 Suggested Test Data
(1)
Statement that voltage was swept from 1 to 200 volts.
4
(2)
DC test voltages.
5
(3)
DC current readings.
6
(4)
DC resistances (calculated).
7
8
9
11.1.8 Comments
10
11
(1)
The internal resistances of all measuring equipment is to be taken into account.
(2)
Care should be exercised to prevent electromagnetic interference from affecting the
DC current measurements.
12
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2
3
4
Figure 11.1-1. DC Resistance, T-R
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2
3
4
5
Note: The 1 kilohm resistor is provided as a current limiter.
Figure 11.1-2. DC Resistance, T-GND & R-GND
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2
11.2 DC Current During Ringing, Loop Start and Ground Start ANSI/TIA-968-A,
4.7.2.3, 4.7.3.1
3
4
(1)
4.7.2.3 for loop start
5
(2)
4.7.3.1 for ground start
6
7
8
9
10
11
12
13
14
15
11.2.1 Background
16
17
18
19
11.2.2 Purpose
20
21
22
11.2.3 Equipment
(1)
AC Volt Meter SEL#3.
23
(2)
DC current meter SEL#19.
24
(3)
DC power supply SEL#21.
25
(4)
Frequency generator SEL#27.
26
(5)
Ringing amplifier SEL#33.
27
28
29
30
31
The limits placed on the DC current and AC impedance of terminal equipment during
ringing are to ensure that it does not cause the ring trip equipment at the CO to
disconnect the ringing generator prematurely (pre-trip). Ring trip equipment in COs
respond to either DC current or the combination of AC and DC current. When pre-trip
occurs, the calling customer does not receive audible ringback and perceives that the
call did not complete. Thus, the calling customer will make repeated attempts,
needlessly tie up the telephone network facilities, and possibly initiate unnecessary
maintenance efforts by the telephone company.
To measure the DC current that results from the nonlinear characteristics of the EUT
during ringing.
Note: Refer to subclause 5.5 for equipment details.
11.2.4 Equipment States Subject To Test
The EUT should be in its idle or on-hook state. If the EUT is an auto-answer device,
some means to disable this feature is necessary. It may be necessary to test in both
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powered and non-powered states if the EUT requires external power.
2
3
4
11.2.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 11.2-1.
5
6
(2)
Set the test equipment to supply the lowest frequency and voltage listed in Table
4.13 of subclause 4.7 for the ringing type being tested.
7
(3)
Record the DC current.
8
9
(4)
Increase the ringing voltage to the maximum for the chosen ringer type from Table
4.13 of subclause 4.7.
10
(5)
Record the DC current.
11
12
(6)
Repeat step (3) through step (5) for the other recommended frequencies (See
comment (1)).
13
14
(7)
Reverse the connections of the EUT to the test circuit and repeat step (2) through
step (6).
15
16
17
11.2.6 Alternative Methods
18
19
20
21
11.2.7 Suggested Test Data
22
23
24
25
11.2.8 Comments
(1)
For “A” type ringers, measure at 20 and 30 Hz. For "B" ringers, measure at 15.3, 20,
35, 50, and 68 Hz.
26
27
(2)
Take into account the internal characteristics (impedances) of all monitoring
equipment.
28
29
30
31
(3)
If the EUT derives operating power or power assist from the incoming ringing
signal, the EUT may be damaged by the continuously applied ringing as described in
this subclause. In such cases, special cadenced ringing tests maybe necessary to
obtain data. The ringing cadence is typically a repetitive cycle of two seconds on
None suggested.
The DC current at each of the AC voltage levels and frequencies.
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and four seconds off.
2
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2
3
4
5
6
Figure 11.2-1. DC Current During Ringing
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2
11.3 AC Impedance During Ringing, Loop Start and Ground Start (Metallic and
Longitudinal) ANSI/TIA-968-A, 4.7.2.4, 4.7.2.5, 4.7.3.2
3
4
(1)
4.7.2.4 and 4.7.2.5 for loop start
5
(2)
4.7.3.2 for ground start
6
7
8
9
10
11
12
13
14
15
11.3.1 Background
16
17
18
11.3.2 Purpose
19
20
21
11.3.3 Equipment
(1)
AC current meter SEL#1.
22
(2)
AC Volt Meter SEL#3.
23
(3)
DC power supply SEL#21.
24
(4)
Frequency generator SEL#27.
25
(5)
Ringing amplifier SEL#33.
26
27
The limits placed on the DC current and AC impedance of terminal equipment during
ringing are to ensure that it does not cause the ring trip equipment at the CO to
disconnect the ringing generator prematurely (pre-trip). Ring trip equipment in COs
respond to either DC current or the combination of AC and DC current. When pre-trip
occurs, the calling customer does not receive audible ringback and perceives that the
call did not complete. Thus, the calling customer will make repeated attempts,
needlessly tie up the telephone network facilities, and possibly initiate needless
maintenance efforts by the telephone company.
To measure the AC impedance of the EUT during ringing.
Note: Refer to subclause 5.5 for equipment details.
28
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2
3
4
5
11.3.4 Equipment States Subject To Test
6
7
8
11.3.5 Procedure
The EUT should be in its idle or on-hook state. If the EUT is an auto-answer device,
some means to disable this feature is necessary. It may be necessary to test in both
powered and non-powered states if the EUT requires external power.
(1)
Connect the EUT to the test circuit of Figure 11.3-1.
9
10
(2)
Set the frequency generator to the lowest frequency and voltage listed in Table
4.13 of subclause 4.7 for the ringing type being tested.
11
(3)
Record the current.
12
(4)
Calculate the AC impedance of the EUT.
13
14
(5)
Increase the ringing voltage to the maximum for the chosen ringer type from Table
4.13 of subclause 4.7.
15
(6)
Record the current.
16
(7)
Calculate the AC impedance of the EUT.
17
(8)
Repeat step (2) through step (7) at the other frequencies (see comment (1)).
18
19
(9)
Reverse the connections of the EUT to the test circuit and repeat step (2)
step (8).
20
(10)
Connect the EUT to the test circuit of Figure 11.3-2.
21
(11)
Repeat step (2) through step (9).
22
23
24
25
11.3.6 Alternative Methods
26
27
28
11.3.7 Suggested Test Data
None suggested.
(1)
The current at the various AC voltage levels and frequencies.
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(2)
Calculated AC impedances.
2
3
4
5
11.3.8 Comments
(1)
For “A” type ringers, measure at 20 and 30 Hz. For "B" ringers, measure at 15.3, 20,
35, 50, and 68 Hz.
6
7
(2)
Take into account the internal characteristics (impedances) of all monitoring
equipment.
8
9
10
11
(3)
If the EUT derives operating power or power assist from the incoming ring, the EUT
may be damaged by the continuously applied ringing as described in this subclause.
In such cases, special cadenced ringing tests maybe necessary to obtain data. The
ringing cadence is typically a repetitive cycle of two seconds on and four seconds off.
12
13
(4)
When testing series connected devices, remove all terminations from the nonnetwork side of the EUT as they could adversely affect the measurement.
14
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2
3
4
5
6
7
8
Figure 11.3-1. AC Impedance, T-R
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2
3
4
Figure 11.3-2. AC Impedance, T-GND & R-GND
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2
11.4 REN Calculation ANSI/TIA-968-A, 4.7.4, 4.7.5
3
4
5
6
7
8
9
10
11
12
13
11.4.1 Background
14
15
16
11.4.2 Purpose
17
18
19
11.4.3 Equipment
20
21
22
11.4.4 Equipment States Subject To Test
23
24
25
11.4.5 Procedure
26
27
28
11.4.6 Alternative Methods
29
30
31
11.4.7 Suggested Test Data
32
33
34
11.4.8 Comments
The on-hook requirements for AC impedance are specified in terms of the combined
effect of all terminal equipment connected to a particular network connection when a
ringing signal is applied by the CO. The ringer equivalence number (REN) provides a
method for allocating these requirements among terminal equipment devices attached
to a network connection. The REN also provides the customer with a simple procedure
for determining if the combined effect of all devices attached to the line is likely to cause
network operational faults. The customer determines this effect by adding the REN of
each device connected to the telephone line in question. The total REN should be less
than 5.0.
To calculate the REN for the EUT.
None.
Not applicable.
Refer to subclause 4.7.4 for computation of REN. Use data obtained in subclause 11.3.
None suggested.
A tabulation of the calculations performed.
The following is an example of how an REN (ac) of 0.7B is derived for "individual
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2
3
4
5
equipment intended for connection to loop start facilities":
(1)
AC data derived from subclause 11.3.5 is converted to REN numbers as described
in subclause 4.7.4 for tests at 16 Hz and 68 Hz, and subclause 4.7, Table 4.13,
ringing type B:
6
(2)
Assume at 150 V rms, 12.3 mA AC is measured at 68 Hz.
7
8
9
10
11
12
13
14
Ringer Impedance =
150
12.3  10 3
= 12.2 kohms
Assume 12.2 kohms to be the lowest ringer impedance for all ringing conditions.
(3)
Ringing type B allows a ringer impedance of 1600 ohms minimum on a single line
(refer to subclause 4.7), which is equivalent to 5 ringers each having a ringer load of
8000 ohms (5 X 1600 ohms). To calculate the ringer load (REN) for the EUT:
15
16
17
18
19
20
21
REN =
(4)
8000 ohms
8000 ohms

