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Transcript
PN-3-3602-RV3 to be published as TIA/TSB31-C
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Working Cover Page
Telecommunications –
Telephone Terminal Equipment Rationale and Measurement Guidelines for U.S. Network Protection
Draft 10g
October 25, 2004
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
TR-41, User Premises Telecommunications Requirements, under the sponsorship of
the Telecommunications Industry Association. 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. 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, Part 68
TIA-968-A
T1.TRQ.6-2001
The changes to this document from TSB-31-B are extensive due to the
restructuring of Part 68 and new technical criteria that have come into effect since TSB31-B was published. This document supercedes TIA-TSB-31-B and represents the
consensus of the formulating group.
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TR-41 COMMITTEE MEMBERS
{to include others who may have been
missed}
Larry Bell
Roger Hunt
Rafi Rahamim
Tim Lawler
Efrain Guevara
Gary Flom
Greg Slingerland
Peter Walsh
Bryan Skarbek
Tailey Tung
Cliff Chamney
Al Martin
Anh Nguyen
Trone Bishop
Steve Whitesell
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Adtran
ATLINKS
Broadcom Corporation
Cisco Systems
Industry Canada
Intertek Testing Services
Mitel Networks Corporation
Paradyne
Sharp Electronics
Siemens ICN
Sprint
Tyco Electronics
Underwriters Labs
Verizon
VTech
TR-41.9 GENERAL COMMITTEE MEMBERS
Organization Represented
Name of Representative
{ TR41.9 roster to be provided here}
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TABLE OF CONTENTS
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FOREWORD......................................................................................................................... I
3
TR-41 COMMITTEE MEMBERS ......................................................................................... II
4
TABLE OF CONTENTS ...................................................................................................... III
5
LIST OF FIGURES............................................................................................................ VIII
6
1
INTRODUCTION .......................................................................................................... 1
7
2
SCOPE ......................................................................................................................... 2
8
3
NORMATIVE REFERENCES ...................................................................................... 3
9
4
DEFINITIONS, ACRONYMS AND ABBREVIATIONS ................................................. 4
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16
5
GENERAL INFORMATION ........................................................................................ 10
17
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7
LEAKAGE CURRENT LIMITATIONS (ANALOG AND DIGITAL) TIA-968 PAR 4.3 . 34
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8
HAZARDOUS VOLTAGE LIMITATIONS 68.306 TIA-968-A PAR 4.4 ..................... 39
5.1
Safety Warning About The Procedures In This Document ................................................10
5.2
General Document Structure .............................................................................................10
5.3
Simulator Circuit Theory ....................................................................................................10
5.4
Test Conditions .................................................................................................................10
5.5
Suggested Equipment List (SEL) ......................................................................................11
5.6
Test Requirements Matrix .................................................................................................16
ENVIRONMENTAL SIMULATION TIA-968-A PAR 4.2............................................. 17
6.1
Sequencing of Environmental Simulations ........................................................................17
6.2
Mechanical Shock TIA-968-A Par 4.2.1...........................................................................22
6.3
Telephone Line Surge - Type A, Metallic. TIA-968-A Par 4.2.2.1 ...................................23
6.4
Telephone Line Surge - Type A, Longitudinal. TIA-968-A Par 4.2.2.2 .............................25
6.5
Telephone Line Surge - Type B, Metallic. TIA-968-A Par 4.2.3.1 ...................................27
6.6
Telephone Line Surge - Type B, Longitudinal. TIA-968-A Par 4.2.3.2 ..............................30
6.7
Power Line Surge TIA-968-A Par 4.2.4 ...........................................................................32
8.1
Hazardous Voltage Limitations, General TIA-968-A Par 4.4.1 .........................................39
8.2
Hazardous Voltage Limitations, E&M TIA-968-A Pars 4.4.1.1, 4.4.1.2, 4.4.1.3 ...............41
8.3
Hazardous Voltage Limitations, OPS TIA-968-A, 4.4.1.4 .................................................46
8.4
Hazardous Voltage Limitations, DID TIA-968-A Par 4.4.1.5 ............................................49
8.5
Hazardous Voltage Limitations, LADC TIA-968-A Par 4.4.1.6 .........................................51
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8.6 Ringdown Voiceband Private Line and Metallic Channel Interface
TIA-968-A Par
4.4.1.7.........................................................................................................................................53
8.7
Physical Separation of Leads TIA-968-A Paragraph 4.4.2 ................................................56
8.8
Ringing Sources TIA-968-A Par 4.4.4 .............................................................................58
8.9
Intentional Paths to Ground TIA-968-A Par 4.4.5.1 .........................................................64
8.10
9
Intentional Protective Paths to Ground ANSI/TIA-968-A, 4.4.5.2 ..................................67
SIGNAL POWER LIMITATIONS TIA-968, 4.5 ........................................................... 70
9.1
Voiceband Signal Power – Not Network Control signals TIA-968, 4.5.2.1 .........................70
9.2
Voiceband Signal Power - Network Control Signals TIA-968-A, 4.5.2.2 ...........................77
9.3 Through-Transmission Equipment – DC Conditions for On-Premises
TIA-968-A,
4.5.2.3.1......................................................................................................................................82
9.4
Through-Transmission Equipment – Data TIA-968-A 4.5.2.3.2 ......................................85
9.5
Voiceband Signal Power - Data TIA-968-A, 4.5.2.4..........................................................86
9.6
Through-Transmission – Port to Port Amplification TIA-968-A Par 4.5.2.5.1 ...................91
9.7
Through-Transmission - SF Cutoff TIA-968-A Par 4.5.2.5.1(7).......................................97
9.8
Through-Transmission - SF/Guard Bands TIA-968-A Par 4.5.2.5.2 ..............................100
9.9
Return Loss, Tie Trunk - Two Wire TIA-968-A, 4.5.2.6.1 ................................................106
9.10
Return Loss, Tie Trunk - Four Wire TIA-968-A, 4.5.2.6.2 ............................................109
9.11
Transducer Loss, Tie Trunk - Four Wire TIA-468-A, 4.5.2.6.3.....................................113
9.12
DC Conditions, OPS TIA-968-A, 4.5.2.7 .....................................................................117
9.13
Signal Power 3995 Hz - 4005 Hz TIA-968-A, 4.5.3.1 ...................................................120
9.14
Through Transmission – 3995-4005 Hz vs 600-4000 Hz TIA-968-A, 4.5.3.2 ..............124
9.15
Non-LADC Longitudinal Voltage – 0.1 - 4 kHz TIA-968 Par 4.5.4 ...............................128
9.16
Non-LADC Metallic Voltage - 4 kHz to 30 MHz TIA-968 Par 4.5.5.1 ...........................133
9.17
Non-LADC Longitudinal Voltage - 4 kHz to 6 MHz TIA-968 Par 4.5.5.2 ......................141
9.18
Metallic Voltage - 0.01 kHz to 6 MHz, LADC TIA-968-A Par 4.5.6.1, 4.5.6.2 .............150
9.18.1
Background ..............................................................................................................150
9.19
Longitudinal Voltage - 0.01 kHz to 6 MHz, LADC TIA-968-A Par 4.5.6.3 ...................162
9.20
Pulse Repetition Rate, Subrate TIA-968-A Par 4.5.8.1.1 ...........................................173
9.21
Encoded Analog Content TIA-968-A Pars 4.5.8.1.2, 4.5.8.1.8, 4.5.8.4.4 ...................174
9.22
Equivanent PSD for Maximum Output, Subrate TIA-968-A Par 4.5.8.1.3 ..................177
9.23
Average Power, Subrate, Non-Secondary Channel Rates TIA-968-A Par 4.5.8.1.4 ..178
9.24
Average Power, Subrate, Secondary Channel Rates TIA-968-A Par 4.5.8.1.5 ..........179
9.25
Pulse Template, Subrate and PSDS TIA-968-A Par 4.5.8.1.6 ...................................180
9.26
Average Power, Subrate TIA-968-A Par 4.5.8.1.7 .....................................................181
9.27
Pulse Repetition Rate, 1.544 Mb/s TIA-968-A Par 4.5.8.2.1 ......................................182
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9.28
Output Pulse Template, 1.544 Mb/s TIA-968-A Paragraphs 4.5.8.2.2 & 4.5.8.2.3 .......184
9.29
Output Power, 1.544 Mb/s TIA-968-A Par 4.5.8.2.4 ...................................................187
9.30
Unequipped Sub-rate Channels TIA-968-A, 4.5.8.2.6 ..................................................191
9.31
Pulse Repetition Rate, PSDS (Types II and III) TIA-968-A Par 4.5.8.3.1 ...................192
9.32
Pulse template, PSDS (Types II and III) TIA-968-A Par 4.5.8.3.2 ..............................193
9.33
Conditioning ADSL EUT to Transmit Continuously TIA-968-A Par 4.5.8.3.2 ..............194
9.34
Aggregate Signal Power, ADSL Terminal Equipment TIA-968-A Par 4.5.9.1............195
9.35
Power Spectral Density, ADSL Terminal Equipment TIA-968-A Par 4.5.9.2 ..............197
9.36
Longitudinal Output Voltage, ADSL Terminal Equipment TIA-968-A Par 4.5.9.3 .......207
9.37
Voiceband Signal Power - Non-approved external signal sources TIA-968-A-3, Para
4.5.2.2 211
9.38
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Voiceband Signal Power - Non-approved external signal sources TIA-968-A-3, 4.5.2.2215
TRANSVERSE BALANCE LIMITATIONS TIA-968 PAR 4.6 ............................... 219