 0.66
Ringer Impedance 12.2  103 ohms
Thus, REN (ac) = 0.7B (rounded to nearest tenth) telephone ringer load. In this case,
seven such EUTs could be attached to a single loop start line. The "B" stipulates the
ringer type. The total REN is recorded on the label of the device in accordance with
the labelling requirement of the ACTA.
22
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2
11.5 OPS Ring Trip, PBX with DID ANSI/TIA-968-A, 4.7.6
3
4
5
6
7
8
9
10
11
11.5.1 Background
12
13
14
15
11.5.2 Purpose
16
17
18
11.5.3 Equipment
19
20
21
11.5.4 Equipment States Subject To Test
22
23
24
11.5.5 Procedure
(1)
Calculate the values for R and C according to subclause 4.7.6.
25
(2)
Connect the EUT to the test circuit of Figure 11.5-1.
26
(3)
Cause the EUT to generate ringing toward the termination.
27
(4)
Verify that ringing has not tripped.
28
29
30
11.5.6 Alternative Methods
31
32
11.5.7 Suggested Test Data
The purpose of this test is to ensure that a PBX will apply ringing towards an OPS in
order to complete a DID call. If the PBX's ringing generator trips prematurely, the
calling party will believe the call failed to complete and will repeat the attempt. This
failure to operate correctly results in unnecessary network maintenance procedures. In
this test, the ringing generator is terminated by an impedance that simulates the wire
pair impedance terminated by station set ringers with the stations in their on-hook
condition.
To verify that the EUT will not trip ringing when the maximum number of telephone
instruments as specified by the PBX manufacturer are connected to an OPS.
None.
The PBX equipment is to be tested while it is ringing an off-premise station.
None suggested.
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2
Test data should include the number of equivalent ringers (N) specified for the interface
under test, and confirmation that this termination did not trip ringing.
3
4
5
6
11.5.8 Comments
None.
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2
3
4
5
6
Note: The value of R and C are calculated in accordance with subclause 4.7.6.
Figure 11.5-1. OPS Ring Trip
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2
11.6 Transitioning to the Off-Hook State and Make-busy ANSI/TIA-968-A, 4.7.8
3
4
5
6
7
8
9
10
11
12
11.6.1 Background
13
14
15
16
17
18
11.6.2 Purpose
19
20
21
11.6.3 Equipment
22
23
24
11.6.4 Equipment States Subject To Test
25
26
27
28
29
11.6.5 Procedure
30
31
32
11.6.6 Alternate Methods
33
34
35
11.6.7 Suggested Test Data
This requirement prevents the intentional design of terminal equipment that will apply a
termination across the network connection for the purpose of making that equipment
and its network connection busy for incoming calls. The FCC does permit a station to
go off-hook, applying a temporary busy on that circuit, for the purpose of programming
an automatic dialer with the selected telephone numbers for future network dialing
purposes. The FCC also allows the terminal equipment to go off-hook, applying a
temporary busy on that circuit, for the purpose of detecting the presence of stutter dial
tone. The definition of the make-busy leads is presented in subclause 1.3.
To verify that the EUT does not go off-hook except for the purpose of initiating or
receiving a call, subject to the exceptions allowed in ANSI/TIA-968-A, subclause 4.7.8.1
and 4.7.8.2.
None.
Not applicable.
Evaluate the EUT to ensure that it does not go off-hook for purposes other than initiating
a call, receiving a call, manual programming of memory dialing numbers or automatic stutter
dial tone detection.
None.
Engineering analysis of EUT.
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2
3
4
5
6
7
8
9
10
11.6.8 Comments
This subclause describes the usage of the make-busy feature. It does not have any
specific tests that apply to the make-busy function. The MB and MB1 leads are
considered telephone connections and should comply with the requirements of
ANSI/TIA-968-A, subclauses 4.3 and 4.4 when isolated from tip and ring. When the
corresponding telephone line is of the loop start type, the tip and ring leads should
comply with all of ANSI/TIA-968-A when the MB and MB1 leads are bridged to the tip
and ring connections.
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2
3
4
5
6
7
11.7 Manual Programming of Repertory Numbers, ANSI/TIA-968-A, 4.7.8.1
11.7.1 Background
This requirement is applicable to product capable of providing repertory (memory) or
automatic dialing for network addressing. The user is allowed to place the product in the
off-hook state for programming of repertory numbers or automatic dialing.
8
9
10
11
11.7.2 Purpose
12
13
14
15
16
11.7.3 Equipment
17
18
19
20
11.7.4 Equipment States Subject to Test
21
22
23
24
25
26
27
11.7.5 Procedure
28
29
30
11.7.6 Alternative Methods
31
32
33
34
11.7.7 Suggested Test Data
To verify that the equipment can program memory dialing in the off-hook state without
providing actual network address signaling (e.g. DTMF or pulse dialing).
Oscilloscope SEL #23
Note: refer to subclause 5.5 for equipment details.
Test any off-hook state.
(1)
(2)
(3)
Examine the customer instructions for the EUT and determine if it provides the
capability to program internal memory for repertory or automatic dialing.
Set the EUT to the appropriate dial method, and connect to the test circuit 11.7-1.
Place the EUT off-hook and perform the recommended programming sequence.
None suggested
State if network address signals or pulses are generated on tip and ring during the offhook programming sequence.
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2
3
4
5
6
7
8
9
10
11
12
13
14
11.7.8 Comments
This requirement is applicable to all EUT that provides memory or automatic dialing.
Note 1.
Select the appropriate loop simulator for the interface of the EUT. Refer to the
figures of clause 1 of ANSI/TIA-968-A.
Note 2.
The oscilloscope should provide a balanced input.
Figure 11.7-1. Manual Programming of Repertory Dialing Numbers
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2
3
4
5
6
7
8
9
11.8 Automatic Stuttered Dial Tone Detection ANSI/TIA-968-A, 4.7.8.2
11.8.1 Background
It is possible for some equipment to use automatic off-hook checks of the line to detect
a stutter dial tone, which is used to provide an audible signal to the equipment user in
support of certain network features. Unlimited or excessively long duration automatic
off-hook checks for the purpose of stutter dial tone detection is a misuse of network
facilities and is considered network harm.
10
11
12
13
11.8.2 Purpose
14
15
16
11.8.3 Equipment
(1)
Applicable loop simulator SEL#4.
17
(2)
Storage oscilloscope SEL#23.
18
(3)
Frequency generator SEL#27.
19
(4)
Ringing amplifier SEL#33.
20
21
22
11.8.4 Equipment States Subject To Test
23
24
25
26
27
28
11.8.5 Procedure
(1)
Consult the EUT manual to determine if the equipment performs automatic stutter
dial tone detection. Equipment that does not support this function is not subject to
this test. Verify that equipment supporting this function passes the conditions of
steps (2) through (6).
29
(2)
Connect the EUT to the test circuit of Figure 11.8-1.
30
31
32
(3)
Simulate the completion of a calling event by means of the host or ancillary
telephone set. Monitor and record the number of stuttered dial tone checks that
occur and when they occur.
To verify that the characteristics of the EUT automatic off-hook checks for stutter dial
tone detection meet the requirements of ANSI/TIA-968A.
Test when the EUT makes a stutter dial tone check.
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2
3
4
5
(4)
Simulate an unanswered incoming calling event. Monitor and record the number of
stuttered dial tone checks that occur and when they occur. If the device has a visual
message indicator, set the EUT so that the indicator is lit. Simulate an unanswered
incoming calling event. Monitor and record the number of stuttered dial tone checks
that occur and when they occur.
6
7
8
9
(5)
Cause the EUT to perform a stuttered dial tone check as in step (3) above. When
the device goes off-hook, apply dial tone within 3 seconds. Measure the amount of
time from the initial application of the dial tone to when the device goes back onhook.
10
11
12
(6)
Cause the EUT to perform a stuttered dial tone check as in step (3) above. When
the device goes off hook, do not apply dial tone within the first 3 seconds. Monitor
and record when the EUT goes back on hook.
13
14
15
11.8.6 Alternate Methods
16
17
18
11.8.7 Suggested Test Data
(1)
Number of stuttered dial tone checks after the completion of a calling event.
19
20
(2)
Time interval from the completion of a calling event to the completion of the stuttered
dial tone check.
21
22
(3)
Number of stuttered dial tone checks after the completion of an unanswered
incoming calling event.
23
24
(4)
Number of stuttered dial tone checks after the completion of an unanswered
incoming calling event attempted while the visual message indicator is lit.
25
26
(5)
Duration of the stuttered dial tone check after dial tone application when dial tone is
applied within three seconds.
27
28
(6)
Duration of the stuttered dial tone check with no dial tone applied within three
seconds.
29
30
(7)
Provide an attestation that states that the design of the EUT complies with the
requirement of subclause 4.7.8.2 a), f) and g) of ANSI/TIA-968-A.
31
32
11.8.8 Comments
None.
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2
(1)
The suggested level for application of dial tone is -13 dBm. This corresponds with
specified network levels.
3
(2)
Dial tone is specified in T1.401.
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
EUT
LOOP SIMULATOR
(Note 1)
RING
AMPLIFIER
FREQUENCY
GENERATOR
OSCILLOSCOPE
(Note 2)
Note 1.
Select the appropriate loop simulator for the interface of the EUT. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
Note 2.
The oscilloscope should provide a balanced input.
Figure 11.8-1. Manual Programming of Repertory Dialing Numbers
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2
3
4
5
12 BILLING PROTECTION ANSI/TIA-968-A, 4.8
12.1 Call Duration for Data Equipment, Protective Circuitry ANSI/TIA-968-A,
4.8.1.1
6
7
8
9
10
11
12
13
12.1.1 Background
14
15
16
17
12.1.2 Purpose
18
19
20
12.1.3 Equipment
(1)
Applicable loop simulator SEL#4.
21
(2)
Bandpass filter SEL#12.
22
(3)
Digital sampling storage oscilloscope SEL#24.
23
(4)
Frequency generator SEL#27.
24
(5)
Ringing amplifier SEL#33.
25
26
This requirement applies to protective circuitry for data equipment that has access to
the public switched network. The two-second delay before transmission of the data
signal, after the off-hook condition is presented to the telephone network in response to
an incoming call, is to allow billing equipment to be connected and prepared for proper
billing. The specified -55 dBm limit for transmission is considered to be equivalent to no
transmission and applies in both the transmit and receive conditions.
To verify that no data is delivered to or received from the network for the first two
seconds after answering an incoming call through a protective circuit.
Note: Refer to subclause 5.5 for equipment details.
27
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2
3
12.1.4 Equipment States Subject to Test
4
5
6
12.1.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.1-1.
7
(2)
Set the frequency generator for 1000 Hz and 0 dBm.
8
9
(3)
Set the oscilloscope to trigger on transition from the on-hook to the off-hook state of
the EUT.
10
(4)
Apply the ringing signal to the EUT.
11
12
(5)
Record the signal level that is transmitted to the network after the EUT goes offhook. Check for compliance during the first 2 seconds after going off-hook.
13
(6)
Connect the EUT to the test circuit of Figure 12.1-2.
14
(7)
Set the frequency generator to 1000 Hz and -55 dBm.
15
16
17
(8)
Place the EUT in the off-hook state. Measure the signal power that would be
delivered to the data equipment from the network through the EUT in response to a
received signal power of -55 dBm. Return the EUT to its on-hook state.
18
(9)
Increase the input signal 0 dBm.
19
20
(10)
Set the oscilloscope to trigger on transition from the on-hook to the off-hook state of
the EUT.
21
(11)
Apply the ringing signal to the EUT.
22
23
(12)
Measure the signal power that would be received by the data equipment from the
Network through the EUT (see comment (3)).
24
25
26
12.1.6 Alternate Methods
27
28
29
12.1.7 Suggested Test Data
Answering an incoming call (on-hook to off-hook transition).
None suggested.
(1)
Signal power in dBm for at least the first two seconds after transition to the off-hook
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state in both directions of transmission.
2
(2)
Verification of data delay.
3
4
5
12.1.8 Comments
(1)
Actual data signals may be used in place of the signal generator.
6
(2)
Test frequencies other than 1000 Hz may be used.
7
8
(3)
The signal level measured in Step (12) should be no greater than the signal level in
Step (8).
9
10
11
12
13
14
15
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
16
17
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of clause
1 of ANSI/TIA-968-A.
18
19
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
20
21
22
23
Figure 12.1-1. Call Duration, PC, Transmit
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2
3
4
5
6
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
7
8
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of clause
1 of ANSI/TIA-968-A.
9
10
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
11
12
13
14
Figure 12.1-2. Call Duration, PC, Receive
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2
12.2 Call Duration for Data Applications, Terminal Equipment ANSI/TIA-968-A,
4.8.1.2
3
4
5
6
7
8
12.2.1 Background
This requirement applies to data equipment that accesses the public switched network.
The two-second delay before transmission of the data signal after the off-hook condition
is presented to the telephone network in response to an incoming call is to allow billing
equipment to be connected and prepared for proper billing.
9
10
11
12
12.2.2 Purpose
13
14
15
12.2.3 Equipment
(1)
Applicable loop simulator SEL#4.
16
(2)
Digital sampling storage oscilloscope SEL#24.
17
(3)
Data generator SEL#18.
18
(4)
Ringing amplifier SEL#33.
To verify that the data equipment does not transmit or receive data for the first two
seconds after answering an incoming call.
19
20
Note: Refer to subclause 5.5 for equipment details.
21
22
23
24
25
12.2.4 Equipment States Subject to Test
26
27
28
12.2.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.2-1.
29
30
(2)
Set the oscilloscope to trigger on the transition from the on-hook to the off-hook
state.
Answering an incoming call, transmitting and receiving data (on-hook to off -hook
transition).
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(3)
Apply the ringing signal to the EUT.
2
3
4
5
(4)
Monitor the signal transmitted by the EUT for at least two seconds after the on-hook
to off-hook transition under normal operating conditions. Verify that data
transmission is delayed for the required time. If a signal is observed in less than the
required time, verify that it is one of the allowed signals.
6
(5)
Connect the EUT to the test circuit of Figure 12.2-2.
7
(6)
Set the EUT to receive data.
8
9
(7)
Set the oscilloscope to trigger on the transition from the on-hook to the off-hook state
of the EUT.
10
(8)
Apply the ringing signal to the EUT.
11
12
(9)
Monitor the EUT to verify that it does not respond to the incoming data for the time
specified in the test requirement after going off-hook (see comment).
13
14
12.2.6 Alternative Methods
15
16
None suggested.
17
18
12.2.7 Suggested Test Data
19
20
Verification of the data delay.
21
22
23
24
25
26
12.2.8 Comments
It may not be possible to determine whether or not data has been received.
Engineering analysis and attestation by the applicant may be necessary in these cases.
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2
3
4
5
6
7
8
9
10
Note 1.
The companion terminal equipment should provide the termination for this test; therefore,
R1 of the loop simulator may be removed. The loop simulator provides loop current for
both the EUT and the companion equipment.
Note 2.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
Figure 12.2-1. Call Duration, EUT, Transmit
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2
3
4
5
6
7
8
9
10
11
Note 1.
The companion terminal equipment should provide the termination for this test; therefore,
R1 of the loop simulator may be removed. The loop simulator provides loop current for
both the EUT and the companion equipment.
Note 2.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
Figure 12.2-2. Call Duration, EUT, Receive
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12.3 On-hook Signal Power, Analog ANSI/TIA-968-A, 4.8.2
2
3
4
5
6
12.3.1 Background
7
8
9
12.3.2 Purpose
The -55 dBm or less transmission level specified for an on-hook condition is considered
to be equivalent to no transmission. This requirement is intended to avoid the
transmission of information without activating the billing equipment.
To verify that no signal is applied to the network when the EUT is in the on-hook state.
10
11
12
12.3.3 Equipment
(1)
Applicable loop simulator SEL#4.
13
(2)
Bandpass filter SEL#5.
14
(3)
True rms AC Voltmeter SEL#40.
15
Note: Refer to subclause 5.5 for equipment details.
16
17
18
12.3.4 Equipment States Subject to Test
19
12.3.5 Procedure
20
21
22
23
12.3.5.1
(1)
Connect the EUT to the test circuit of Figure 12.3-1 using the 200 Hz to 4000 Hz
bandpass filter and voltmeter.
24
(2)
Place the EUT in the on-hook state.
25
(3)
Measure and record the maximum signal power level in dBm.
26
(4)
Verify that the signal level is less than the limit.
27
28
12.3.5.2
On-hook state.
For Terminal Equipment:
For Protective Circuits:
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(1)
Connect the EUT to the test circuit of Figure 12.3-2.
2
(2)
Place the EUT in its on-hook state.
3
4
(3)
Adjust the input signal to the EUT to 1000 Hz at a level at least 10 dB above the
overload point.
5
(4)
Measure and record the output signal power level in dBm.
6
12.3.6 Alternate Methods
7
8
9
10
12.3.6.1
For Terminal Equipment:
(1)
Connect the EUT to the test circuit of Figure 12.3-1 and replace the bandpass filter
and true rms AC voltmeter with a signal analyzer (SEL#56).
11
(2)
Set the signal analyzer to measure the following:
12
(j)
Signal level in dBm, 600 ohms.
13
(k)
Averaging over 3 second.
14
(l)
Band pass power in the frequency range of 200 Hz to 4000 Hz band.
15
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
16
17
18
(4)
Place the EUT in the on-hook state and measure and record the maximum signal
power level.
19
20
21
12.3.7 Suggested Test Data
(1)
For terminal equipment, on-hook signal power level in dBm.
22
(2)
For protective circuitry, record the input level in dBV and the output level in dBm.
23
24
25
26
27
28
12.3.8 Comments
On-hook includes states where signal sources in the EUT are active but which are
intended to be isolated from the network.
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2
3
4
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
5
6
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
7
8
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
9
10
Figure 12.3-1. On-hook Signal Power, TE
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2
3
4
Note 1.
Select the appropriate loop simulator for the interface of the EUT.
5
6
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
7
8
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
9
Note 4.
The frequency generator is only required for testing protective circuitry.
10
11
12
13
14
15
Figure 12.3-2. On-hook Signal Power, PC
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12.4 Off-Hook Loop Current ANSI/TIA-968-A, 4.8.3
2
3
4
5
6
12.4.1 Background
The loop current restriction for the first five seconds, and subsequent requirements, are
necessary to ensure connection and operation of the billing equipment of the telephone
company.
7
8
9
10
12.4.2 Purpose
11
12
13
12.4.3 Equipment
(1)
Applicable loop simulator SEL#4.
14
(2)
DC current meter SEL#19.
15
(3)
Digital sampling storage oscilloscope SEL#24.
16
(4)
Frequency generator SEL#27 (if required).
17
(5)
Ringing amplifier SEL#33 (if required).
18
19
20
21
22
23
24
25
To measure the off-hook DC current drawn by the EUT from the loop simulator in the
first five seconds after the on-hook to off-hook transition.
Note: Refer to subclause 5.5 for equipment details.
12.4.4 Equipment States Subject to Test
The first five seconds after the EUT transfers from the on-hook to the off-hook state in
response to an incoming call.
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2
12.4.5 Procedure
3
Note: Either of the two following methods can be used:
4
5
6
12.4.5.1
Method A: Comparison With Current through a 200 ohm Resistor
(1)
Connect the EUT to the test circuit of Figure 12.4-1.
7
(2)
Set the DC voltage of the loop simulator to 42.5 V DC.
8
(3)
Set switch S1 to position "A”.
9
10
(4)
Adjust resistor R2 of the loop simulator to 1740 ohms and record the loop current
through the 200 ohm resistor.
11
(5)
Set switch S1 to position "B”.
12
(6)
Cause the EUT to go off-hook.
13
14
(7)
Monitor the DC current for the first five seconds after transferring from the on-hook to
the off-hook state. Record the minimum current level during the first five seconds.
15
16
(8)
If the DC current drawn by the EUT is equal to or greater than the DC current
measured in step (4), then the requirement is met.
17
18
19
20
12.4.5.2
Method B: Percent Change in DC Current
(1)
Connect the EUT to the test circuit of Figure 12.4-2.
21
22
(2)
Place the EUT in its off-hook condition and adjust resistance R2 to its maximum
value and adjust the source voltage to its minimum value (1740 ohms, 42.5 V DC).
23
(3)
Place the EUT in its on-hook state.
24
(4)
Set the oscilloscope to trigger on the transition from on-hook to off-hook of the EUT.
25
(5)
Cause the EUT to go off-hook.
26
27
(6)
Monitor voltage across the 10 ohm resistor for the first five seconds after transferring
the EUT from the on-hook state to the off-hook state. Record the maximum and
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minimum voltage levels.
2
3
(7)
The percent change in current will be equal to the percent change in voltage of the
minimum voltage level relative to the maximum voltage during the first five seconds.
4
5
(8)
Set R2 set to its minimum value and adjust the source voltage to its maximum value
(400 ohms, 56.5 V DC).
6
(9)
Repeat Step (3) through Step (7).
7
8
(10)
Set R2 to a value that produces a mid-range current and adjust the source voltage
to its maximum value (1200 ohms, 52.5 V).
9
(11)
Repeat Step (3) through Step (7).
10
11
12
12.4.6 Alternative Methods
13
14
12.4.7 Suggested Test Data
15
16
17
12.4.7.1
(1)
Loop current measured with 200-ohm resistor (mA DC).
18
(2)
Loop current measured with EUT (mA DC).
19
(3)
Comparison of loop currents.
20
(4)
Resistor R2 range.
21
22
23
12.4.7.2
(1)
Maximum and minimum off-hook DC voltage during the first five seconds.
24
(2)
Percent change during first five seconds.
25
(3)
Resistor R2 range.
26
27
12.4.8 Comments
None suggested.
Method A: Comparison with 200 ohm Resistor
Method B: Percent Change in Loop Current
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(1)
Chart recorder can be used in place of oscilloscope.
2
3
(2)
A DC current probe may be used with the oscilloscope to monitor current instead of
voltage.
4
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2
3
4
5
6
7
8
9
10
Note 1.
Only the DC portion of the loop simulator circuit should be connected for this test.
Note 2.
Loop current is measured with a current meter in series with R2 of the loop simulator
Refer to the figures of clause 1 of ANSI/TIA-968-A.
Figure 12.4-1. Loop Current, 200 ohm Method
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2
3
4
Note 1.
Only the DC portion of the loop simulator circuit should be connected for this test.
5
Note 2.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
6
7
8
Figure 12.4-2. Loop Current, 25% Method
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2
12.5 Signaling Interference, Analog ANSI/TIA-968-A, 4.8.4.1
3
4
5
6
7
8
9
10
11
12.5.1 Background
12
13
14
15
16
12.5.2 Purpose
17
18
19
12.5.3 Equipment
(1)
Applicable loop simulator SEL#4.
20
(2)
Bandpass filter SEL#6.
21
(3)
Bandpass filter SEL#7.
22
(4)
Frequency generator SEL#27 (if required).
23
(5)
Ringing amplifier SEL#33 (if required).
24
(6)
True rms AC voltmeter SEL#40.
25
26
This requirement is necessary so that the equipment does not interfere with the 2600
Hz billing signal. The signaling interference requirements only apply to the first two
seconds after the called station goes off-hook in response to an incoming alerting
signal. The 2600 Hz limitation is required to ensure adequate time for the connection
and operation of billing equipment. Failure to comply with this requirement after the first
two seconds will result in operational problems and is self correcting (see also FCC
Public Notice 9160, Ref A10 in subclause 3).
To verify that the signal power generated in the 2450 Hz to 2750 Hz frequency band is
no greater than that generated in the 800 Hz to 2450 Hz frequency band for the first two
seconds.
Note: Refer to subclause 5.5 for equipment details.
27
28
29
30
12.5.4 Equipment States Subject to Test
31
12.5.5 Procedure
Test the first two seconds after the EUT goes off-hook in response to receiving an
alerting signal.
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2
(1)
Connect the EUT to the test circuit of Figure 12.5-1.
3
(2)
Select the bandpass filter for the 800 Hz to 2450 Hz band.
4
(3)
Initiate a call into the EUT.
5
6
(4)
Measure the maximum signal power in dBm after the EUT goes off-hook for the
first two seconds.
7
(5)
Return the EUT to its on-hook state.
8
(6)
Select the bandpass filter for the 2450 Hz to 2750 Hz band.
9
(7)
Initiate a call into the EUT.
10
11
(8)
Measure the maximum signal power in dBm after the EUT goes off-hook for the
first two seconds.
12
13
(9)
Compare the energy in the 2450 Hz to 2750 Hz band to the energy in the 800 Hz to
2450 Hz band.
14
(10)
Repeat Step (2) through Step (9) for all other call answering modes, if applicable.
15
16
17
18
12.5.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 12.5-1 and replace the bandpass filter
and true rms AC voltmeter with a signal analyzer (SEL#56).
19
(2)
Set the signal analyzer to measure the following:
20
(m) Signal level in dBm, 600 ohms.
21
(n)
Averaging over 2 seconds.
22
(o)
Band pass power in the frequency range of 800 Hz to 2450 Hz band.
23
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
24
(3)
Initiate a call into the EUT.
25
26
(4)
Measure the maximum signal power in dBm after the EUT goes off-hook for the first
two seconds.
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(5)
Return the EUT to its on-hook state.
2
3
(6)
Set the band pass power of the Signal Analyzer to the frequency range of 2450 Hz to
2750 Hz band.
4
(7)
Initiate a call into the EUT.
5
6
(8)
Measure the maximum signal power in dBm after the EUT goes off-hook for the first
two seconds.
7
8
(9)
Compare the energy in the 2450 Hz to 2750 Hz band to the energy in the 800 Hz to
2450 Hz band.
9
(10) Repeat Step (3) through Step (9) for all other call answering modes, if applicable.
10
11
12
13
12.5.7 Suggested Test Data
(1)
800 Hz to 2450 Hz band energy.
14
(2)
2450 Hz to 2750 Hz band energy.
15
(3)
Signal power levels in dBm.
16
17
18
19
12.5.8 Comments
(1)
Two bandpass filters and two voltmeters may be used so that measurements in the
two bands can be taken simultaneously.
20
21
(2)
A voltmeter or signal analyzer that can be triggered by the on-hook to off-hook
transition is helpful.
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23
(3)
Refer to subclause 4.8.1 of ANSI/TIA-968-A for conditions where data equipment is
exempt from this requirement.
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Note 1.
Select the appropriate loop simulator for the interface of the EUT.
6
7
Note 2.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
8
9
Note 3.
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of clause 1 of ANSI/TIA-968-A.
10
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Figure 12.5-1. Signaling Interference
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12.6 Signaling Interference, Digital ANSI/TIA-968-A, 4.8.4.2
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12.6.1 Background
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12.6.2 Purpose
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12.6.3 Equipment
(1)
Bandpass filter SEL#6.
19
(2)
Bandpass filter SEL#7.
20
(3)
Companion terminal equipment SEL#15.
21
(4)
Multiplexer/demultiplexer SEL#32.
22
(5)
True rms AC voltmeter SEL#40 (qty 2).
23
(6)
Zero-level encoder/decoder SEL#46.
24
25
26
27
28
29
30
31
Transmission of analog signals in the band about 2600 Hz may interfere with the proper
operation of network billing equipment unless an equal or greater amount of energy is
present in the guard band. Therefore, the 2600 Hz energy in encoded analog signals
that are decoded and transmitted on the analog network needs to be controlled.
The requirements of this subclause apply to the called station during the first two
seconds of connection.
To verify that the signal power contained in the encoded analog signal in the signaling
band (2450 Hz to 2750 Hz) is less than or equal to the power contained in the guard
band (800 Hz to 2450 Hz).
Note: Refer to subclause 5.5 for equipment details.
12.6.4 Equipment States Subject to Test
The EUT is to be active and transmitting the encoded analog signal. The test is to be
performed on internally generated signals other than DTMF signals that the EUT can
transmit in the first two seconds after the EUT goes off-hook in response to receiving an
alerting signal.
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12.6.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.6-1. As shown, two types of signals
may be transmitted:
5
6
(a)
Internally generated signals that are generated directly in digital form but
which are intended for eventual conversion to analog form;
7
8
(b)
Internally generated analog signals that are converted to digital format for
eventual reconversion to analog form.
9
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11
(2)
For signals of type (a) or type (b) as described above, cause the equipment to
generate each of the possible signals in the first two seconds after the EUT goes offhook.
12
(3)
Read the signal energy in the 800 Hz to 2450 Hz band.
13
(4)
Read the signal energy in the 2450 Hz to 2750 Hz band.
14
(5)
Repeat Step (3) and Step (4) for all other call answering modes, if applicable..
15
16
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12.6.6 Alternative Methods
19
(1) Connect the EUT to the test circuit of Figure 12.6-1 and replace the bandpass filters
and true rms AC voltmeters with a signal analyzer (SEL#56).
(2) Set the signal analyzer to measure the following:
20
a. Signal level in dBm, 600 ohms.
21
b. Averaging over 2 seconds.
22
c. Band pass power in the frequency range of 800 Hz to 2450 Hz band.
23
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
24
25
26
(3) For signals of type (a) or type (b) as described above, cause the equipment to
generate each of the possible signals in the first two seconds after the EUT goes offhook.
27
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(4) Measure the maximum signal power in dBm after the EUT goes off-hook for the
first two seconds.
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(5) Read the signal energy in the 800 Hz to 2450 Hz band.
2
3
(6) Set the band pass power of the Signal Analyzer to the frequency range of 2450 Hz
to 2750 Hz band.
4
(7) Read the signal energy in the 2450 Hz to 2750 Hz band.
5
(8) Repeat Step (3) through Step (7) for all other call answering modes, if applicable.
6
7
8
9
12.6.7 Suggested Test Data
(1)
The signal which was measured.
10
(2)
The signal power contained in the band from 800 Hz to 2450 Hz .
11
(3)
The signal power contained in the band from 2450 Hz to 2750 Hz .
12
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12.6.8 Comments
(1)
A 600 ohm termination should be applied at the input of the filter, and the voltmeter
should be unterminated.
16
(2)
Simultaneous measurement of the signal power contained in each band is preferred.
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Figure 12.6-1. 1.544 Mb/s, Signaling Interference
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12.7 On-Hook Signal Power, Subrate and 1.544 Mb/s ANSI/TIA-968-A, 4.8.5
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12.7.1 Background
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12.7.2 Purpose
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12.7.3 Equipment
(1)
Companion terminal equipment SEL#15.
21
(2)
Multiplexer/demultiplexer SEL#32.
22
(3)
True rms AC voltmeter SEL#40.
23
(4)
Zero-level encoder/decoder SEL#46.
These requirements define the on-hook conditions in terms of encoded analog signal
power. The -55 dBm limit ensures that no useful information is exchanged when the
associated analog equipment displays an on-hook condition to the network.
Reverse battery is used on one-way incoming trunks from a telephone company to a
PBX (known as direct inward dialing trunks). In this case, the digital facility would have
to be part of such a trunk connection.
To verify the equivalent analog level content in the on-hook state for Subrate, 1.544
Mb/s terminal equipment, 1.544 Mb/s protective circuitry and 1.544 Mb/s reverse
battery.
24
25
Note: Refer to subclause 5.5 for equipment details.
26
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12.7.4 Equipment States Subject to Test
30
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12.7.5 Procedure
The EUT is to be in the on-hook state and transmitting the on-hook digital signal.
(1)
Connect the EUT to the test circuit of Figure 12.7-1.
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(2)
Cause the digital equipment to transmit the on-hook signal.
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3
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(3)
Measure the signal power as derived at the output of the zero-level decoder or
companion terminal equipment.
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6
7
8
12.7.6 Alternative Methods
(1)
Connect the EUT to the test circuit of Figure 12.7-1 and replace the bandpass filter
and true rms AC voltmeter with a signal analyzer (SEL#56).
9
(2)