10.1
Transverse Balance, Analog TIA-968-A Par 4.6.2 .....................................................219
10.2
Transverse Balance, Digital TIA-968-A Pars 4.6.3, 4.6.4 ...........................................225
ON HOOK IMPEDANCE LIMITATIONS TIA-968 PAR 4.7 ................................... 230
11.1
DC Resistance TIA-968 Pars 4.7.2.1 and 4.7.2.2.......................................................230
11.2
DC Current During Ringing TIA-968-A Pars 4.7.2.3 and 4.7.3.1 .................................235
11.3
AC Impedance During ringing (Metallic and Longitudinal) TIA-968-A Pars 4.7.2.4,
4.7.2.5, and 4.7.3.2 ...................................................................................................................238
11.4
REN Calculation TIA-968-A Pars 4.7.4 and 4.7.5........................................................243
11.5
OPS Ring Trip, PBX with DID TIA-968-A Par 4.7.6 ....................................................245
11.6
Transitioning to the Off-Hook State and Make-busy TIA-968-A Par 4.7.8 ..................248
11.7
Manual programming of Repertory Numbers, TIA-968-A, 4.7.8.1 ................................250
11.8
Automatic stutter dial tone detection TIA-968-A Par 4.7.8.2 ........................................252
BILLING PROTECTION TIA-968-A PAR 4.8 ........................................................ 255
12.1
Call Duration for Data Equipment, Protective Circuitry TIA-968-A Par 4.8.1.1 .............255
12.2
Call Duration for Data Applications, Terminal Equipment TIA-968-A Par 4.8.1.2 .........259
12.3
On-hook Signal Power, Analog TIA-968-A Par 4.8.2 ..................................................263
12.4
Off-Hook Loop Current TIA-968-A Par 4.8.3 ...............................................................267
12.5
Signaling Interference, Analog TIA-968-A Par 4.8.4.1................................................272
12.6
Signalling Interference, Digital TIA-968-A Par 4.8.4.2 ................................................276
12.7
On-Hook Signal Power, Subrate and 1.544 Mb/s TIA-968-A Pars 4.8.5 ....................280
12.8
Signalling duration, 1.544 Mb/s TIA-968-A Par 4.8.6 .................................................283
12.9
Operating Requirements for DID TIA-968-A, 4.8.7 .....................................................286
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MINIATURE PLUGS AND JACKS, 6 AND 8 POSITION TIA-968-A PAR 6......... 290
13.1
Gold Contact Interface .................................................................................................290
13.2
Non-gold Contact Interface ..........................................................................................294
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SHDSL, HDSL2, HDSL4 TERMINAL EQUIPMENT ............................................... 302
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APPENDIX A, TEMPLATES FOR DIGITAL PULSES ..................................................... 359
21
APPENDIX B, INFORMATIVE REFERENCES ............................................................... 377
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APPENDIX C, EXAMPLE CALCULATIONS OF WAVEFORM ENERGY LEVELS (INFORMATIVE)
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APPENDIX D, ALTERNATE TRANSVERSE BALANCE, DIGITAL EUT (INFORMATIVE)380
29
APPENDIX E, MODIFIED SO2 METHOD (INFORMATIVE) ........................................... 384
30
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APPENDIX F, INDUSTRIAL MIXED FLOWING GAS (INFORMATIVE) ......................... 385
14.1
Metallic Signals T1.TRQ.6, 4.1.1..................................................................................302
14.2
Longitudinal Output Voltage Limits T1.TRQ.6, 4.1.2 ....................................................308
14.3
Transverse Balance Requirements T1.TRQ.6, 4.2 ......................................................312
14.4
Longitudinal Output Voltage .........................................................................................314
14.5
Transverse Balance .....................................................................................................315
HEARING AID COMPATIBILITY ............................................................................ 314
15.1
Hearing-Aid Compatibility – Magnetic Field Intensity 68.316.......................................314
15.2
Hearing Aid Compatibility, Volume Control 68.317......................................................322
MISCELLANEOUS ................................................................................................. 330
16.1
Limitations on Automatic Redialing 68.318(b) ..............................................................330
16.2
Line Seizure by Automatic Telephone Dialing Systems - Part 68, 68.318(c)................334
16.3
Telephone Facsimile Machines – Part 68, Section 68.318(d) ......................................336
16.4
Equal Access to Common Carriers - Part 68, 68.318(e) ..............................................339
A.1
Templates for Subrate and PSDS Digital Pulses .........................................................359
A.2
Pulse Templates for ISDN PRA and 1.544 Mbps equipment .......................................374
D.1
Background ..................................................................................................................380
D.2
Purpose........................................................................................................................381
D.3
Equipment ....................................................................................................................381
D.4
Equipment States Subject To Test ...............................................................................381
D.5
Procedure ....................................................................................................................381
F.1
General............................................................................................................................385
F.2
Materials ..........................................................................................................................385
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F.3
Test Equipment ...............................................................................................................386
F.4
Safety and Health Considerations ...................................................................................387
F.5
Sample Preparation.........................................................................................................388
F.6
Procedure ........................................................................................................................389
F.7
Documentation ................................................................................................................392
F.8
Summary .........................................................................................................................392
F.9
Historical..........................................................................................................................392
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LIST OF FIGURES
Figure 6.1-1 Environmental Flowchart ..................................................................... 19
Figure 7-1. Leakage Current ....................................................................................... 38
Figure 8.2-1 M-Lead Contact Protection................................................................... 45
Figure 8.2-1 Ringing Sources, Two-Wire.................................................................. 61
Figure 8.2-2 Ringing Sources, Four-Wire ................................................................ 62
Figure 8.2-3 Ringing Protection ................................................................................ 63
Figure 8.4.1-1 Intentional Operational Paths to ground .......................................... 66
Figure 8.10-1 Intentional Protective Paths to Ground ............................................. 69
Figure 9.1-1. Voiceband Signal Power, Two-Wire.................................................... 74
Figure 9.1-2. Voiceband Signal Power, Four-Wire ................................................... 75
Figure 9.1-3. Voiceband Signal Power, E&M Tie ..................................................... 76
Figure 9.2-1. Network Control Signal Power, Two-Wire .......................................... 80
Figure 9.2-2. Network Control Signal Power, Four-Wire ......................................... 81
Figure 9.3-1. DC Conditions for Through Transmission ......................................... 84
Figure 9.5-1. Voiceband Signal Power, Data, TE ..................................................... 90
Figure 9.6-1 Through Transmission, Analog ........................................................... 94
Figure 9.6-2. Through Transmission, Digital ........................................................... 95
Figure 9.6-3. Digital EUT Arrangement for Figure 9.6-2 .......................................... 96
Figure 9.7-1. Single Frequency Cut-off..................................................................... 99
Figure 9.8-1. Through Transmission - SF Guard Bands, Analog ......................... 103
Figure 9.8-2. Through Transmission - SF Guard Bands, Digital .......................... 104
Figure 9.8-3. Digital EUT Arrangement for Figure 9.8-2 ........................................ 105
Figure 9.9-1. Return Loss, Two-Wire ...................................................................... 108
Figure 9.10-1. Return Loss, Four-Wire, T&R .......................................................... 111
Figure 9.10-2. Return Loss, Four-Wire, T1&R1 ..................................................... 112
Figure 9.11-1. Transducer Loss, Forward .............................................................. 115
Figure 9.11-2 Transducer Loss, Reverse ............................................................... 116
Figure 9.12-1. OPS DC Conditions .......................................................................... 119
Figure 9.13-1. Signal Power, 3995-4005 Hz, Internal Sources .............................. 123