Set the signal analyzer to measure the following:
10
(p)
Signal level in dBm, 600 ohms.
11
(q)
Averaging over 3 seconds.
12
(r)
Band pass power in the frequency range of 200 Hz to 4000 Hz band.
13
Note: Signal Analyzer should provide a balanced input, or an isolation transformer may be used.
14
15
16
(3)
Place the EUT in the on-hook state and measure and record the maximum signal
power level.
17
18
19
12.7.7 1.544 Mb/s Protective Circuits
(5)
Connect the EUT to the test circuit of Figure 12.7-1
20
(6)
Place the EUT in its on-hook state.
21
22
(7)
Provided an 1000 Hz input signal to the EUT at a level at least 10 dB above the
overload point.
23
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(4)
Measure and record the output signal power level in dBm.
25
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12.7.8 Suggested Test Data
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12.7.9 Comments
The measured on-hook signal level in dBm with respect to 600 ohms.
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4
On-hook includes states where signal sources in the EUT are active but which are
intended to be isolated from the network.
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9
Figure 12.7-1. Subrate and 1.544 Mb/s, On-hook Level
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12.8 Signaling Duration, 1.544 Mb/s ANSI/TIA-968-A, 4.8.6
12.8.1 Background
This requirement ensures that the off-hook signal to the network persists for at least five
seconds, unless the terminal equipment actually returns to the on-hook state. This is
the maximum time required to set up a call in a CO (including high speed automatic
dialing by terminal equipment) and properly record the initial billing information (calling
and called numbers).
10
11
12
12.8.2 Purpose
13
14
15
12.8.3 Equipment
(1)
Companion terminal equipment SEL#15.
16
(2)
Multiplexer/demultiplexer SEL#32.
17
(3)
Zero-level encoder/decoder SEL#46.
To verify the minimum active signaling duration.
18
19
Note: Refer to subclause 5.5 for equipment details.
20
21
22
12.8.4 Equipment States Subject to Test
23
24
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12.8.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.8-1.
26
(2)
Apply incoming alerting signaling to the input of the EUT.
27
28
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(3)
Cause the EUT to respond to the incoming signaling by whatever means are normal
for the equipment; for example, by answering the call at the system console or by
seizure of the associated analog channel.
30
(4)
Immediately remove the alerting signal.
Place the device in the off-hook state in response to the alerting signal.
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(5)
Monitor the outgoing signaling bits from the digital equipment or the state of the
associated companion terminal equipment for a minimum of 5 seconds to assure
that the EUT continues to transmit the signaling bit sequence representing the offhook state for 5 seconds, unless the EUT is returned to the on-hook state during the
5-second interval.
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8
12.8.6 Alternative Methods
9
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12.8.7 Suggested Test Data
12
13
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12.8.8 Comments
None suggested.
State whether the digital equipment complies with this requirement.
This test applies only to channelized 1.544 megabits per second (Mb/s) digital
equipment.
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Figure 12.8-1. 1.544 megabits per second (Mb/s), Signaling Duration
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12.9 Operating Requirements for DID ANSI/TIA-968-A, 4.8.7
12.9.1 Background
This requirement ensures that the off-hook signal to the network interface commences
within 0.5 seconds of the called station answering the call. The requirement is
necessary to initiate billing.
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10
12.9.2 Purpose
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12
13
12.9.3 Equipment
(1)
Companion Terminal Equipment SEL#15.
14
(2)
Digital sampling storage oscilloscope SEL#23.
15
(3)
Digital DC voltmeter SEL#22
16
(4)
Zero-level encoder/decoder SEL#46.
To verify that terminal equipment signals the network upon entering the off-hook state.
17
18
19
20
21
12.9.4 Equipment States Subject to Test
22
12.9.5 Test Procedure
23
24
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26
12.9.5.1
(1)
Connect the companion terminal equipment and the digital DC voltmeter to the tip
and ring leads of the EUT as shown in Figure 12.9.5.1-1.
27
(2)
Connect the digital DC voltmeter across the tip and ring leads of the EUT.
28
29
(3)
Connect the companion terminal equipment (e.g. a telephone) to the called station
under test.
30
(4)
Connect channel 1 of the storage oscilloscope (between ring lead and ground) to the
Place the TE in an off-hook state in response to an incoming call.
Test Procedure for Analog DID
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EUT.
2
3
(5)
Connect channel 2 of the storage oscilloscope (between ring lead and ground) to the
called station under test.
4
(6)
Originate a direct inward dialing call from the companion terminal equipment.
5
(7)
Monitor the EUT line loop polarity with the digital DC voltmeter.
6
7
8
(8)
Observe and record with the storage oscilloscope the elapsed period between the
time the called PBX station goes off-hook to answer the call and the time that the
EUT transmitted the line reversed answer supervision signal to the network.
9
10
(9)
Ensure that the line reversed answer supervision state maintains for the duration of
the call.
11
12
13
(10)
Repeat steps (6) through Step (9) for each call answering mode (i.e. answered by
the attendant, answered by a recorded message, forwarded call to another trunk,
etc).
14
15
16
12.9.5.2
(1)
Connect the TE to the test circuit of Figure 12.9.5.2-1.
17
18
(2)
Activate the A&B bits on the Zero Level encoder to simulate an incoming call on the
Reverse Battery DSO Channel under test.
19
20
(3)
Monitor the A&B bits transmitted by the TE and the Tip and Ring leads of the called
station.
21
22
23
(4)
Observe and measure the elapsed period between the time that the called station
goes off-hook to answer the call and the time that the TE transmitted A&B bits’
changes to answer supervision status.
24
25
(5)
Ensure that the A&B bit status remains in the answer supervision mode for the
duration of the call.
26
27
28
(6)
Repeat steps (2) through (5) for each call answering mode as specified by the
requirements, i.e. answered by the attendant, answered by a recorded message,
forwarded call to another trunk, etc.
Test Procedure for Digital DID
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30
12.9.6 Alternative Methods
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None suggested.
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12.9.7 Suggested Test Data
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12.9.8 Comments
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15
State whether the TE complies with this requirement.
This requirement applies only to equipment with Direct Inward Dialing interfaces.
Figure 12.9.5.1-1. Analog Direct Inward Dialing
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Note: This procedure shows using the oscilloscope to monitor the “A” and “B” bits. This may be done
by many means (e.g. a function within the zero level encoder/decoder).
Figure 12.9.5.2-1 1.544 megabits per second (Mb/s) Direct Inward Dialing
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11
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13 Connectors
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21
A contact interface that uses gold as the principal contact interface material needs to
meet the requirements and test methods in TIA-1096. The gold contact interface
definition in TIA-1096 is not intended to limit the gold contact interface to one that is
produced by a plating process. Gold contact interfaces produced by other processes
such as "cladding" that meet all the requirements of TIA-1096 for material quality,
thickness, density, porosity and surface roughness are to be considered the same as an
acceptable plated gold interface.
22
23
24
25
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28
29
30
In Docket No. 88-57, the FCC requested the Electronics Industries Association (EIA) to
develop a procedure for demonstrating the equivalency of alternative contact materials
to hard gold for 6 and 8 position connectors. In 1989, TIA Subcommittee TR-41.9
included such a procedure in its Telecommunications Systems Bulletin EIA/TIA TSB-31
on suggested Part 68 test methods. Requirements and test methods for demonstrating
the equivalency of alternative contact materials to hard gold are now provided in TIA1096.
Environmental and operational considerations require the use of contact interface
materials that result in a quality electrical connection. A quality electrical connection is
corrosion resistant and provides low noise and low contact resistance under normal
network operating conditions. Because of its unique characteristics, gold has typically
been used for this type of application. To allow for advances in technology, the FCC
permitted the use of non-gold interface materials so long as they were compatible with
each other and with gold, and of equivalent performance to gold.
13.1 Gold Contact Interface
13.2 Non-gold Contact Interface
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14 OTHER TYPES OF DSL TERMINAL EQUIPMENT
14.1 Metallic Signals TIA-968-A-3, 4.5.9.2.1 and TIA-968-A-4, 4.5.9.2.4
4
5
6
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14.1.1 Background
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14.1.2 Purpose
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14.1.3 Equipment
33
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38
This section currently only provides test procedures for SHDSL, ESHDSL, HDSL2, and
HDSL4 terminal equipment. Similar procedures may be applicable to other types of DSL
terminal equipment.
SHDSL, ESHDSL, HDSL2, and HDSL4 terminal equipment transmit significant power in
and above the voiceband and do not support the use of analog splitting technology for
coexistence on the same pair with voiceband services. Therefore, the analog voiceband
signal power limits in TIA-968-A are not applicable to SHDSL, ESHDSL, HDSL2, or
HDSL4 terminal equipment. Likewise, SHDSL, ESHDSL, HDSL2, and HDSL4 terminal
equipment would not ordinarily conform to the signal power specifications for any of the
other services or interfaces defined in section 4.5 of TIA-968-A.
To verify that the PSD is below the mask and to verify total signal power transmitted to
the network is properly limited.
(1)
Vector analyzer SEL#62
(2)
Hi-pass filter SEL#63
(3)
Balun transformers SEL#64, #65, #66
(4)
Artificial line SEL#67
NOTE: Refer to Section 5.3 for equipment details.
14.1.4 Equipment States Subject to Test
Transmitting continuously at all line data rates at maximum transmit power.
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14.1.5 Procedure
Measure the First PSD Segment & Total Power:
(1)
Connect the EUT (TU-R) to the companion unit (TU-C) as shown in Figure 14.11.
(2)
Using the artificial line, allow the EUT and TU-C to synchronize at maximum
power. When the DSL link has trained up, cause the EUT to continue to transmit
constantly without connection to the TU-C.
(3)
Connect the EUT (TU-R) to the measurement equipment as shown in Figure
14.1-2.
(4)
Set the vector analyzer frequency range and band power markers at 1 kHz (start)
and 2 MHz (stop). Resolution bandwidth = 10 kHz, Averaging time  10
seconds, Reference level: -20 dBm/Hz, dB/div: 10 dB and Autorange.
If applicable, load the PSD for the appropriate data rate (R), onto the vector
analyzer. Alternatively, comparison with the PSD mask can be done later, if your
vector analyzer lacks this capability.
24
25
26
27
28
29
30
Note: See comments for PSD masks.
(5)
Notes:
31
32
33
34
35
36
37
38
39
40
41
42
Measure and record the PSD and total power between 1 kHz and 2 MHz. No
filter is required.
(1)
For HDSL2 the band power markers would be set to 1 kHz and 350 kHz for the total power
measurement.
(2)
For HDSL4 set the vector analyzer start frequency at 200 Hz (start) and the band power
markers to 200 Hz and 307 kHz for the total power measurement, using the SEL#65 balun.
Measure the Second PSD Segment:
(6)
Insert a high-pass filter (in accordance with the table below) into the setup BNC)
is needed for the balun with most active filters, since they have high input
impedance.
(7)
Set the vector analyzer frequency range in accordance with the following table.
There is some overlap with the range covered in steps (3) though (5), but it is
often necessary to “close in” on this part of the signal with a filter to eliminate the
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pass band signal, and with a lower range setting.
Resolution bandwidth = 10 kHz, Averaging time  10 seconds, Reference level: 50 dBm/Hz, dB/div: 10 dB and Autorange.
If applicable, load the PSD mask for the appropriate data rate (R), onto the vector
analyzer. Alternatively, comparison with the PSD mask can be done later, if your
vector analyzer lacks this capability.
Measure and record the PSD as follows:
Technology
12
13
14
15
16
17
SHDSL (16-TCPAM)
500 kHz to 10 MHz
ESHDSL
HDSL2
HDSL4
500 kHz to 10 MHz
500 kHz to 10 MHz
2MHz to 10 MHz
High Pass Filter Setting
R < 2Mbps = 350 kHz
R > 2Mbps = 600 kHz
fint – 100kHz (Note 2)
350 kHz
350 kHz
Notes:
(1) The start frequency on the analyzer and the cut-off frequency on the filter can be adjusted as
necessary, keeping in mind that the effects of the filter are not within the window of
measurement.
18
19
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23
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27
28
29
30
Frequency Range
(2) fint is the frequency where the two functions governing PSDMASK SHDSL(f) intersect. fint may be
approximated by the following formulas:
16-TCPAM = (R+8)/3
32-TCPAM = (R+8)/4
Measure sliding 1 MHz window (WS) power criteria:
(8)
Without changing the setup from step (7), measure the total power in
accordance with the following table . If the reading is less than -50 dBm, stop
and record. If the reading is greater than -50 dBm, break into smaller windows of
1MHz, and record the highest reading from all windows.
Technology
SHDSL (16-TCPAM)
ESHDSL (16-TCPAM)
ESHDSL (32-TCPAM)
HDSL2
HDSL4
1 MHz Sliding Window Frequency Range
1.1 MHz to 10 MHz
fint to 10 MHz
fint to 10 MHz
3.1 MHz to 10 MHz
Not Applicable
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Measure the Third PSD Segment from 10 MHz to 30 MHz (12 MHz for ESHDSL):
(9)
Use balun SEL#66 and filter settings as appropriate (see note (4) of Figure 14-1).
(10)
Set the vector analyzer frequency range and band power markers at 10 MHz
(start) and 30 MHz (stop). Resolution bandwidth = 100 kHz (10 kHz for
ESHDSL), Averaging time  10 seconds, Reference level: -50 dBm/Hz, dB/div:
10 dB and Autorange.
If applicable, load the PSD mask for the appropriate data rate (R), onto the vector
analyzer. Alternatively, comparison with the PSD mask can be done later, if your
vector analyzer lacks this capability.
15
Note: It may be necessary to break this band up further, depending on the instruments selected.
16
17
18
19
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21
22
23
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25
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27
(11)
Measure and record the PSD between 10 MHz and 30 MHz (with the exception
of ESHDSL that ends at 12 MHz).
28
29
30
31
32
33
34
35
36
37
14.1.6 Alternative Method
38
39
40
41
42
43
14.1.7 Suggested Test Data
Measure sliding 1 MHz window (WS) power criteria in the 10 MHz-30 MHz band (12
MHz for ESHDSL):
(12)
Without changing the setup from step (11), use the band power markers to
measure the total power in the window from 10 MHz to 30 MHz (12 MHz for
ESHDSL). If the reading is less than -50 dBm, stop and record. If the reading is
greater than -50 dBm, break into smaller windows of 1 MHz, and record the
highest reading from all windows.
A spectrum analyzer (SEL #57) may be used instead of the Vector Analyzer. A high
pass filter is preferred for measurements above the operating band. The signal power
may be calculated by integrating the PSD over the operating band. The PSD may be
compared against the limit by using a spreadsheet or other software applications. The
spreadsheet may also be used to calculate the total power over a 1 MHz sliding
window.
(1)
Plots of the PSD for each line rate with the limit line shown on each graph.
(2)
Total Signal Power Level.
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(3)
14.1.8 Comments
(1)
Watch the dynamic range on each measurement. Make sure proper dynamic
range is selected for each measurement.
(2)
Filter type should ideally yield a 0dB gain, flat, in all areas of measurement. The
filter is present only to prevent the strong passband signal from overloading the
front end of the analyzer, and reducing its ability to range down.
(3)
Equipment that is classified as G.SHDSL according to clauses 5.4.2 and 6.3.2 of
T1.417-2003, the PSD mask (SHDSLM(f)) can be calculated from the following:
2

  f 


sin 
K
f
  sym 
1
SHDSL




2
SHDSL M ( f )   135
f sym
 f 




1  
f 


 sym 

4
1.5
0.5683  10  f ,

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

MaskedOffsetdB( f )

1
10


10
,
f

f
int
12

f 


f 3db 


f int  f  1.1MHz

MaskedOffsetdB(f) is defined as:
f f

1  0.4  3dB
MaskedOffsetdB( f )  
f 3dB

1

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Line Data Rate and Baud Rate if applicable.
,
f  f 3dB
,
f  f 3dB
fint is the frequency where the two functions governing SHDSLM(f) intersect in the
range 0 to fsym. KSHDSL, fsym, f3dB, and the line bit rate LBR are defined in Table 15
of T1.417-2003. The G.SHDSL PSD and total average power is measured with a
termination of 135 Ohms.
(4)
Equipment that is classified as HDSL2 (SMC 4) according to clause 5.3.4 and
6.2.4 of T1.417-2003, the PSD mask can be determined from Table 6 and Figure
5 of T1.417-2003. The HDSL2 PSD and total average power is measured with a
termination of 135 Ohms.
(5)
Equipment that is classified as HDSL4 according to clause 5.4.3 and 6.3.3 of
T1.417-2003, the PSD mask can be determined from Table 18 and Figure 15 of
T1.417-2003. The HDSL2 PSD and total average power is measured with a
termination of 135 Ohms.
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(6)
ESHDSL PSD mask can be determined from clause 4.5.9.2.4 of TIA-968-A-4.
The ESHDSL PSD and total average power is measured with a termination of
135 Ohms.
TU-R
(EUT)
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13
Companion
(TU-C)
Figure 14.1-1 Test Configuration to Establish Data Mode
TU-R
(EUT)
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Artificial line
(9kft 26 AWG)
Balun
Transformer
High Pass
Filter
Vector
Analyzer
Notes:
(1)
In practice, two transformers are typically used. One for 1kHz < f < 10 MHz, and another for 5
MHz < f < 30MHz. (There is some overlap in measurements).
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(2)
In practice, two settings are used. The filter is set to high-pass, 350 kHz for measurements in
the 500 kHz < f < 10 MHz band, for data rates below 2Mbps. The filter is set to high-pass, 600
kHz for measurements in the 700 kHz < f < 10 MHz band, for data rates above 2Mbps.
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(3)
No high-pass filter is used for 1 kHz < f < 500 kHz because this is in the passband.
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(4)
A high-pass filter may or may not be needed for 10 MHz < f < 30 MHz, depending on the
dynamic range of your instrument for these frequencies. If a filter is needed, use the same
settings as for the 500 kHz/700 kHz < f < 10MHz band.
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Figure 14.1-2 Test Configuration to Measure PSD and Total Power
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14.2 Longitudinal Output Voltage Limits TIA-968-A-3 and TIA-968-A-4, 4.5.9.2.3
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14.2.1 Background
Longitudinal output voltage (LOV) limits complement PSD limits by restricting the
amplitude of common mode signals much like the PSD limits restrict the amplitude of
the equipment’s differential mode signals. LOV limits are necessary, as common mode
signals tend to couple more readily than differential mode signals in multi-line, twisted
pair cable plant. In other words, LOV limits are necessary to limit crosstalk.
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14.2.2 Purpose
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14.2.3 Equipment
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14.2.4 Equipment States Subject to Test
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14.2.5 Procedure
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To verify that the longitudinal output voltage is below the limit.
(1)
Vector analyzer SEL#62
Note: Refer to Section 5.3 for equipment details.
Transmitting continuously at its highest signal power and upstream line data rate.
(1)
Condition the EUT to transmit at it highest upstream signal power level and line rate
as described in 14.1.5 steps (1) and (2).
(2)
Connect the EUT to the test circuit of Figure 14.2-1.
(3)
Set the vector analyzer frequency range at 1 kHz (start) and 2.5 MHz (stop) and set
the band power markers to 1 kHz and the upper -30 dB frequency, relative to peak
PSD (“Operating Band”). For SHDSL at its highest data rate, this would be 565.5
kHz. Resolution bandwidth = 3 kHz, Averaging time  1 second, Reference level: 30 dBV, dB/div: 10 dB and Autorange.
For HDSL2 refer to Table 6 of T1.417-2003 to determine the frequency range of
the “Operating Band.”
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For HDSL4 refer to Table 18 of T1.417-2003 to determine the frequency range of
the “Operating Band.”
For ESHDSL refer to Clause 4.5.9.2.3 of TIA-968-A-4 to determine the frequency
range of the “Operating Band.”
(4)
If reading is less than -50 dBV between band power markers, stop and record. If
the reading is greater than -50 dBV, break into smaller windows of 3 kHz, and
record the highest reading from all windows. Apply a correction factor of -1.3 dB to
discrete readings obtained with a 3 kHz bandwidth for comparison against the LOV
limit as specified over a 4 kHz bandwidth.
(5)
Set the vector analyzer band power markers from the upper -30 dB (relative to peak
PSD) frequency to 4  the upper -30 dB frequency. For SHDSL at its highest data
rate, this would be 565.5 kHz to 2262 kHz.
(6)
If reading is less than -80 dBV between band power markers, stop and record. If
the reading is greater than -80 dBV, break into smaller windows of 3 kHz, and
record the highest reading from all windows. Apply a correction factor of –1.3 dB to
discrete readings obtained with a 3 kHz bandwidth for comparison against the LOV
limit as specified over a 4 kHz bandwidth.
(7)
Repeat steps (3) though (6) for each of the data rates that the EUT can support.
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14.2.6 Alternative Method
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14.2.7 Suggested Test Data
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14.2.8 Comments
A spectrum analyzer (e.g. SEL #57) may be used instead of the Vector Analyzer. If the
spectrum analyzer does not have a 1 Mohm input impedance, then a correction factor
may be necessary.
(1)
Plot of the LOV with the limit line shown.
(2)
Line Data Rate and Baud Rate if applicable.
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6
(1)
For this requirement, the operating band is the range of frequencies between the
lower and upper -30 dB points (relative to peak PSD) of the signal passband as
determined from the PSD masks.
(2)
Take care in the construction of the LOV test fixture. Test leads from the fixture to
the EUT should be kept as short as possible to minimize RF ingress.
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24
NOTES:
(1)
The resistor values in Figure 14.2-1 are in ohms.
(2)
If the EUT does not have a ground connection or exposed grounded surface, it
should be placed upon a ground plane that is also connected to earth ground
(the same ground shared by the vector analyzer).
Figure 14.2-1 LOV TEST FIXTURE & CONNECTION DIAGRAM
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2
14.3 Transverse Balance TIA-968-A-3, 4.6.5
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4
5
6
14.3.1 Background
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14.3.2 Purpose
See Subclause 10.1.1
To determine transverse balance of SHDSL, HDSL2 and HDSL4 EUTs.
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12
14.3.3 Equipment
(1)
Spectrum analyzer SEL#34
13
(2)
Tracking generator SEL#39.
14
NOTE: Refer to Subclause 5.5 for equipment details.
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18
14.3.4 Equipment States Subject to Test
19
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22
14.3.5 Procedure
(3)
Connect the EUT to the test circuit of Figure 10.2-1 with the 135 ohm calibration test
resistor in place.
23
24
(2)
Set the spectrum analyzer and tracking generator to the appropriate frequency
ranges: (see comment 1 and 2)
Active state with appropriate grounding applied and the EUT transmitter turned off.
25
(a)
SHDSL EUT - 200 Hz to 490 kHz
26
(b)
HDSL2 EUT - 200 Hz to 422.1 kHz
27
(c)
HDSL4 EUT - 200 Hz to 493.6 kHz
28
(4)
Follow steps (3) through (13) in subclause 10.2.5.
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14.3.6 Comments
(1)
For the purposes of this requirement, the applicable operating range is defined
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as the entire range of frequencies between the highest and lowest frequencies
having PSD values within 20 dB of the peak PSD. Thus, the applicable frequency
range for transverse balance testing varies depending upon the supported PSD
masks.
(2)
Alternatively, a narrower frequency range may be used for SHDSL EUT that is
defined by the points at which the measured power spectral density (PSD) is 20
dB down from the maximum level associated with both the maximum data rate of
the upstream and downstream signals.
(3)
The longitudinal termination is defined in TIA-968-A-3, clause 4.6.5. Metallic
source impedance and metallic voltage to be used for transverse balance
measurements of SHDSL, HDSL2 and HDSL4 terminal equipment is 135 ohms
(ZM) and 0.367 V (VM) for each of the supported PSD masks.
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15 HEARING AID COMPATIBILITY
15.1 Hearing Aid Compatibility – Magnetic Field Intensity 47 CFR, 68.316
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15.1.1 Background
The United States Congress has legislated that persons using hearing aids with
magnetic pickups shall have reasonable access to the National Telephone Network. All
telephones imported and manufactured after August 16, 1989 must be hearing aid
compatible. Cordless telephones were exempted until August 16, 1991 must be HAC.
Mobile phones are exempted, except in business applications.
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15.1.2 Purpose
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18
19
15.1.3 Equipment
(1)
Bandpass filter SEL#5.
20
(2)
Sinewave frequency generator SEL#27.
21
(3)
Hearing aid probe assembly SEL#29.
22
(4)
True rms AC voltmeter SEL#40.
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(5)
Zero level encoder/decoder for all interface types under test (e.g. T1, ISDN) SEL #32
25
26
27
15.1.4 Equipment States Subject To Test
Normal off-hook talking condition.
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15.1.5 Test procedure
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15.1.5.1 Axial Field Intensity and Frequency Response (Reference Figure 1, EIA504 as contained in 47 CFR, 68.316).
To determine the magnetic field characteristics of hearing aid compatible handsets to ensure
adequate magnetic coupling.
Note: Refer to subclause 5.5 for equipment details.
(1) Connect the telephone under test as shown in Figure 12-1-1 for analog telephones,
Figure 12-1-2 for digital telephones, Figure 12-1-3 for proprietary and special use
telephone or Figure 12-1-4 for IP-based telephones.
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(2) Set the input at 1000 Hz across the 10 ohm resistor of the matching pad to -10
dBV for analog telephones or (-3) dBV for ISDN telephones. For proprietary,
special use and IP-based telephones, an appropriate test circuit and test level is
to be used that produces the same acoustic level (nominal (+0) dBPa) with the
receive volume control set to its nominal gain level.
14
15
(4) Determine the appropriate graph from the measured axial field intensity (Figure 4A
or 4B, EIA-504 as contained in 47 CFR, 68.316).
16
17
(5) Measure the frequency response and compare the computed value to the
appropriate graph.
18
19
20
(6) The axial component of the magnetic field directed along the measurement axis
and located at the measurement plan, is to be greater than (-22 dB) relative to 1
A/m at 1000 Hz.
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24
(7) For receivers with axial field that exceeds (-19) dB relative to 1 amp per meter
(A/m), the frequency response of the axial magnetic field intensity over the range of
300 Hz to 3300 Hz is to fall within the acceptable region of 47 CFR, 68.316, Figure
4A.
(3) Position the telephone handset receiver and probe coil for a maximum axial reading
and record the field intensity with the true rms AC voltmeter or the dynamic signal
analyzer. When testing the IP-based telephones (e.g. VoIP telephones), ensure
the duration of the test signals are longer than the packet delay (generally ranging
from 100 ms to 300 ms) so the true rms AC voltmeter or the dynamic signal
analyzer can capture the maximum axial field intensity readings at each of the
measurement frequencies.
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15.1.5.2
Radial Field Intensity and Frequency Response (Reference Figure 1,
EIA-504 as contained in 47 CFR, 68.316).
(1)
Connect the telephone under test as shown in Figure 12-1-1 for analog telephones,
Figure 12-1-2 for digital telephones, Figure 12-1-3 for proprietary & special use
telephone or Figure 12-1-4 for IP-based telephones.
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34
35
36
(2)
Set the input at 1000 Hz across the 10 ohm resistor of the matching pad to -10 dBV
for analog telephones or (-3) dBV for for ISDN telephones. For proprietary and
special use telephones (e.g. IP-based telephones), an appropriate test circuit and
test level is to be used that produces the same acoustic level (nominal (+0) dBPa)
with the receive volume control set to its nominal gain level .
37
38
39
(3)
Position the telephone handset receiver and probe coil for a maximum radial reading
and record the field intensity with the true rms AC voltmeter or the dynamic signal
analyzer. When testing the IP-based telephones (e.g. VoIP telephones), ensure the
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duration of the test signals are longer than the packet delay (generally ranging from
100 ms to 300 ms) so the true rms AC voltmeter or the dynamic signal analyzer can
capture the maximum radial field intensity readings at the four measurement points
in 90-degree intervals.
5
6
(4)
Determine the appropriate graph from the measured radial field intensity as directed
in paragraph 4.3 of EIA-504 as contained in 47 CFR, 68.316.
7
8
9
10
(5)
The radial component of the magnetic field as measured at 4 points 90 degrees
apart, and at a distance greater than or equal to 16 mm from the measurement axis
is to be greater than -27 dB relative to 1 amp per meter (A/m), for an input of (-10)
dBV at 1000 Hz. Reference 47 CFR, 68.316, subclause 5.5.
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14
(6)
For receivers with axial field that exceeds (-22) dB relative to 1 amp per meter (A/m),
the frequency response of the axial magnetic field intensity over the range of 300 Hz
to 3300 Hz is to fall within the acceptable region shown below. Reference 47 CFR,
68.316, Figure 4B.
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15.1.6 Alternative Methods
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15.1.7 Suggested Test Data
24
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26
15.1.7.1
(1)
Input in dBV.
27
(2)
Output in dBV.
28
(3)
Normalizing factor relative to 1000 Hz.
29
(4)
Calculated field intensity in dB relative to 1 Ampere/meter.
30
(5)
Frequency.
31
(6)
Output in dBV for each frequency.
32
(7)
Net change in dBV relative to 1000 Hz for each frequency.
None suggested.
All measurements are relative to 1 Ampere/meter.
Axial field intensity and frequency response
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15.1.7.2
Radial field intensity and frequency response
(1)
Input in dBV.
4
(2)
Output in dBV.
5
(3)
Measurement angle.
6
(4)
Normalizing factor relative to 1000 Hz.
7
(5)
Calculated field intensity in dB relative to 1 ampere/meter.
8
9
10
11
15.1.8 Comments
(1)
A chart recorder may be used to plot the data.
12
(2)
The probe coil output may be amplified, if needed.
13
14
15
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18
(3)
For telephone sets which provide the ability to adjust the receive amplitude, the EUT
can be deemed to be hearing aid compatible if the requirements of this subclause
are met at any one of the available volume settings. For proprietary, special use and
IP-based telephones, the volume control may be readjusted after the input level
necessary to produce 0 dBPa acoustic output has first been established with the
volume control gain set to its nominal level.
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29
(4)
For Helmholz coil, built in accordance with IEEE standard 1027 is required to
calibrate the hearing aid probe. The calibration procedure, in clause 5 of IEEE
Standard 1027 is recommended. The integrators in subclause 4.2 and subclause
6.5.3 of IEEE Standard 1027 are not used when making the frequency response
measurements. The requirements in Figure 4A and Figure 4B of IEEE Standard
1027 include the 6 dB per octave characteristic of the hearing aid probe coil. Any
deviation from the 6 dB per octave slope noted during the calibration procedure
using the Helmholz coil is to be included in the measurements. The hearing aid
voltage at 1000Hz is to be used as the 0 dB level in Figure 4A and 4B. In other
words, the frequency response curve passes through the 0 dB, 1000 Hz point of the
figures.
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Feeding Circuit
890 ohm
1 uF
> 2H
400 ohm
Sinewave
Generator
-10 dBV
10 ohm
1250 ohm
2W
Analog Telephone
Under test
Telephone Handset
Receiver
Note 1
48 V
Probe Coil
Optional
Bandpass Filter
Level
Recorder
True RMS
Voltmeter
Note 1.
The measurement axis is to be paralleled to the reference axis but may be displaced from
that axis by a maximum of 10 mm.
Note 2.
The battery feed circuit replaces the 2.7 km loop of 26 AWG cable.
Figure 15.1-1 Setup for testing 47 CFR, 68.316 HAC for Analog Telephone
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890 ohm
Sinewave
Generator