Figure 9.14-1 Signal Power, 3995-4005 Hz vs 600-4000 Hz, Through Transmissio
.............................................................................................................................. 127
Figure 9.15-1. Voiceband Longitudinal Voltage ..................................................... 132
Figure 9.16-1. Non-LADC Metallic 4 kHz to 30 MHz ............................................... 139
Figure 9.16-2. Non-LADC Metallic 270 kHz to 30 MHz ........................................... 140
Figure 9.17-1. Non-LADC Longitudinal 4 kHz to 6 MHz ......................................... 147
Figure 9.17-2. Non-LADC Longitudinal 270 kHz to 6 MHz ..................................... 149
Figure 9.18-1. LADC Metallic 10 Hz to 4 kHz, T&R ................................................. 156
Figure 9.18-2. LADC Metallic 10 Hz to 4 kHz, T1 & R1 ........................................... 157
Figure 9.18-3. LADC Metallic 700 Hz to 270 kHz, T&R ........................................... 158
Figure 9.18-4. LADC Metallic 700 Hz to 270 kHz, T1&R1 ........................................ 159
Figure 9.18-5. LADC Metallic 270 kHz to 30 Mhz, T&R .......................................... 160
Figure 9.18-6. LADC Metallic 270 kHz to 30 MHz, T1&R1 ...................................... 161
Figure 9.19-1. LADC Longitudinal 10 Hz - 4 kHz, T&R........................................... 167
Figure 9.19-2. LADC Longitudinal 10 Hz to 4 kHz, T1 & R1 .................................. 168
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Figure 9.19-3. LADC Longitudinal 4 kHz to 270 kHz, T & R .................................. 169
Figure 9.19-4. LADC Longitudinal 4 kHz to 270 kHz, T1 & R1 .............................. 170
Figure 9.19-5. LADC Longitudinal 270 kHz to 6 MHz, T & R ................................. 171
Figure 9.19-6. LADC Longitudinal 270 kHz to 6 Mhz, T1 & R1 .............................. 172
Figure 9.21.1-1. 1.544 Mb/s, Encoded Analog Content ......................................... 176
Figure 9.27-1. 1.544 Mb/s, Pulse Repetition Rate ................................................... 183
Figure 9.28-1. 1.544 Mb/s, Pulse Template connection diagram ........................... 186
Figure 9.29-1. 1.544 Mb/s, Output Power................................................................. 190
FIGURE 9.34.5-1. AVERAGE SIGNAL POWER ........................................................ 196
FIGURE 9.35.5.1-1. PSD CONNECTION DIAGRAM FOR SEGMENTS 1 & 2 .......... 199
FIGURE 9.35.5.1-2. SAMPLE PSD PLOT FOR SEGMENT 1 .................................... 199
FIGURE 9.35.5.2-1. SAMPLE PSD PLOT FOR SEGMENT 2 .................................... 201
FIGURE 9.35.5.3-1. PSD CONNECTION DIAGRAM FOR SEGMENT 3 ................... 202
FIGURE 9.35.4.5.3-2. SAMPLE PSD PLOT FOR SEGMENT 3 ................................. 203
FIGURE 9.35.5.4-1. PSD CONNECTION DIAGRAM FOR SEGMENT 4 ................... 204
FIGURE 9.35.5.4-2. SAMPLE PSD PLOT FOR SEGMENT 4 .................................... 205
FIGURE 9.36.5-1. LOV TEST FIXTURE & CONNECTION DIAGRAM ...................... 208
FIGURE 9.36.5-2. SAMPLE LOV PLOT ..................................................................... 209
Figure 9.37-1. Voiceband Signal Power - Non-approved external signal sources
.............................................................................................................................. 214
Figure 9.38-1. Voiceband Signal Power - Non-approved external signal sources
.............................................................................................................................. 218
Figure 10.1-1 Transverse Balance, Analog ............................................................ 224
Figure 10.2-1 Transverse Balance, Digital ............................................................. 229
Figure 11.1-1. DC Resistance, T-R ......................................................................... 233
Figure 11.1-2. DC Resistance, T-GND & R-GND ................................................... 234
Figure 11.2-1. DC Current During Ringing ............................................................ 237
Figure 11.3-1. AC Impedance, T-R ......................................................................... 241
Figure 11.3-2. AC Impedance, T-GND & R-GND .................................................... 242
Figure 11.5-1. OPS Ring Trip .................................................................................. 247
Figure 11.7-1. Manual Programming of Repertory Dialing Numbers .................. 251
Figure 12.1-1. Call Duration, PC, Transmit ............................................................. 257
Figure 12.1-2. Call Duration, PC, Receive .............................................................. 258
Figure 12.2-1. Call Duration, EUT, Transmit ........................................................... 261
Figure 12.2-2. Call Duration, EUT, Receive ............................................................ 262
Figure 12.3-1. On-hook Signal Power, TE .............................................................. 265
Figure 12.3-2. On-hook Signal Power, PC .............................................................. 266
Figure 12.4-1. Loop Current, 200 ohm Method ...................................................... 270
Figure 12.4-2. Loop Current, 25% Method .............................................................. 271
Figure 12.5-1. Signaling Interference....................................................................... 275
Figure 12.7-1. Subrate and 1.544 Mb/s, On-hook Level......................................... 282
Figure 12.8-1. 1.544 Mb/s, Signaling Duration ....................................................... 285
Figure 12.9.5.1-1. Analog Direct Inward Dialing..................................................... 288
Figure 12.9.5.2-1 1.544 Mb/s Direct Inward Dialing................................................. 289
Figure 13.2-1 Nongold Contact Interface, Test Flow Chart ................................... 300
Figure 13.2-2. Contact Resistance Connections ................................................... 301
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Figure 14.1-1 Test Configuration to Establish Data Mode ..................................... 307
Figure 14.1-2 Test Configuration to Measure PSD and Total Power..................... 307
FIGURE 14.2-1 LOV TEST FIXTURE & CONNECTION DIAGRAM ......................... 311
Figure 15.1-1 Setup for testing FCC Part 68.316 HAC for Analog Telephone .... 318
Figure 15.1-2 Setup for testing FCC Part 68.316 HAC for ISDN Telephone ........ 319
Figure 15.1-3 Setup for testing FCC Part 68.316 HAC for Proprietary & Special
use Telephone ..................................................................................................... 320
Figure 15.1-4 Setup for testing FCC Part 68.316 HAC for IP-based Telephone . 321
Figure 15.2-1 Setup for testing FCC Part 68.317 HAC volume control for Analog
Telephone ............................................................................................................ 326
Figure 15.2-2 Setup for testing FCC Part 68.317 HAC volume control for ISDN
Telephone ............................................................................................................ 327
Figure 15.2-3 Setup for testing FCC Part 68.317 HAC volume control for
Proprietary & Special use Telephone ................................................................ 328
Figure 15.2-4 Setup for testing FCC Part 68.317 HAC volume control for IP-based
Telephone ............................................................................................................ 329
Figure 16.1-1 .............................................................................................................. 333
Figure A1-1. Subrate, Pulse Template, 2.4 kb/s ..................................................... 360
Figure A1-2. Subrate, Pulse Template, 3.2 kb/s ..................................................... 361
Figure A1-3. Subrate, Pulse Template, 4.8 kb/s ..................................................... 362
Figure A1-4. Subrate, Pulse Template, 6.4 kb/s ..................................................... 363
Figure A1-5. Subrate, Pulse Template, 9.6 kb/s ..................................................... 364
Figure A1-6. Subrate, Pulse Template, 12.8 kb/s ................................................... 365
Figure A1-7. Subrate, Pulse Template, 19.2 kb/s ................................................... 366
Figure A1-8. Subrate, Pulse Template, 25.6 kb/s ................................................... 367
Figure A1-9. Subrate, Pulse Template, 38.4 kb/s ................................................... 368
Figure A1-10. Subrate, Pulse Template, 51.2 kb/s ................................................. 369
Figure A1-11. Subrate, Pulse Template, 56.0 kb/s ................................................. 370
Figure A1-12. Subrate, Pulse Template, 72.0 kb/s ................................................. 371
Figure A1-13. PSDS Type II Pulse Template, 144 kb/s ......................................... 372
Figure A1-14. PSDS Type Iii Pulse Template, 160 kb/s ......................................... 373
Figure A2-1. 1.544 Mbps, Pulse Template, Option B .............................................. 375
Figure A2-2. 1.544 Mbps, Pulse Template, Option C .............................................. 376
Figure C1-1. Calculation of Energy Levels ............................................................. 379
Figure F-1: Test Fixture To Measure Transverse Balance Using A Ratio Of
Currents ............................................................................................................... 383
Figure F6-1. Chamber Zone Configuration ............................................................. 393
Figure F6-2. Control Coupon Locations ................................................................. 394
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1 INTRODUCTION
Part 68 of the Federal Communications Commission (FCC) rules and regulations (Ref
A17) contains and references the minimum technical standards that terminal equipment
must meet in order to be connected to the telephone network. 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. Part 68 defines harm as:




electrical hazards to the personnel of providers of wireline telecommunications;
damage to the equipment of providers of wireline telecommunications;
malfunction of the billing equipment of providers of wireline telecommunications;
and,
degradation of service to persons other than the user of the subject terminal
equipment and his calling or called party.
In addition, 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;
receive volume control on devices with a handset or headset;
identification of the sender of the message by telephone facsimile machines;
access to common carriers;
automatic dialing and redialing capability; and,
line seizure by automatic telephone dialing systems.
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 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 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 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 Part 68 and the technical
criteria adopted by the ACTA. At the time of publication, this TSB addressed
requirements in the following documents:
CFR, Title 47, Part 68
ANSI/TIA-968-A
ANSI/TIA-968-A-1 (addendum)
ANSI/TIA-968-A-2 (addendum)
T1.TRQ.6-2001
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 subsection of the applicable
requirements document. Section 4.5 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
NORMATIVE REFERENCES
13
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2. ANSI/EIA-364-13B-98 (1998), Mating and Unmating Forces Test Procedures for
Electrical Connectors.
15
16
3. ANSI/EIA-364-53B-00 (2000), Nitric Acid Vapor test, Gold Finish Test Procedure for
Electrical Connectors.
17
18
19
4. ANSI/TIA-968-A (2002), Telecommunications – Telephone Terminal Equipment Technical Requirements for Connection of Terminal Equipment to the Telephone
Network
20
21
5. ASTM B568-98 (1998), Standard Test Method for Measurement of Coating Thickness
by X-Ray Spectrometry.
22
23
6. ASTM B735-95 (2000), Standard Test Method for Porosity in Gold Coatings on Metal
Substrates by Nitric Acid Vapor
24
25
7. ASTM B741-95 (2000), Standard Test Method for Porosity In Gold Coatings On Metal
Substrates By Paper Electrography.
26
27
8. ATSM E384-99e1 (1999), Standard Test Method for Microindentation Hardness of
Materials
28
29
9. FCC Part 68, Code of Federal Regulations (CFR), Title 47, Part 68, Connection of
Terminal Equipment to the Telephone Network.
30
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10. FCC Public Notice 9160 (November 1, 1978), Notice of Declaratory Ruling on the
Interpretation of Section 68.314(d)
32
33
11. IEEE 1027 (1996), Method for Measuring of the Magnetic Field Intensity In The Vicinity
of a Telephone Receiver.
34
35
12. T1.TRQ.6-2001, Technical Requirements for SHDSL, HDSL2, HDSL4 Digital
Subscriber Line Terminal Equipment to Prevent Harm to the Telephone Network
36
37
38
13. TIA-504-A (1997), Telecommunications-Telephone Terminal Equipment-Magnetic
Field and Acoustic Gain Requirements for Headset Telephones Intended for Use by
the Hard of Hearing.
The following documents contain provisions that, through reference in this text,
constitute provisions of 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/EIA-364-09C-99 (1999), TP-09C, Durability Test Procedure for Electrical
Connectors and Contacts
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DEFINITIONS, ACRONYMS AND ABBREVIATIONS
These definitions are meant to be used within the framework of this document.
Additional definitions and information may be found in the publications referenced in
Appendix B.
 Cadenced Ringing
8
9
10
11
The process of alerting the called party with the application of a ringing signal which is
cycled on and off. Typical CO ringing consists of 2-second intervals of 20 Hz energy
applied between tip and ring, followed by a 4-second quiet interval. This sequence is
repeated until the called party answers or the call is abandoned.
12