-3 dBV
10 ohm
ISDN
Telephone
Reference
Codec
ISDN
Telephone
Interface
ISDN Telephone
Under test
Telephone Handset
Receiver
Note 1
Probe Coil
Optional
Bandpass Filter
Level
Recorder
True RMS
Voltmeter
Note 1.
The measurement axis is to be paralleled to the reference axis but may be displaced from
that axis by a maximum of 10 mm.
Note 2.
The ISDN telephone reference codec replaces the 2.7 km loop of 26 AWG cable.
Figure 15.1-2 Setup for testing 47 CFR, 68.316 HAC for ISDN Telephone
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43
Circuit “A”
Feeding Circuit
Circuit “B”
Loop Simulator
2 uF
Circuit “C”
DC Blocking Circuit
2 uF
> 2H
400 ohm
2 uF
> 2H
400 ohm
48 V
2 uF
2 uF
2 uF
Proprietary Telephone
Reference codec
Circuit
“C”
Proprietary Telephone
Under test
Host system
T1 Zero-loss codec
Telephone Handset
Receiver
T1 Interface
Sinewave
Test
Signal
Generator
(Note 2)
Note 1
Probe Coil
Circuit
“A”
Loop start Interface
Proprietary
Telephone
Interface
Optional
Bandpass Filter
Circuit
“B”
Analog telephone
Interface
Level
Recorder
True RMS
Voltmeter
Note 1.
The measurement axis is to be paralleled to the reference axis but may be displaced from
that axis by a maximum of 10 mm.
Note 2.
The test signal generator level is to be set to produce (+0) dBPa at the telephone handset
receiver with the receive volume control set to its nominal gain level.
Figure 15.1-3 Setup for testing 47 CFR, 68.316 HAC for Proprietary & Special use
Telephone
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Circuit “A”
Feeding Circuit
Circuit “B”
Loop Simulator
2 uF
Circuit “C”
DC Blocking Circuit
2 uF
> 2H
400 ohm
2 uF
> 2H
400 ohm
48 V
2 uF
2 uF
Circuit
“C”
Sinewave
Test
Signal
Generator
2 uF
T1 Zero-loss codec
IP-based Telephone
Under test
T1 / IP
Gateway
Circuit
“A”
Loop start / IP
Gateway
Circuit
“B”
Analog telephone / IP
Terminal Adapter
10/100 Base-T
Ethernet Hub
Telephone Handset
Receiver
Note 1
Probe Coil
(Note 2)
Level
Recorder
Optional
Bandpass Filter
True RMS
Voltmeter
Note 1.
The measurement axis is to be paralleled to the reference axis but may be displaced from
that axis by a maximum of 10 mm.
Note 2.
The test signal generator level is to be set to produce (+0) dBPa at the telephone handset
receiver with the receive volume control set to its nominal gain level.
Figure 15.1-4 Setup for testing 47 CFR, 68.316 HAC for IP-based Telephone
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15.2 Hearing Aid Compatibility - Volume Control 47 CFR, 68.317
15.2.1 Background
The HAC Act required the FCC to establish regulations that would ensure reasonable
access to telephone service by persons with hearing disabilities. The FCC requires
hearing aid compatible telephones to provide volume control.
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18
15.2.2 Purpose
19
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21
15.2.3 Equipment
(1)
Optional 100 Hz Bandpass filter SEL#5.
22
23
24
25
26
(2)
Zero level encoder/decoder for all interface types under test (e.g. T1, ISDN) SEL #32
(3)
Test loops or commercially available artifical loop equivalent to 2.7 km and 4.6 km
#26 AWG non-loaded cable SEL#50.
27
28
(4)
Artificial ear SEL#51 for testing telephones with handsets that seal on this type of
artificial ear.
29
30
(5)
Artificial ear SEL#69 for testing telephones with handsets that do not seal on artificial
ear SEL#51.
31
(6)
Standard microphone SEL#52.
32
(7)
Microphone measuring amplifier SEL#53.
33
(8)
100 Hz to 5000 Hz sinewave frequency generator SEL#54.
34
35
(9)
AC voltmeter with an input impedance greater than 100 kohm for bridging
measurements or equal to 900 ohm for terminated measurements SEL#55.
To determine the Receive Objective Loudness Rating (ROLR) of telephone handset or
headset to ensure it complies with the upper and lower ROLR limits required by
ANSI/TIA-470-A for analog telephones or ANSI/TIA-579 for digital telephones when the
receive volume control is at its normal unamplified level and provides 12 dB of gain
minimum and up to 18 dB of gain maximum through the receiver of the handset or
headset of the telephone when the receive volume control is set to its maximum volume
setting.
Note: Refer to subclause 5.5 for equipment details.
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2
3
4
5
Note: Refer to subclause 5.5 for equipment details.
15.2.4 Equipment States Subject To Test
Normal off-hook talking condition.
6
7
8
9
10
15.2.5 Test procedure
(1)
Connect the telephone under test as shown in Figure 13.2.1 for analog telephones,
Figure 15.2-2 for ISDN telephones, Figure 15.2-3 for proprietary & special use
telephone or Figure 15.2-4 for IP-based telephones.
11
12
13
14
15
(2)
Place the handset receiver on artificial ear SEL#51 if a seal can be achieved
between the handset surface and the rim of the artificial ear without the use of
sealing putty or similar materials. If a seal cannot be achieved on artificial ear
SEL#51, place the handset receiver on artificial ear SEL#69 using the low leak
condition specified in ANSI/TIA-470.110-C.
16
17
18
19
20
21
22
23
24
25
26
27
(3)
The ROLR of the telephone under test is to first be determined with the receive
volume control at its normal unamplified level. If the manufacturer does not define a
"nominal volume level", either by some marking on the phone (e.g., label at a slide
switch detent position) or by some explanation in the user manual, the minimum
volume control setting is to be used as the normal unamplified level if the phone
meets the requirements of ANSI/TIA-470-A for analog telephones and ANSI/TIA-579
for ISDN, proprietary & special use and IP-based telephones. If the telephone at its
minimum volume control setting does not meet the required standards, the volume
control is to be increased until it does. The least volume control setting that meets
the ANSI/TIA-470-A / ANSI/TIA-579 requirements would then be defined as the
normal unamplified level. If the manufacturer does identify the "nominal volume
level", then that position has to be used as the starting point.
28
29
30
31
32
33
34
35
36
(4)
The ROLR of the telephone under test is to be determined by first measuring the
receive frequency response according to IEEE 269-2002 using the test circuit of
Figure 7 for analog telephone or Figure 13 for ISDN, proprietary & special use and
IP-based telephone. The ROLR is then calculated from the measured frequency
response as specified in IEEE 661-1979 (R1998). The performance of handset
receiver is generally independent of the position (vertical, horizontal face up or down)
of the handset. If the telephone being measured uses a carbon transmitter and the
receiver characteristics depend on the transmitter resistance, the conditioning
procedure specified in IEEE 269-2002 should be followed.
37
38
(5)
The battery feeding bridge circuit for analog telephone is to be as shown in Figure 1
of IEEE 269 standard.
39
(6)
The reference codec, the zero level encoder/decoder and the analog telephone / IP
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2
terminal adapter is to be capable of encoding or decoding analog signals with zero
loss for the ISDN, proprietary & special use and IP-based telephone under test.
3
4
5
6
(7)
The artificial ear is to be the IEC coupler for supra-aural earphones as described in
ANSI S3.7, Method for coupler calibration of earphones. The pressure response of
the microphone is to be used in determining the sound pressure generated in the
coupler by the receiver.
7
8
9
(8)
A laboratory standard pressure microphone according to ANSI S1.15 is to be used
for measuring the sound pressure generated in the artificial ear. The sensitivity of
the microphone should be constant over the frequency range of 100 Hz to 5000 Hz.
10
11
12
13
(9)
The frequency response characteristics of the microphone amplifier should be
constant over the frequency range from 100 Hz to 5000 Hz. The input-output
characteristics of this amplifier should be linear for the range of sound pressure
levels to be measured.
14
15
16
17
18
(10)
Measurements of ROLR for analog telephone is to be made for loop conditions
represented by 0, 2.7 and 4.6 km of 26 AWG non-loaded cables or equivalent. No
variation in loop conditions is required for ISDN, proprietary & special use and IPbased telephones since the receive level of ISDN, proprietary & special use and IPbased telephones are independent of loop length.
19
20
21
22
23
24
25
26
27
28
29
30
(11)
The sinewave frequency generator is to sweep the frequency range logarithmically
from 100 to 5000 Hz. The sweep rate is to be such that one complete transverse of
the 100 to 5000 Hz band requires approximately 10 seconds. The generator output
is to be adjusted to an open circuit voltage of 0.316 volt (i.e. (-10) dB relative to 1
volt) from a 900 ohm source. The electric source and the measurement circuit
should have the capability of operating linearly up to a level of approximately 1 volt.
When testing the IP-based telephones (e.g. VoIP telephones), because of the packet
delay (generally ranging from 100 ms to 300 ms) in the 10/100 base-T Ethernet hub
or the IP network, the test signal from the sinewave frequency generator should be
synchronized correctly with the tracking optional bandpass filter and its duration
should be long enough for the measuring amplifier and the level recorder to capture
the maximum readings at each of the measuring frequencies.
31
32
33
(12)
The AC voltmeter is to have ranges from 0.01 volt to 10 volt (full scale reading), with
an input impedance greater than 100 kohm for bridging measurements or equal to
900 ohm for terminated measurements.
34
35
36
37
38
39
(13)
Determine the ROLR for each of the applicable loop conditions representing 0, 2.7
and 4.6 km of 26 AWG non-loaded cables or equivalent over the frequency range
300 to 3300 Hz according to IEEE 661 standard. The ROLR is to fall between the
upper and lower limits as defined in subclause 4.1.2 of ANSI/TIA-470-A for analog
telephones or defined in subclause 4.3.2.2 of ANSI/TIA-579 for ISDN, proprietary &
special use and IP-based telephones.
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2
3
4
5
6
7
8
(14)
Adjust the volume control of the telephone under test to its maximum volume
setting. Repeat steps (2) through (11), the ROLR is to be increased by at least 12
dB minimum and 18 dB maximum. Verify that the 12 dB of minimum gain is
achieved without significant clipping of the test signal. The 18 dB of receive gain
may be exceeded provided the amplified receive capability automatically resets to
nominal gain when the telephone is caused to pass through a proper on-hook
transition in order to minimize the likelihood of damage to individuals with normal
hearing.
9
10
11
(15)
The ROLR value determined for the maximum volume control setting should be
subtracted from that determined for the nominal volume control setting to determine
compliance with the gain.
12
13
14
15
(16)
If the distortion measured in step (13) is significant, and the gain is greater than 12
dB, the volume control of the telephone under test should be adjusted to its lowest
setting that gives at least 12 dB of gain relative to the normal unamplified level as
determined in step (2), without significant clipping of the test signal.
16
17
18
19
20
21
22
23
15.2.6 Alternative Methods
24
25
26
27
28
ROLR (IEEE 661) = RLR (ITU-T P.79) + 51 dB
This relationship may be used to determine if RLR values obtained according to the
methods in TIA-470.110-C and TIA-810-B comply with Part 68 criteria specified in terms
of ROLR.
29
30
31
15.2.7 Suggested Test Data
(1)
State the type of artificial ear used for the tests.
32
33
(2)
If the test results were determined as ITU-T P.79 RLR values, show those values
and the conversion to ROLR values.
34
35
(3)
State whether the telephone with receive volume control complies with each of the
conditions specified in 47 CFR, 68.317.
36
37
38
(4)
State whether the ROLR of the telephone measured at 0, 2.7 and 4.6 km complies
with the upper and lower ROLR limits required by of ANSI/TIA-470 for analog
telephones or ANIS/TIA-579 for ISDN, proprietary & special use and IP-based
Although 47 CFR, 68.317 specifies the receive volume control requirement in terms of
ROLR as defined in IEEE 661-1979 (R1998), current industry standards TIA-470.110-C
(replaces TIA-470-A) and TIA-810-B (replaces TIA-579) have shifted to measuring receive
loudness in terms of Receive Loudness Rating (RLR) as defined by ITU-T
Recommendation P.79. Annex G of TIA-470.110-C provides the following relationship
between these two loudness rating measures:
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telephones when the receive volume control is set to its normal unamplified level.
2
3
(5)
State whether the ROLR of the telephone measured at its maximum receive volume
control setting provides 12 dB of minimum gain and up 18 dB of maximum gain.
4
5
6
7
(6)
If the telephone measured at its maximum receive volume control setting exceeded
the 18 dB of receive gain, state if the amplified receive capability automatically resets
to nominal gain when the telephone is caused to pass through a proper on-hook
transition.
8
9
10
11
15.2.8 Comments
(1)
This requirement applies to telephones with receive volume control.
12
13
(2)
ROLR is a loudness rating value expressed in dB of loss, more positive values of
ROLR represent lower receive levels.
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Feeding Circuit
2 uF
> [email protected] Hz
100 mA dc
200 ohm
900 ohm
48 V
Sinewave
Generator
Artificial line-26AWG
Non-loaded cable
Analog Telephone
Under test
Telephone Handset
Rx
200 ohm
Artificial Ear
2 uF
> [email protected] Hz
100 mA dc
Optional
Bandpass Filter
dB Meter
or
Level Recorder
Measuring
Amplifier
Figure 15.2-1 Setup for testing 47 CFR, 68.317 HAC volume control for Analog
Telephone
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2
890 ohm
Sinewave
Generator
-3 dBV
10 ohm
ISDN
Telephone
Reference
Codec
ISDN
Telephone
Interface
ISDN Telephone
Under test
Telephone Handset
Rx
Optional
Bandpass Filter
Level
Recorder
3
4
5
6
7
8
9
10
11
12
True RMS
Voltmeter
Figure 15.2-2 Setup for testing 47 CFR, 68.317 HAC volume control for ISDN
Telephone
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Circuit “A”
Feeding Circuit
2 uF
Circuit “B”
Loop Simulator
2 uF
> 2H
400 ohm
Circuit “C”
DC Blocking Circuit
2 uF
> 2H
400 ohm
48 V
2 uF
2 uF
2 uF
Proprietary Telephone
Reference codec
Circuit
“C”
Proprietary Telephone
Under test
Host system
Telephone Handset
Rx
900 ohm
Sinewave
Generator
T1 zero-loss codec
T1 Interface
Artificial Ear
Circuit
“A”
Loop start Interface
Circuit
“B”
Analog telephone
Interface
Proprietary
Telephone
Interface
dB Meter
or
Level Recorder
2
3
4
5
6
7
8
9
10
11
Optional
Bandpass Filter
Measuring
Amplifier
Figure 15.2-3 Setup for testing 47 CFR, 68.317 HAC volume control for
Proprietary & Special use Telephone
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Circuit “A”
Feeding Circuit
2 uF
Circuit “B”
Loop Simulator
Circuit “C”
DC Blocking Circuit
2 uF
> 2H
400 ohm
2 uF
> 2H
400 ohm
48 V
2 uF
2 uF
Circuit
“C”
2 uF
T1 Zero-loss codec
IP-based Telephone
Under test
T1 / IP
Gateway
Telephone Handset
Rx
900 ohm
Circuit
“A”
Loop start / IP
Gateway
Circuit
“B”
Analog telephone / IP
Terminal Adapter
10/100 Base-T
Ethernet Hub
Artificial Ear
Sinewave
Generator
dB Meter
or
Level Recorder
2
3
4
5
6
7
Optional
Bandpass Filter
Measuring
Amplifier
Figure 15.2-4 Setup for testing 47 CFR, 68.317 HAC volume control for IP-based
Telephone
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2
3
4
16 MISCELLANEOUS
16.1 Limitations on Automatic Redialing 47 CFR, 68.318(b)
5
6
7
8
9
10
11
12
16.1.1 Background
13
14
15
16.1.2 Purpose
16
17
18
16.1.3 Equipment State Subject to Test
19
20
21
22
23
16.1.4 Equipment
24
25
26
27
16.1.5 Procedure
(1)
Consult the EUT manual to determine if the equipment has an automatic redial
feature. If it does, perform the following sequence of tests.
28
(2)
Configure the equipment for automatic redial testing.
It is possible for equipment to dial the same number continuously until there is an
answer. Since CO equipment is being utilized during this time, the FCC ruled that the
number of automatic redial attempts to the same number be limited to prevent network
harm. Repertory dialers that require manual activation for each attempt are not included
under this requirement. Emergency alarm dialers and dialers under external computer
control are exempt from this requirement.
To verify the automatic redialing characteristics of the EUT.
Automatic redial function.
(1)
(2)
(3)
Applicable loop simulator SEL#4.
Storage oscilloscope SEL#23.
Network Tone Generator SEL#68.
29
(a)
Connect the EUT to the circuit shown in
30
(b)
Figure 16.1-1.
31
(c)
Condition the EUT so that it can automatically redial a predetermined number.
32
33
(d)
Set the storage oscilloscope so that it triggers when the EUT goes off-hook
and records up to 70 seconds of activity.
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(3)
Conduct testing for the no answer condition.
2
(a)
Activate the automatic redial feature of the EUT.
3
4
(b)
Use the network tone generator to apply audible ringing to the EUT when
dialing is complete.
5
6
(c)
Using the storage oscilloscope, measure and record the time interval from the
end of dialing until the EUT goes back on hook.
7
8
(d)
Remove the audible ringing signal after the EUT goes back on hook and wait
for it to make another redial attempt.
9
10
11
(e)
Each time the EUT makes a subsequent redial attempt, repeat steps (3)(b)
and (3)(d). It is not necessary to repeat step (3)(c) for each successive redial
attempt.
12
(f)
Count and record the number of successive redial attempts.
13
14
(g)
Wait at least 60 minutes after the last apparent redial attempt to see if the
EUT makes another redial attempt in this time window.
15
16
(4)
Conduct testing for the busy tone condition by repeating steps (3)(a) through (3)(g)
while applying busy tone to the EUT instead of audible ringing.
17
18
(5)
Conduct testing for the reorder tone condition by repeating steps (3)(a) through
(3)(g) while applying reorder tone to the EUT instead of audible ringing.
19
20
21
(6)
For equipment that detects compatible terminal equipment at the called party end
(e.g., modems and fax machines), conduct testing for the condition where noncompatible terminal equipment answers.
22
(a)
Activate the automatic redial feature of the EUT.
23
24
(b)
Use the network tone generator to apply audible ringing to the EUT when
dialing is complete.
25
26
27
(c)
After two complete audible ringing cycles, replace the network tone generator
with a silent 600 ohm termination to simulate non-compatible equipment
answering the call.
28
(d)
Determine that the EUT goes back on hook.
29
30
(e)
Remove the 600 ohm termination and wait for the EUT to make another redial
attempt.
31
32
(f)
Each time the EUT makes a subsequent redial attempt, repeat steps (6)(b)
through (6)(e).
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(g)
2
3
(7)
4
(8)
Count and record the number of successive redial attempts.
Configure the equipment for dial delay testing by resetting the storage oscilloscope
so that it records up to 700 ms of activity when the EUT goes off hook.
Conduct testing for dialing delay.
5
(a)
Activate the automatic redial feature of the EUT.
6
7
(b)
For loop start equipment, apply dial tone to the EUT approximately 200 ms
after it goes off hook.
8
9
(c)
For ground start equipment, apply CO ground to the tip conductor
approximately 200 ms after the EUT goes of hook.
10
11
12
13
(d)
Using the storage oscilloscope, measure and record the time from the
application of dial tone or CO ground, as appropriate, until the start of dialing.
Also measure and record the time from when the EUT goes off hook to the
start of dialing.
14
15
16.1.6 Alternative Methods
16
None suggested.
17
18
19
20
16.1.7 Suggested Test Data
(1)
Number of successive dialing attempts to the same number when audible ringing is
received with no answer.
21
22
(2)
Number of successive dialing attempts to the same number when busy tone is
received.
23
24
(3)
Number of successive dialing attempts to the same number when reorder tone is
received.
25
26
(4)
Number of successive dialing attempts to the same number when the call is
answered by non-compatible equipment.
27
28
(5)
Time interval in seconds from the end of dialing until EUT goes back on hook when
audible ringing is received with no answer.
29
(6)
Time Interval in seconds from application of busy tone until EUT goes back on hook.
30
31
(7)
Time interval in seconds from application of reorder tone until EUT goes back on
hook.
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2
(8)
For loop start EUTs with automatic dial tone detection, time interval in milliseconds
from application of dial tone to start of dialing.
3
4
(9)
For ground start EUTs, time interval in milliseconds from the application of CO
ground on the tip conductor to the start of dialing.
5
6
(10)
For EUTs without automatic dial tone detection, time interval in milliseconds from
when the EUT goes off hook to start of dialing.
7
8
9
10
11
12
16.1.8 Comments
(1)
The process of conditioning the EUT so that it can automatically redial a
predetermined number may involve making a call attempt to that number and
receiving no answer.
13
14
15
16
17
18
(2)
The suggested level for application of dial tone is -16 dBm per frequency. The
suggested level for the application of busy tone and reorder tone is -27 dBm per
frequency. The suggested level for the application of audible ringing is -22 dBm per
frequency. These levels are typical of the levels the EUT will experience in the
network. They are 3 dB below the nominal level applied by the CO to account for
typical loop losses.
19
20
(3)
Use of pulse dialing mode (if EUT is so equipped) may facilitate measurement of the
start and end of dialing.
21
22
23
(4)
“Emergency alarm dialers” are dialers that are designed to dial out to a
predetermined number in the event of a fire, intrusion, medical, equipment failure, or
similar emergency.
24
25
26
27
28
29
30
31
(5)
“Dialers under external computer control” means that the dialer and the computer are
not the same product (i.e. may be purchased individually). They may be from one or
more manufacturers, and are connected via an interface cable or connector. An
example of such products is a stand-alone repertory dialer (capable of auto redialing)
connected to a desktop PC via a serial interface. “Dialers under external computer
control” does not mean things like a PC telephony card with a PSTN interface that
provides a complete telephony function, and can do network addressing (e.g.
FAX/modem card).
32
33
34
35
36
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Storage
Oscilloscope
EUT
Loop
Simulator
Network
Signal
Generator
1
2
3
4
5
Note 1.
6
Note 2.
7
8
9
Select the appropriate loop simulator for the interface of the EUT. Refer to the figures of
clause 1 of ANSI/TIA-968-A.
The oscilloscope should provide a balanced input.
Figure 16.1-1 Limitations on automatic redialing
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3
4
5
6
7
8
9
16.2 Line Seizure by Automatic Telephone Dialing Systems - 47 CFR, 68.318(c)
16.2.1 Background
The automatic telephone dialing systems referred to by this subclause are those
typically used for sequentially dialing through a list of telephone numbers and providing
a recorded message. The requirement that the equipment release the telephone line is
to ensure that the called party can gain access to that line in case of emergency.
10
11
12
13
14
16.2.2 Purpose
15
16
17
18
16.2.3 Equipment
19
20
21
22
16.2.4 Equipment States Subject to Test
23
24
25
26
16.2.5 Procedure
27
28
29
30
16.2.6 Alternative Methods
31
32
33
34
35
16.2.7 Suggested Test Data
36
37
16.2.8 Comments
To verify that the equipment releases the telephone line within the required time after
notification has been transmitted to it indicating that the called party has hung up.
None suggested.
Test any off-hook state.
None suggested. See comment (1).
None suggested.
Time for EUT to release the line after notification has been transmitted to it indicating
that the called party has hung up.
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
(4)
(5)
Specifying a clear test method to test this requirement is extremely difficult. This is
because the there is a large range of signals that can be transmitted toward the EUT
indicating that the called party has hung up. It is recommended that the test facility
devise a test method that is appropriate for the EUT so this parameter is measured
properly. This test method needs to be properly documented in the test facilities
procedures or the test report or both.
This requirement is not applicable to EUT that provides a redial function to the same
number. Refer to 47 CFR, 68.318(b).
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3
16.3 Telephone Facsimile Machines: Identification of the Sender of Messages
(FAX branding) – 47 CFR, 68.318(d)
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
16.3.1 Background
In 1992, the FCC issued rules requiring senders of telephone facsimile (FAX) machine
messages to identify themselves on all FAX messages, implementing provisions in the
Telephone Consumer Protection Act of 1991. In addition, manufacturers are required to
ensure that FAX equipment is capable of marking FAX messages with the required
identifying information. The intent of these rules is to control telemarketing nuisances
such as unsolicited commercial advertisements, automatic message dialers, and junk
FAX mail. These rules first appeared as 47 CFR, 68.318(c)(3) of the FCC rules, but
were later moved to 47 CFR, 68.318(d). In 1995, the FAX branding requirement was
extended to FAX modems.
47 CFR, 68.318(d) requires FAX machines manufactured on or after December 20,
1992, and FAX modems manufactured on or after December 13, 1995, to have the
capability to clearly mark or “brand” the following user provided identifying information in
a margin at the top or bottom of each transmitted page (e.g., in a “header” or “footer”):
21
- the date and time that the message was sent;
22
23
- an identification of the business, other entity, or individual sending the
message; and,
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
- the telephone number of the sending machine or of such business, other entity,
or individual.
The FCC requires a statement in the customer instructions that describes this
requirement and tells the user how to set up the FAX machine to produce this header or
footer. A sample of this statement is shown in TSB-129-A, clause 8.2.13 (see also
comment at 16.3.7(1) below).
Prior to the privatization of the 47 CFR Part 68 equipment approval process in 2001, the
FCC required manufacturers to attest that their FAX machines had the capability of
marking each transmitted page with the required information. This method of
demonstrating compliance with 47 CFR, 68.318(d) is still acceptable. If compliance with
47 CFR, 68.318(d) is demonstrated by testing, then the method provided in 16.3.3
through 16.3.5 is recommended.
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3
4
5
6
7
8
16.3.2 Purpose
The purpose of this procedure is to account for the FAX branding capability requirement
in 47 CFR, 68.318(d). This can be accomplished by either a manufacturer’s attestation
or testing. A sample attestation letter is provided in 16.3.7, comment 2. The
recommended test procedure is described in 16.3.3 through 16.3.5. Recommended
information to include in the final test report is described in 16.3.6.
9
10
11
12
13
16.3.3 Equipment
14
15
16
17
16.3.4 Equipment States Subject to Test
18
19
20
21
22
23
24
25
26
27
28
29
30
16.3.5 Procedure
31
16.3.6 Suggested Test Data
(4)
(5)
Additional facsimile machine.
Network simulator or compatible network connections.
Originating a FAX call.
(6)
If a letter attesting conformity with 47 CFR, 68.318(d) is not provided, follow the
customer instructions to enter the current time and date, a company or user name,
and user telephone number in the FAX EUT.
(7)
Connect the FAX equipment to the telephone network simulator or compatible
network connection and cause the EUT to transmit a multipage (two or more
pages) facsimile message to another facsimile machine.
(8)
Confirm that the required identifying information is printed on each page of the
received facsimile message.
32
33
34
(4)
Include either an attestation letter or a statement that the FAX equipment
demonstrated through testing that it was capable of sending the identifying
information required by 47 CFR, 68.318(d).
35
36
(5)
Include a copy of the customer instructions explaining how to enter the current
time and date, a company or user name, and user telephone number.
37
38
(6)
Include a sample multipage facsimile message showing the required information
in a margin at the top or bottom of each page.
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1
2
3
4
5
6
16.3.7 Comments
(1)
TSB-129-A, clause 8.2.13, states that the customer information for facsimile (FAX)
equipment must contain the following wording:
7
8
9
10
11
12
13
14
15
The Telephone Consumer Protection Act of 1991 makes it unlawful for any
person to use a computer, FAX machine, or other electronic device, to send
any message unless such message clearly contains in a margin at the top or
bottom of each transmitted page or on the first page of the transmission, the
date and time it is sent and an identification of the business or other entity, or
other individual sending the message and the telephone number of the
sending machine or such business, other entity, or individual. (The telephone
number provided may not be a 900 number or any other number for which
charges exceed local or long distance transmission charges.)
16
17
18
19
20
In order to program this information into your FAX machine, you should
complete the following steps: [Insert here instructions for programming the
equipment and the required information or the page where it can be found].
(2)
Sample FAX branding attestation letter (on applicant’s letterhead):
21
To whom it may concern:
22
23
24
25
[Insert name of applicant] attests that this approved facsimile
equipment is capable of marking the user provided identifying
information required by 47 C.F.R. 68.318(d) in a margin at the top
or bottom of each transmitted page.
26
Signed: [Signature of responsible party] Date: [Insert date]
27
28
29
30
31
32
33
34
35
Name:
Address:
(3)
[Print name of responsible party]
[Insert address of responsible party]
Manufacturers are advised to put the setup instructions in an easily accessible
location and to make it easy for their customers to comply with this requirement.
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1
2
16.4 Equal Access to Common Carriers - 47 CFR, 68.318(e)
3
4
5
6
7
8
9
10
16.4.1 Background
11
12
13
14
15
16.4.2 Purpose
16
17
18
19
16.4.3 Equipment
20
21
22
23
16.4.4 Equipment States Subject to Test
24
25
26
27
28
29
16.4.5 Procedure
30
31
32
33
16.4.6 Alternative Methods
34
35
36
37
38
16.4.7 Suggested Test Data
As specified in 47 CFR, 68.318(e) any equipment or software manufactured or imported
on or after April 17, 1992, and installed by any aggregator shall be technologically
capable of providing consumers with access to interstate providers of operator services
through the use of equal access codes.
To verify that the equipment provides the capability to access to interstate providers of
operator services through the use of equal access codes.
None suggested.
None suggested.
(9)
Examine the customer instructions for the EUT or software in question and
determine if it has the capability of providing consumers with access to interstate
providers of operator services through the use of equal access codes.
(10)
None suggested.
(7)
State whether EUT is capable of providing consumers with access to inter-state
providers of operator services through the use of equal access codes.
(8)
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1
2
3
4
5
6
7
8
9
10
11
16.4.8 Comments
(2)
Due to huge diversity of different manufacturer’s implementation of this capability in
their equipment or software, it is extremely difficult to provide a single evaluation
method to address all situations. It is recommended that the test facility devise a
technique that is appropriate for the EUT so this parameter is evaluated properly.
This technique needs to be properly documented in the test facilities procedures or
the test report or both.
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APPENDIX A, TEMPLATES for DIGITAL PULSES
A.1 Templates for Subrate and PSDS Digital Pulses
Figure A1-1 through Figure A1-12 provide drawings of the templates for the
subrate digital pulse shape limitations. Figures A1-13 and A1-14 provide
drawings of the templates for the PSDS digital pulse shape limitations. These
drawings include the specified amplitudes, pulse widths, attenuations and
filtering. In each case the 10% tolerance specified in ANSI/TIA-968-A, subclause
4.5.8.1.6 is included in the figure. Pulse shapes may be obtained which do not
fall within these limits. In shapes which do not fall within these limits, further
comparison to the actual criteria contained in ANSI/TIA-968-A, subclause
4.5.8.1.6 may be necessary in order to determine compliance to these
requirements.
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Figure A1-1. Subrate, Pulse Template, 2.4 kilobits per second (kb/s)
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Figure A1-2. Subrate, Pulse Template, 3.2 kilobits per second (kb/s)
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Figure A1-3. Subrate, Pulse Template, 4.8 kilobits per second (kb/s)
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Figure A1-4. Subrate, Pulse Template, 6.4 kilobits per second (kb/s)
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Figure A1-5. Subrate, Pulse Template, 9.6 kilobits per second (kb/s)
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Figure A1-6. Subrate, Pulse Template, 12.8 kilobits per second (kb/s)
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Figure A1-7. Subrate, Pulse Template, 19.2 kilobits per second (kb/s)
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Figure A1-8. Subrate, Pulse Template, 25.6 kilobits per second (kb/s)
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Figure A1-9. Subrate, Pulse Template, 38.4 kilobits per second (kb/s)
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Figure A1-10. Subrate, Pulse Template, 51.2 kilobits per second (kb/s)
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2
s
1.4
l
1.6
t
1.8
o
1.2
V
1
0.8
0.6
0.4
0.2
0
0.0
4.0
8.0
12.0
16.0
Time (us)
Figure A1-11. Subrate, Pulse Template, 56.0 kilobits per second (kb/s)
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2
1.6
t
s
1.8
l
1.4
o
1.2
V
1
0.8
0.6
0.4
0.2
0
0.0
1.7
3.5
5.2
7.0
8.7
10.5
12.2
Time (us)
Figure A1-12. Subrate, Pulse Template, 72.0 kilobits per second (kb/s)
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3
s
2.5
V
o
lt
2
1.5
1
0.5
0
0
1
2
3
4
5
6
7
Time (µs)
Figure A1-13. PSDS Type II Pulse Template, 144 kilobits per second (kb/s)
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3
s
2.5
V
o
lt
2
1.5
1
0.5
0
0
1
2
3
4
Time (µs)
5
6
7
Figure A1-14. PSDS Type Iii Pulse Template, 160 kilobits per second (kb/s)
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A.2 Templates for ISDN PRA and 1.544 Mb/s Digital Pulses
Figures A2-1 and A2-2 show examples of possible templates as derived from the
limits given in ANSI/TIA-968-A, subclause 4.5.8.2.2. Pulse shapes may be
obtained which do not fall within these limits. In shapes which do not fall within
these limits, further comparison to the actual criteria contained in ANSI/TIA-968A subclause 4.5.8.2.2 may be necessary in order to determine compliance to
these requirements.
The template for the Option A output pulse is shown in ANSI/TIA-968-A, Figure
4.6. The template for the Option B output pulse was obtained by passing the
pulse defined for Option A through the following transfer function:
Vout
n2 S 2  n1S  n0