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15
16
17
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”.
18

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21
22
23
24
A telephone executing coin acceptance requiring coin service signaling from the central
office on a loop-start access line. For Part 68 and TIA-968-A testing purposes, centraloffice-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 coinimplemented telephone.
25

26
Telephone Central Office.
27

28
29
30
31
32
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. For Part 68 and 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.
33

34
See Longitudinal Mode.
35

36
Equipment which is located on the customer's side of the network interface.
37

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A dc voltage or current.
Capture Level
Central-office-implemented telephone
CO
Coin-implemented telephone:
Common Mode
CPE - Customer Premises Equipment
DC Signal
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The transmission of information using changes in dc signals. Pulse dialing is an
example of dc signaling used for the purpose of network addressing.
4

5
6
Power level in decibels with reference to a power of 0.001 W (e.g., 0 dBm is a power
level of 1 mW).
7

8
9
Voltage in decibels with reference to a voltage level of 1 V (e.g. 0 dBV is a voltage level
of 1 V).
DC Signaling
dBm
dBV
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
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12
A feature that permits incoming PSTN calls to be routed directly to a PBX station upon
receipt of addressing information.
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
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See Metallic Mode.
15

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18
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 #).
19

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21
The digital representation of analog signals encoded in a digital bitstream. See also
Section 13.10.1.
22

EUT - Equipment Under Test.
23

FIC - Facility Interface Code
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25
A code which identifies the type of network facility necessary for a connection. These
codes are listed in the "Part 68 Application Guide"(Ref A17).
26

27
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A method of signaling whereby one of the network connections is grounded by
equipment (CO or CPE) originating a demand for service.
29

30
31
Any electrical path which, by design, has components which are intended to allow
currents to flow to ground.
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
ISDN - Integrated Services Digital Network
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
ISDN BRA - Basic Rate Access
34

ISDN Basic Rate Interface
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A two-wire interface between the terminal equipment and ISDN BRA.
DID - Direct Inward Dialing
Differential Mode
DTMF - Dual Tone Multi-Frequency
Encoded Analog Content
Ground Start
Intentional Conducting Path to Ground
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ISDN PRA - Primary Rate Access
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ISDN Primary Rate Interface
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A four-wire interface between the terminal equipment and 1.544 Mbps PRA.
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A pulse whose waveform is unaffected by leading or trailing pulses.
6

KTS - Key Telephone System
7

LADC - Local Area Data Channel
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9
A channel which allows wider than voiceband frequency transmission over network
private line metallic facilities.
Isolated Pulse
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
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Actual human speech as opposed to recorded or synthesized speech.
12

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14
That portion of a signal, which is identical in amplitude and phase, on both leads of a
transmission pair with respect to ground.
15

16
A method of signaling using the completion of a dc current path (loop).
17

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19
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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
21
A term used to denote the active state of telephone terminal equipment.
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
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A term used to denote the inactive state of telephone terminal equipment.
Live Voice
Longitudinal Mode
Loop Start
Metallic Mode
Off-Hook
On-Hook
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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.
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
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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.
OPS - Off Premises Station
Overload Point
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11
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.
12

PC - Protective Circuitry.
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
Primary Protector
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Devices, installed by the telephone companies, on circuits which are exposed to
voltages induced on cables by lightning strikes. Such devices limit the magnitude of the
voltage presented to the customer premises wire and equipment.
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
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A circuit simulating the netwrok side of the two-wire telephone connection that is used
for testing terminal equipment to be connected to the PSDS Type II loops.
20

PSTN - Public Switched Telephone Network.
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
Public Switched Digital Service Type I (PSDS Type I)
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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.
24

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28
This service functions in two modes, analog and digital. Analog signaling procedures
are used to perform supervisory and address signaling over the network. After an end
to end connection is established, the Switched Circuit Data Service Unit (SCDSU) is
switched to the digital mode.
29

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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.
PSDS Type II Analog Mode Loop Simulator Circuit
Public Switched Digital Service Type II (PSDS Type II)
Public Switched Digital Service Type III (PSDS Type III)
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A normalized measure of the on-hook electrical impedance load presented to the PSTN
by the CPE and 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).
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REN - Ringer Equivalence Number
Reverse Battery Interface
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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.
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
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SF is a method of network signaling that uses in-band signals. The SF signaling band is
from 2450 Hz to 2750 Hz. The SF guard band is from 800 Hz to 2450 Hz.
14

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A digital service providing full-time, simultaneous, two-way transmission of digital
signals at speeds as specified in Section 68.308
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
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A CPE device, with PSDS functionality, located between the network Interface and the
data terminal equipment. It is also sometimes referred to as Network Channel
Terminating Equipment).
21

22
23
A term that refers to that component of the telephone terminal equipment controlling its
operating states (See also On-Hook and Off-Hook).
24

TE - Terminal Equipment.
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
Test Equipment
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Equipment connected at the customer’s premises that is used on the customer’s side of
the network interfaces:
28
(a) to measure characteristics of the telephone network or;
29
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(b) to detect and isolate a communications fault between a terminal equipment entity
and the telephone network.
SF - Single Frequency
Subrate Digital Service
Switched Circuit Data Service Unit (SCDSU)
Switchhook
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A private line between two customer premises switching systems.
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
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Noise, either random or impulsive type, that has a flat frequency spectrum over the
frequency range of interest.
6

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8
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).
9