3
Vin d 3 S  d 2 S 2  d1S  d 0
where:
n0 = 1.6049x106
n1 = 7.9861x10-1
n2 = 9.2404x10-8
d0 = 2.1612x106
d1 = 1.7223
d2 = 4.575x10-7
d3 = 3.8307x10-14
s = j2f
f = frequency (Hz)
The template for pulse Option C was obtained by passing the wave form
obtained for pulse Option B through the same transfer function.
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Figure A2-1. 1.544 megabits per second (Mbps), Pulse Template, Option B
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Figure A2-2. 1.544 megabits per second (Mbps), Pulse Template, Option C
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APPENDIX B, EXAMPLE CALCULATIONS OF WAVEFORM ENERGY
LEVELS
2
x
E( j)   ( j)
n 1
where:
x
tn
Vn
R
=
=
=
=
Vn
 t n
R
Number of time intervals
Time of "nth" interval in seconds
Voltage for time interval n
Terminating resistance
To calculate the energy in the waveform shown in Figure B1-1:
(1)
Divide the duration (T) into x number of time intervals (tn). The
greater
the number of intervals, the more accurate the results. In the example
calculation, 16 time intervals were used. The intervals do
not have to
be equal. However, intervals of equal width allow simplification of the
calculation.
(2)
From the graph of the waveform, determine the voltage level for
interval.
(3)
Calculate the energy level using the equation. If t was selected so that the
intervals are of equal width, the equation becomes:
x
t
E( j) 
  Vn2
R n 1
where:
x = Number of time intervals
t = Time interval in seconds
Vn = Voltage for time interval n
R = Terminating resistance
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E( j) 
1  103 sec
 (602  112 2  1322  1402  134 2  122 2  110 2  982
500
 852  722  602  492  392  302  222  152 )
E(j) = 0.26 joules
Figure B1-1. Calculation of Energy Levels
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Appendix C, Alternate Transverse Balance, Digital EUT
A.3 Background
This annex offers a current based measurement technique, where a ratio of the
stimulating metallic current to the resulting longitudinal current represents the
effective transverse balance. This ''ratio of currents'' technique uses completely
passive toroidal current probes as the detection elements in conjunction with a
balanced balun transformer as shown in Figure C-1.
The test fixture exhibits substantial immunity to parasitic effects of capacitance,
inductance, and laboratory RF noise, while maintaining an extremely accurate
response in the non-traditional telephony frequency bands of ISDN and DSL. The
magnetic devices are available as ''off the shelf devices'', and they are directly
compatible with typical 50 ohm BNC connections to measurement equipment
such as a network or spectrum analyzer. Additionally, the passive devices
completely isolate the analyzer from the Equipment Under Test (EUT), leaving
absolutely no paths through ground or isolation resistors. The transverse balance
of the EUT easily plots as a logarithmic ratio of currents on the screen of an
analyzer for immediate analysis.
Transverse Balance = 20log
i 1+ i 2
i 1-i 2
- 6dB
In effect, the transverse balance is a ratio in dB of an applied metallic current and
the resulting longitudinal current. The presence of longitudinal current is
undesirable, and it is well known that such current may disturb adjacent circuits.
Therefore it is highly desirable to identify equipment that emits longitudinal
current.
A ratio of currents measurement easily and accurately achieves the primary goal
of identifying current absent from a desired equal current flow from tip to ring
during metallic stimulation, across the frequency band of interest. The absent or
lost current, referred to as longitudinal current iL, is quantified by the toroid that
measures i1-i2. The stimulating metallic current iM is quantified by the toroid that
measures i1+i2. The term i1+i2 is nearly twice the metallic current, and could
more accurately be expressed as (i1+i2)-iL, but the iL term is several orders of
magnitude less than iM, and therefore iL is neglected in the numerator.
Neglecting iL in the numerator of the transverse balance equation compensates
for the analyzer measuring twice the metallic current, in effect the user subtracts
6dB from the analyzer's results to get the true transverse balance. The
mathematical error introduced by this test configuration (where iL is neglected in
the numerator) is insignificant, and can be shown mathematically to be less than
0.136dB for an analyzer plot that shows 36dB for a given frequency (transverse
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balance of 30dB). For the quantified range for pass fail criteria (35dB minimum),
a worst case error of 0.136dB at 30dB is completely acceptable. Of course, as
the quality of the EUT improves, the error reduces proportionately, so the error at
35dB is truly negligible.
A.4 Purpose
To determine transverse balance of digital EUT, by using a ratio of currents.
A.5 Equipment
(3)
A precision 50 ohm to 100 ohm balun with greater than 60dB of longitudinal
balance with respect to the center tap on the 100 ohm side (similar to North
Hills 0311LB) SEL#XX.
(4)
Two of the same model precision wound toroidal current monitors (similar to
Pearson 4100) SEL#XX.
(5)
Spectrum analyzer: input impedance 50 ohm, frequency range from 100 Hz
to at least one octave above the maximum test frequency, sensitivity of 0.1
mV or better, resolution <1 Hz, accuracy (+2) dB..
A.6 Equipment States Subject To Test
Active state with appropriate grounding applied.
Note: Terminal equipment may require special attention to ensure it is properly configured for
this test. For example, if the equipment would normally be connected to ac power
ground, cold water pipe ground, or if it has a metallic or partially metallic exposed
surface, then these points should be connected to the test ground plane. Similarly, if
the EUT provides connections to other equipment through which ground may be
introduced to the equipment, then these points should be connected to the test ground
plane. Equipment which does not contain any of these potential connections to ground
should be placed on a conductive plate which is connected to the test ground plane
(see comment (1)); this applies to both non-powered and ac-powered equipment.
A.7 Procedure
(1)
Assemble the circuit shown in Figure C-1 and connect the equipment to the
circuit as shown. The frequency range for the analyzer should be at least
200Hz < f < 2MHz.
(2)
Set the analyzer's 50 ohm tracking generator output to (+3) dB (equivalent to
0dB into 100 ohms). With switch S2 set in position B, terminate the tip
conductor to ground while the ring conductor is open. This represents the
worst case transverse balance condition, and there is no metallic current flow.
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Switch S1 is then toggled and the ground termination is attached to the
opposite conductor, again a worst case transverse balance condition. For
both positions of S1 the analyzer should read about 0dB for any frequency in
the specified transverse balance frequency band. Essentially this process
verifies conductivity and wiring for the test circuit.
(3)
With switch S2 in position A, the analyzer should read within 1dB of 36dB for
the termination shown (Za=100, Zb=10K, and Zc=1158), which is a
transverse balance of 30dB. Toggle switch S1 and the analyzer should read
within 1dB of the previous measurement. Should this not be the case, it is
then necessary to add the variable capacitors and adjust them to achieve at
most a 1dB difference for the two positions of S1, for the termination shown.
These caps, when properly adjusted, compensate for the imperfections in the
transformer's windings and possible parasitic effects such as interwinding
capacitance.
(4)
After the test fixture is calibrated as described above, set switch S2 to position
C and measure the transverse balance of the EUT. The pass/fail limits in dB
for transverse balance versus frequency using the ratio of currents method
should be the same as the limits specified for the voltage method described in
the primary text of 47 CFR Part 68. However, as is true of any alternative
method of test the burden of proof of correlation between the standard and
alternative method lies upon the user of the alternative methodology.* To get
the true transverse balance for the EUT, reduce the display on the analyzer
by 6dB.
*Test methodologies and illustrative circuits specified in ANSI/TIA-968-A have been
determined by historically understood use and recommended practice to provide
ease of test and lab to lab repeatability, while they may not always be the most
expedient or technically appropriate way to perform a test in a specific situation.
Correlating test results with this alternative current method might include lab data
for both voltage and current methods under conditions which can be expected to
yield clean data with each (i.e., at the low frequency end of the test range and/or
away from frequencies and/or levels which might suggest the voltage method is
questionable).
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Figure C-1: Test Fixture To Measure Transverse Balance Using A Ratio Of
Currents
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Appendix D, Test Procedures for Passive Splitter Filters and Passive MicroFilters
D.1 Background
ADSL systems are designed to share the same loop facility with voice services.
When voice and data services share the same phone line, filters are usually
needed on the customer premises. Low-Pass Filters (LPFs) block highfrequency transients and impedance effects that result from voice service
operation (e.g., ringing transients, ring trip transients, and off-hook transients and
impedance changes) from reaching the ADSL modem. The LPF also blocks high
frequency ADSL signals from reaching voice terminal equipment which may be
affected by such frequencies.
The LPF function can be implemented either internally or externally to the ADSL
modem. When the LPF function is performed externally, the LPF is generally a
stand-alone device. There are many stand-alone LPFs on the market and they
come in different shapes and sizes. Most, but not all, have "ADSL" printed
somewhere on the device. There are two basic types of stand-alone LPFs – the
splitter filter and the micro-filter. The splitter filter is a centrally located in-line
LPF and micro-filters are distributed in-line LPFs.
D.2 Example of Splitter Filter
For the purposes of this evaluation, a splitter filter is a stand-alone, single line,
three port, wall mounted device that is usually installed on the customer’s side of
the Network Interface (NI) near the point where the phone line comes into the
customer premises. The Line Port of the splitter filter connects to the phone line
and the Splitter internally divides the phone line into separate voice and data
lines which appear at the Phone and ADSL Ports respectively. Splitter filters
used with ADSL modems always contain a low-pass filter (LPF) for the voice
frequency port and may or may not contain a high-pass filter (HPF) for the data
port. If the associated ADSL modem contains a HPF, then the splitter filter does
not need to provide a HPF on the data port. If the ADSL modem does not
contain a HPF, then use an external splitter filter with a HPF for the data port.
The splitter filters considered in this evaluation are wall mounted, have a metallic
cover, and are not powered from an external source and do not contain active
electronic components1 but rather consist entirely of passive components.2 Such
Splitters do not transmit internally generated signals or provide port to port
amplification of signals passing through the device. The performance standard
for splitter filters used in North America is ITU-T G.992.1 Annex E.2.
1 Active electronic components require an external source of power in order to operate.
2 Passive electronic components do not require an external source of power in order to operate. Examples
of passive components are wire wound inductors or transformers, capacitors, and resistors.
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D.3
Example of Micro-Filter
For the purposes of this evaluation, a micro-filter is a stand-alone, single line, two
port, non-wall mounted device installed on the customer’s side of the NI at each
jack where voice terminal equipment is connected to the phone line. The Line
Port of the micro-filter connects to the phone line and the Phone Port connects to
the customer’s voice equipment (e.g., telephone, FAX machine, etc.). The microfilters considered in this evaluation are encased in non-conductive plastic and
have no exposed conductive surfaces. In addition, micro-filters are not powered
from an external source and do not contain active electronic components but
rather consist entirely of passive components. The performance standard for
micro-filters used in North America is T1.421.
D.4 Applicable ANSI/TIA-968-A Technical Criteria from TSB-31-C Test
Matrix
Splitter filters and micro-filters are intended to be connected to lines with an
ordinary (analog, loop start) voice service and an ADSL-based data service.
Based on the test matrix associated with this document, the technical criteria with
an “X” in the loop start and ADSL columns of Table D-1 are applicable to terminal
equipment connecting to loop start interfaces and ADSL interfaces. The “Test
Splitter Filter” and “Test Micro-Filter” columns of Table D-1 indicate whether or
not a specific test needs to be performed on the splitter filters and micro-filters
described above. Rationale is given in each instance where compliance may not
need to be verified through testing.
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Table D-1 Technical Criteria for Splitter Filter and Micro-Filter Examples
ANSI/TIA-968-A Technical Criteria Applicable to Loop Start and ADSL Interfaces
Technical Criteria
4.2.1
Mechanical Shock
4.2.2
Surge A Metallic and Longitudinal
4.2.3
Surge B Metallic and Longitudinal
4.2.4
Power Line Surge
4.3
Leakage Current
4.4.1
Hazardous Voltage – General
4.4.2
Hazardous Voltage - Separation of Leads
4.4.5.2 Intentional Protective Paths to Ground
4.5.2.1.1 Signal Limits - Voiceband - Not Network Control Signals
4.5.2.1.2 Signal Power Limits - Voiceband - Network Control Signals
4.5.2.3.2 Signal Limits - Through Transmission Equipment – Data
4.5.2.4 Signal Power Limits - Voiceband Signal Power – Data
4.5.2.5.1 Through Transmission - Port To Port Amplification
4.5.2.5.1(7) Signal Power Limits - Through Transmission - SF cutoff
4.5.2.5.2 Signal Limits - Through Transmission - SF/Guard Band
4.5.3.1 Signal Limits – 3995-4005 Hz - Not Network Control Signals
4.5.3.2 Through Transmission Loss - 3995-4005 Hz vs 600-4000 Hz
4.5.4
Signal Limits – Non LADC Longitudinal Voltage 0.1 - 4 kHz
4.5.5.1 Signal Limits – Non LADC Metallic Voltage 4 kHz-30 MHz
4.5.5.2 Signal Limit - Non LADC Longitudinal Voltage 4kHz-6MHz
4.5.9.1.1 Signal Power Limits – ADSL – Total Signal Power
4.5.9.1.2 Signal Power Limits – ADSL – PSD
4.5.9.3 Signal Power Limits – ADSL - Longitudinal Output Voltage
4.6.2
Transverse Balance – Analog
4.6.3
Transverse Balance – ADSL
4.7.2.1 On-Hook Impedance Limits - DC resistance
4.7.2.3 On-Hook Impedance Limits - DC current during ringing
4.7.2.4 On-Hook Impedance Limits - AC impedance during ringing
4.7.4
On-Hook Impedance Limits - REN calculation
4.7.8
On-Hook Impedance Limits - Transitioning to off-hook state
4.8.1.1 Billing Protection - Call Duration for Data Equipment
4.8.1.2 Billing Protection - Call Duration for Data Applications
4.8.2
Billing Protection - On-Hook Signal Power
4.8.3
Billing Protection - Off-Hook Loop Current
4.8.4.1 Billing Protection - Signaling Interference Analog
6.
Connectors
Loop
Start
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
ADSL
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Splitter
Filter
No (1)
Yes
Yes
No (2)
Yes (3)
Yes
No (4)
No (5)
No (6)
No (6)
No (6)
No (6)
Yes (7)
No (6)
Yes
No (6)
Yes
No (6)
No (6)
No (6)
No (6)
No (6)
No (6)
Yes (8)
Yes
Yes
Yes
Yes
Yes
No (9)
No (6)
No (6)
No (6)
No
No (6)
Yes (10)
MicroFilter
Yes (1)
Yes
Yes
No (2)
No (3)
Yes
No (4)
No (5)
No (6)
No (6)
No (6)
No (6)
Yes (7)
No (6)
Yes
No (6)
Yes
No (6)
No (6)
No (6)
No (6)
No (6)
No (6)
Yes (8)
Yes
Yes
Yes
Yes
Yes
No (9)
No (6)
No (6)
No (6)
No
No (6)
Yes (10)
Note 1.
No, if the device is wall mounted, otherwise Yes.
Note 2.
It is assumed that the device has no power cord.
Note 3.
Yes, if the device has any of the test point combinations defined in ANSI/TIA-968A, clause 4.3, otherwise No,
Note 4.
It is assumed that the device has no power leads or leads to non-approved
equipment.
Note 5.
No, if the device has no intentional protective path to ground, otherwise Yes.
Note 6.
No, if the device does not connect to an external source of power, consists entirely
of passive components, and cannot internally generate signals or amplify through
signals, otherwise Yes.
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Note 7.
The RTE to PSTN requirement only.
Note 8.
On-hook requirement only if the device has no off-hook state.
Note 9.
No, if the device has no off-hook state, otherwise Yes.
Note 10.
Yes, if the device has a plug or jack or both, otherwise No.
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D.5
(1)
Test Methods for Splitter Filters
Mechanical Shock Simulation – Mechanical shock simulation is not
applicable if the device is wall mounted. If mechanical shock simulation is
applicable to the particular splitter filter under test, the simulation methods
would be no different than the methods used for other terminal equipment.
(2) Surge Simulations – The power line surge simulation is not applicable if the
device has no power cord. The methods for performing surge simulations
for splitter filters are no different than the methods used for other terminal
equipment. Surges should be applied with the splitter filter in all states that
can affect compliance with the requirements of ANSI/TIA-968-A with
equipment leads not being surged terminated in a manner that occurs in
normal use.
(3) Leakage Current Limitations – Leakage current limitations are applicable if
the splitter filter has conductive surfaces or any of the other test point
combinations specified in ANSI/TIA-968-A. The methods for testing leakage
current are no different than the methods used for other terminal equipment.
(4) Hazardous Voltage Limitations – The methods for checking for hazardous
voltage on the tip and ring leads of the splitter filter’s line port are no
different than the methods used for other terminal equipment.
(5) Signal Power Limitations – Except as explained below for the applicable
Through Transmission tests, signal power tests are not applicable when the
splitter filter consists entirely of passive components and does not internally
generate signals or amplify through signals. For the applicable Through
Transmission tests, the test signal should be applied to the Phone Port and
the measurement made at the Line Port. Repeat the test by transmitting the
test signal into the ADSL Port and measuring the signal at the Line Port.
(6) Transverse Balance – The transverse balance requirements of ANSI/TIA968-A, sections 4.6.2 and 4.6.3, should be tested on the Line Port in the
following states as listed in Table D-2 below:
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Table D-2 Splitter Filters Transverse Balance Test States
Port Under Test ADSL Port
Phone (Voice) Port
Line
Unterminated Unterminated
Line
Unterminated Terminated - Off-Hook
Line
Unterminated Terminated - On-Hook
Line
Terminated
Unterminated
Line
Terminated
Terminated - Off-Hook
Line
Terminated
Terminated - On-Hook
The following terminations should be used:
Phone on-hook termination = Figure 4.13 of ANSI/TIA-968-A-4 with R1
adjusted per the note in Figure 4.13.
Phone off-hook termination = Use Figure 4.9 of ANSI/TIA-968-A with R1
adjusted per the note in Figure 4.9.
ADSL termination = Figure 4.14 of ANSI/TIA-968-A-4.
(7) On-Hook Impedance Limits – The following tests should be performed with
both the Phone and ADSL Ports unterminated:
-
On-hook DC resistance requirement of ANSI/TIA-968-A, clause
4.7.2.1;
-
DC current during ringing requirement of ANSI/TIA-968-A, clause
4.7.2.3;
-
AC impedance during ringing requirement of ANSI/TIA-968-A, clause
4.7.2.4; and,
-
REN calculation requirement of ANSI/TIA-968-A, clause 4.7.4.
Note: The test methods for connectors associated with splitter filters are no different than the
methods used for other terminal equipment.
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D.6
Test Methods for Micro-Filters
(1)
Mechanical Shock Simulation – Mechanical shock simulation is applicable if
the device is not wall mounted. The methods for mechanical shock
simulation are no different than the methods used for other terminal
equipment.
(2)
Surges – The power line surge simulation is not applicable if the device has
no power cord. The methods for performing surge simulations are no
different than the methods used for other terminal equipment. Surges
should be applied with the micro-filter in all states that can affect compliance
with the requirements of TIA-986-A with equipment leads not being surged
terminated in a manner that occurs in normal use.
(3) Leakage Current Limitations – This test is not applicable if the device has no
conductive surfaces nor any of the other test point combinations specified in
ANSI/TIA-968-A. If the test is applicable, the methods are no different than
the methods used for other terminal equipment.
(4)
Hazardous Voltage Limitations – The methods for checking for hazardous
voltage on the tip and ring leads of the micro-filter’s line port are no different
than the methods used for other terminal equipment.
(5)
Signal Power Limitations – Except for applicable Through Transmission
tests, signal power tests are not applicable when the micro-filter consists
entirely of passive components and does not internally generate signals or
amplify through signals. For applicable Through Transmission tests, the
test signal should be applied to the Phone Port and the measurement made
at the Line Port.
(6) Transverse Balance – The transverse balance requirements of ANSI/TIA968-A, sections 4.6.2 and 4.6.3, should be tested in the following states as
listed in Table D-3 below:
Table D-3 Micro-Filters Transverse Balance Test States
Port Under Test Port Termination
Line Port
Phone Unterminated
Line Port
Phone Terminated - Off-Hook
Line Port
Phone Terminated - On-Hook
Phone Port
Line Unterminated
Phone Port
Line Terminated - Off-Hook
Phone Port
Line Terminated - On-Hook
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The same phone on-hook and off-hook terminations defined for splitter filter
transverse balance testing should be used for micro-filter transverse balance
testing. The ADSL modem termination defined for splitter filter transverse
balance testing is not used for micro-filter transverse balance testing.
(7) On-Hook Impedance Limits – The following tests should be performed with
the Phone Port unterminated:
-
On-hook DC resistance requirement of ANSI/TIA-968-A, clause
4.7.2.1;
-
DC current during ringing requirement of ANSI/TIA-968-A, clause
4.7.2.3;
-
AC impedance during ringing requirement of ANSI/TIA-968-A, clause
4.7.2.4; and,
-
REN calculation requirement of ANSI/TIA-968-A, clause 4.7.4.
Note: The test methods for connectors associated with micro-filter are no different than the
methods used for other terminal equipment.
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