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11
Tie Trunk
White Noise
Zero Level Decoder
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.
11
12
13
14
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Each test procedure is cross-referenced to the appropriate subsection of the applicable
requirements document. Section 4.5 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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5.3
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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 Section 1 of 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 TIA968-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 TIA-968-A present to the CPEIf alternative loop simulators are used they
should be described in the test report.
The simulators specified in TIA –968-A are for compliance testing only. They are not
intended to ensure proper operation of the equipment when connected to the PSTN.
5.4
Test Conditions
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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)
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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 Section 68.3.
(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,
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.
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(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
(31)
(32)
(33)
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.
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.
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.
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.
Companion terminal equipment.
Concrete surface covered with 3mm of asphalt tile.
Current Source: Maximum Output: 1 A.
Data generator: output sequence random, maximum data rate >72 kb/s, output to
match data interface.
DC current meter: range 0 mA to 200 mA, accuracy +3% fsc.
DC current meter: range 20 uA, accuracy +3% fsc.
DC power supply: output level 0 V to 200 V, maximum output current >1A.
DC Voltmeter: input impedance >1 megohm, range 0 V to 200 V, accuracy
+3%
fsc.
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%.
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%.
DS1 transmission test set capable of sending a programmed bit stream.
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.
Frequency generator: output impedance 600 ohms, frequency range up to at least
4 kHz, maximum output level >40 dBm, sinusoidal output.
Frequency selective voltmeter: frequency range from 200 Hz to at least 4 kHz,
input impedance >10 kilohms, balanced input, range 1 uV to 1 V, accuracy +3%,
bandwidth 10 Hz and 30 Hz.
Hearing aid probe coil assembly: see Section 68.316.
Transverse balance bridge: See Figure 68.310(a) and Note (3) of this section.
Means to record oscilloscope and spectrum analyzer traces.
Multiplexer/demultiplexer for 1.544 Mb/s PCM systems with zero level
encoder/decoder, may consist of one or more discrete units which perform this
function.
Ringing Amplifier: Output level to at least 150 Vrms superimposed on 56.5 Vdc,
frequency range 15.3 Hz to 68 Hz.
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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.
Summing Network: input and output impedances 600 ohms.
Type A Surge generator: output 800 V peak, having 10 s maximum front time to
crest and a 560 s 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.
Type A Surge generator: output 1500 V peak, having 10 s maximum front time to
crest and a 160 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.
Surge generator: output 2500 V peak, having 2 s maximum front time to crest
and a 10 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.
Tracking generator: output impedance <600 ohms, frequency range from 10 Hz to
at least 6 MHz, maximum output level 0 dBm.
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%.
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%.
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).
Voltage source: output 120 Vrms at 60 Hz, output current 10 mA.
Voltage source: output 300 Vrms at 60 Hz, output current 10 mA.
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.
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.
Type B Metallic Surge Generator: 1000 V minimum peak open circuit voltage at
the output port, with a 9 s front time, ±30%, and a 720 s decay time, ±20%; 25A
minimum peak short circuit current at the output port, with a 5 s front time, ±30%,
and a 320 s decay time, ±20%. The generator must be able to generate these
pulses in either polarity.
Type B Longitudinal Surge Generator: 1500 V minimum peak open circuit voltage
at each output port simultaneously, with a 9 s front time, ±30%, and a 720 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 must be able to generate these pulses in either polarity.
Feeding Bridge with 2 F blocking capacitors and inductors of 1.8 Henries
minimum at 200 Hz for analog
telephone.
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(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 artificial ear is to be the IEC coupler for supra-aural earphones as
described in ANSI S3.7-1973, 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.
(52) Standard microphone: A type (0.5 in) laboratory standard pressure microphone
according to ANSI S1.12-1967[3] 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 must 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.
(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  balun transformer: frequency range 10 kHz to 30 MHz minimum.
(60) 10 dB 50  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 1M ohms, 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  balun transformer: frequency range 1 kHz to 10 MHz minimum.
(65) 135:50  balun transformer: frequency range 20 Hz to 2 MHz minimum.
(66) 135:50  balun transformer: frequency range 5 MHz to 30 MHz minimum.
(67) Artificial line: 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
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(b)
(c)
(d)
(e)
satisfactory for most tests.
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.
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.
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.
NOTES:
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.
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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 9.21.
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Note 4.
The specialized test equipment used in Section 15 is not itemized here.
Refer to Section 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 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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Editor’s note: The old matrix will be replaced with a new one, based on the matrix in
TR41.9.2-03-11-029
Test Requirements Matrix
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6.1
ENVIRONMENTAL SIMULATION TIA-968-A Par 4.2
Sequencing of Environmental Simulations
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TIA-968-A Par 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 Par 4.2, 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 nonserially.
Circumstances may occasionally require parallel testing of the equipment. In this case,
one unit is subjected to the environmental stresses of Par 4.2 while a second unit is
maintained in a non-stressed condition. The two units are then examined for
compliance to the requirements of TIA-968-A Par 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 Equipment Under Test (EUT) may be considered compliant when all applicable
pre- and post-environmentally obtained data meets Part 68 and TIA-968-Arequirements.
If environmental stresses impair the function of the EUT, good engineering judgment
must 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 to adequately profile the
EUT’s post-environmental condition.
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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
EUT must be fully functional before beginning the initial electrical tests. 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 Part 68 /TIA-968-Arequirements 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:
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(Example: Data modem will not transmit data.)
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“Operational failure” means the device will not function normally or as
intended. Measurement may or may not be necessary.
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Such a condition does not mean failure of Part 68/ TIA-968-A. This can
only be determined by completing all applicable tests on the equipment
and verifying compliance with Part 68/ 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 FCC Part 68 and 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 must
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be exercised in determining which Part 68 / TIA-968-A requirements
remain applicable, and what comparison post-environmental data is
required (and what techniques must be employed in acquiring such data).
Note 6.
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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 "Part 68 Application Guide" ( Ref A17) TIA/TSB129A ”Telecommunications - Telephone Terminal Equipment - Guide to
the U.S. Supplier's Declaration of Conformity and TCB Approval
Processes”
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6.2
Mechanical Shock TIA-968-A Par 4.2.1
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6.2.1 Background
Terminal equipment may be subjected to mechanical shock during shipping, installation,
and use. This shock may damage or misposition 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
To simulate handling of terminal equipment during installation and use.
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(a)
(1)
Concrete surface SEL#16.
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NOTE: Refer to Section 5.3 for equipment details.
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6.2.4 Equipment States Subject To Test
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Unpackaged and unpowered.
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6.2.5 Procedure
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Refer to TIA-968-A Par 4.2.1 for procedure and equipment weight classification.
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6.2.6 Alternative Methods
None.
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6.2.7 Suggested Test Data
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(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.
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6.3
Telephone Line Surge - Type A, Metallic. TIA-968-A Par 4.2.2.1
6.3.1 Background
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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.
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6.3.2 Purpose
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To simulate induced metallic surge voltages on a telephone line which could result from
lightning.
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6.3.3 Equipment
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(1)
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Surge Generator SEL# 36.
NOTE: Refer to Section 5.3 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
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WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
(1)
Refer to TIA-968-A Par 4.2.1.1.1 for the connections to be surged.
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(2)
Place the equipment in the state to be tested.
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(3)
Apply a surge of each polarity.
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(4)
Check EUT operation and record the results.
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(5)
Change states as necessary and repeat Step (2) through Step (4).
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6.3.6 Alternative Methods
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None.
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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 TIA-968-A Par 4.2.2.3 for discussion.
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Telephone Line Surge - Type A, Longitudinal. TIA-968-A Par 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.
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6.4.2 Purpose
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6.4.3 Equipment
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6.4.4 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.
To simulate longitudinal surge voltages which could result due to lightning strikes on the
telephone line.
Surge generator SEL# 37.
NOTE: Refer to Section 5.3 for equipment details.
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WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
Refer to TIA-968-A Par 4.2.2.2.1 for the connections to be surged.
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(1)
Place the EUT in the state to be tested.
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(2)
Apply a surge of each polarity.
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(3)
Check EUT operation and record the results.
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(4)
Change states as necessary and repeat Step (3) and Step (4).
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6.4.6 Alternative Methods
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6.4.7 Suggested Test Data
(1)
Equipment state(s).
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(2)
Leads tested.
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(3)
Observed Results.
None.
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6.4.8 Comments
(1)
Terminate EUT leads not being surged in a manner which is no less severe than
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 TIA-968-A Par 4.2.2.3 for discussion.
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Telephone Line Surge - Type B, Metallic. TIA-968-A Par 4.2.3.1
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6.5.1 Background
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6.5.2 Purpose
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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 TIA-968-A Par
4.2.3 simultate 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.
Surge Generator SEL# 47.
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NOTE: Refer to Section 5.3 for equipment details.
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6.5.4 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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6.5.5 Procedures
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
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Refer to TIA-968-A Par 4.2.3.1 for the connections to be surged.
2
3
(1)
Place the equipment in the state to be tested.
4
(2)
Apply a surge of each polarity.
5
(3)
Check EUT operation and record the results.
6
(4)
Change states as necessary and repeat Step (2) through Step (4).
7
8
6.5.6 Alternative Methods
None.
9
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6.5.7 Suggested Test Data
11
(1)
Equipment state(s).
12
(2)
Leads tested.
13
(3)
Observed Results.
14
15
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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.
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19
(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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21
(3)
The EUT must comply with the failure criteria outlined in TIA-968-A Par 4.2.3.3 after
surge.
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(4)
The surge generator waveform parameters specified are based on an analysis of the
surge generator circuit of ITU (formerly CCITT) Recommendation K.21. This
recommendation specifies a nominal open circuit voltage waveform of 10 s x
700 s. Commercial surge generators are generally built to the ITU
Recommendation and the 10 s x 700 s waveform provided is within the tolerances
of the 9 s x 720 s open circuit waveform specified in TIA-968-A Par 4.2.2.1.2 –
4.2.2.2.2. Surge generators conforming to the ITU Recommendation also meet TIA968-A Par 4.2.2.1.2 – 4.2.2.2.2.
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(5)
For Type B surges, the equipment must be capable of withstanding the energy of
these surges without causing permanent opening or shorting of the interface circuit
and without sustaining other damages
that will affect compliance. It is not
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2
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4
required to be fully operational, but any failure must be non-harmful. 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.
5
6
7
8
(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.
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10
(7)
The EUT is not to open the interface circuit by opening a trace, fuse, or component in
the interface circuit.
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6.6
Telephone Line Surge - Type B, Longitudinal. TIA-968-A Par 4.2.3.2
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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
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6.6.2 Purpose
11
12
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6.6.3 Equipment
To simulate low energy longitudinal surge voltages induced by lightning.
Surge generator SEL# 48
14
15
NOTE: Refer to Section 5.3 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
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24
6.6.5 Procedure
25
(1)
Place the EUT in the state to be tested.
26
(2)
Apply a surge of each polarity.
27
(3)
Check EUT operation and record the results.
28
(4)
Change states as necessary and repeat step (3) and step (4).
29
30
31
6.6.6 Alternative Methods
WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
Refer to TIA-968-A Par 4.2.2.2.1 for the connections to be surged.
None.
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6.6.7 Suggested Test Data
(1)
Equipment state(s).
4
(2)
Leads tested.
5
(3)
Observed Results.
6
7
8
9
6.6.8 Comments
(1)
Terminate EUT leads not being surged in a manner which is no less severe than
occurs in normal use.
10
11
(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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13
(3)
The EUT must comply with the failure criteria outlined in TIA-968-A Par 4.2.2.3 after
surge.
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19
20
21
(4)
The surge generator waveform parameters specified are based on an analysis of the
surge generator circuit of ITU (formerly CCITT) Recommendation K.21. This
recommendation specifies a nominal open circuit voltage waveform of 10 s x
700 s. Commercial surge generators are generally built to the ITU
Recommendation and the 10 s x 700 s waveform provided is within the tolerances
of the 9 s x 720 s open circuit waveform specified in TIA-968-A Par 4.2.2.1.2 –
4.2.2.2.2. Surge generators conforming to the ITU Recommendation also meet TIA968-A Par 4.2.2.1.2 – 4.2.2.2.2.
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(5)
For Type B surges, the equipment must be capable of withstanding the energy of
these surges without causing permanent opening or shorting of the interface circuit
and without sustaining other damages that will affect compliance. It is not required to
be fully operational, but any failure must be non-harmful. 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.
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(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.
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(7)
The EUT is not to open the interface circuit by opening a trace, fuse, or component in
the interface circuit.
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6.7
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6.7.1 Background
7
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6.7.2 Purpose
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Power Line Surge TIA-968-A Par 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
Surge generator SEL# 38.
13
14
NOTE: Refer to Section 5.3 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 TIA-968-A Par 4.2.4.1 for the connections to be surged.
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6.7.6 Alternative Methods
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6.7.7 Suggested Test Data
None.
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(1)
Voltage.
2
(2)
Equipment state(s).
3
(3)
Number of surges and polarity.
4
(4)
Observed results.
5
6
7
6.7.8 Comments
8
9
(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.
10
11
(2)
The EUT is permitted to reach certain failure modes after application of these surges.
See TIA-968-A Par 4.2.4.2 for discussion.
12
13
(3)
The test arrangement must be configured to apply the surge to the EUT without
affecting, or being affected by, the ac power line.
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15
16
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7
LEAKAGE CURRENT LIMITATIONS (ANALOG AND DIGITAL) TIA-968 Par 4.3
40
41
7.4 Equipment States Subject to Test
42
43
44
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
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 Section 5.3 for equipment details.
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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, but the method used must 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 offhook mode. For the EUT-to-power-line barrier test (1500 V), the EUT is not powered
but the power switch must be in the ON position 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 Section 68.304.
7.6 Alternative Methods
The 1500 VAC test may be conducted using a DC equivalent of 2121 VDC.
39
40
41
42
43
7.7 Suggested Test Data
44
Voltage applied (V rms).
Identify electrical connections or test points.
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2
3
4
5
Maximum current (mA peak).
7.8 Comments
(1)
Leads may be tested as a group or as indicated in Section 68.304.
(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.
13
14
(3)
As shown in the test setup, the leakage current is equal to the voltage measured
across the 1000-ohm resistor divided by 1000.
15
(4)
There are three intentional paths to ground considered:
6
7
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9
10
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12
16
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21
22
(a)
23
24
25
26
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(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 Section 68.306(e)(2).
Typically, a suppressor is rated at greater than 130 V to be transparent to
ringing voltages.
30
31
32
33
34
(c)
Filter paths on the interface circuit are left in place during testing. Filter
components must withstand 1000 V, which provides the capability to
withstand surges. These paths are identified as not conductive for DC. To
pass a 1000 V test, a capacitor needs about a 400 WVDC rating. These are
special capacitors, designated “X-capacitors”, or “Y-capacitors”.
35
36
37
38
39
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 Section 68.306(e)(1). 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.
(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
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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 68.306(e)(1) referred to in section
7.4.1 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).
12
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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.
NOTES:
1. A 1500 V ac voltmeter or a resistive voltage divider and high impedance voltmeter may
be used.
2. The 50-kilohm current-limiting resistor is optional but is recommended to reduce the
possibility of damage in case of insulation breakdown.
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.
Figure 7-1. Leakage Current
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8.1
HAZARDOUS VOLTAGE LIMITATIONS 68.306 TIA-968-A Par 4.4
Hazardous Voltage Limitations, General TIA-968-A Par 4.4.1
4
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8.1.1 Background
12
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8.1.2 Purpose
16
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18
8.1.3 Equipment
19
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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 nomal 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.
32
(3)
Repeat steps (1)(a) through (d).
33
(4)
Connect the oscilloscope leads from ring to ground.
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(5)
Repeat steps (1)(a) through (d).
2
3
4
8.1.6 Alternative Method
5
6
7
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9
8.1.7 Suggested Test Data
None suggested.
For Tip - Ring, Tip - Ground, and Ring - Ground:
(1)
Maximum peak ac voltage measured if less than 70 volts peak.
10
(2)
Maximum and duration if peak ac voltage is greater than 70 volts..
11
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13
8.1.8 Comments
None.
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8.2
Hazardous Voltage Limitations, E&M TIA-968-A Pars 4.4.1.1, 4.4.1.2, 4.4.1.3
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8.2.1 Background
19
20
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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
33
34
35
36
37
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).
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 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 Section 5.3 for equipment details.
8.2.4 Equipment States Subject to Test
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
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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.
8.2.5 Procedure
Unless otherwise specified below, all tests should be made in the idle state.
Lead designations are the same as in Section 4.4.1.1 and Section 4.4.1.3 of 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:
(1)
14
DC current to ground.
Ground the lead through the current meter, and measure the resulting current.
15
16
(2)
17
18
AC voltage to ground.
Connect ac voltmeter between designated lead and ground, and measure the
voltage.
19
20
(3)
21
22
DC voltage to ground.
Connect dc voltmeter across a 20 kOhm +/-10% resistor located between
designated lead and ground, and measure the voltage.
23
24
(4)
25
26
27
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.
28
29
30
NOTE: This is provided by Surge Suppression (SS) in Figure 1.5 of TIA-968-A. See
Comment (1).
31
32
(5)
Contact Protection.
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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,
7
2. the rate of change of voltage to 1 V/s, and
8
3. the voltage level to 60 V or less after 10 ms (See Comment (2)).
9
10
(6)
Voltage measurements
11
1. Connect the EUT to the test circuit of Figure 8.2-1.
12
2. Open switch S1 and record the oscilloscope trace.
13
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
30
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8.2.8 Comments
(1)
Where compliance is verified by inspection, include a short discussion describing the
means provided.
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 100043
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ohm 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.
(2)
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 
10
11
12
13
14
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16
L
where:
C is the capacitance in 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 V/s is satisfied when:
 F
C F  I A  1

 A
17
18
19
20
21
2
Other methods of transient suppression for inductive loads include placing a diode
in series with a zener diode or a varistor across the inductor.
(3)
Refer to section 4.4.3 for the definition of non-hazardous voltage.
22
23
24
TABLE 8.2-1
E&M LEADS TO BE TESTED
25
Interface Type
Side of the Interface
Lead to be Tested
1
2
3
4
5
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
Contact Protection X
26
27
44
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
X
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
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 TIA-968-A, 4.4.1.4
2
3
4
5
6
7
8
9
10
11
12
13
8.3.1 Background
14
15
16
8.3.2 Purpose
17
18
19
8.3.3 Equipment
(1)
DC voltmeter SEL# 22.
20
(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.
21
22
NOTE: Refer to Section 5.3 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
8.3.5 Procedure
(1)
In the idle open circuit state, measure the dc voltage with the dc voltmeter connected between:
30
(a)
T(OPS) and R(OPS);
31
(b)
T(OPS) and ground;
32
(c)
R(OPS) and ground.
33
34
(2)
In the idle open circuit state, measure the extraneous ac voltage with the ac voltmeter connected
between:
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(a)
T(OPS) and R(OPS);
2
(b)
T(OPS) and ground;
3
(c)
R(OPS) and ground.
4
5
(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:
6
(a)
T(OPS) and ground;
7
(b)
R(OPS) and ground.
8
(4)
Perform tests specified in Section 8.8 to verify compliance with ringing source requirements.
9
10
11
8.3.6 Alternative Methods
12
13
14
8.3.7 Suggested Test Data
None suggested.
(1)
DC voltages during idle open circuit state:
15
(a)
T(OPS) and R(OPS);
16
(b)
T(OPS) and ground;
17
18
19
(c)
R(OPS) and ground
(2)
Extraneous ac voltages during idle open circuit state:
20
(a)
T(OPS) and R(OPS);
21
(b)
T(OPS) and ground;
22
(c)
R(OPS) and ground.
23
(3)
Ringing ac voltages during ringing open circuit state:
24
(a)
T(OPS) and ground;
25
(b)
R(OPS) and ground.
26
(4)
Verification of proper application of ringing.
27
(5)
Test data as specified in Section 8.8.7.
28
29
30
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
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2
3
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.
4
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2
8.4
Hazardous Voltage Limitations, DID TIA-968-A Par 4.4.1.5
3
4
5
6
7
8
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 Section 5.3 for equipment details.
17
18
19
8.4.4 Equipment States Subject to Test
20
21
22
23
8.4.5 Procedure
IIdle 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
28
29
(2)
In the idle open circuit state, measure the extraneous ac voltage with the ac
voltmeter connected between:
30
(a)
T and R;
31
(b)
T and ground;
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(c)
R and ground.
2
3
4
8.4.6 Alternative Methods
5
6
7
8.4.7 Suggested Test Data
None suggested.
(1)
DC voltages during idle open circuit state:
8
(a)
T and R;
9
(b)
T and ground;
10
(c)
R and ground.
11
12
(2)
Extraneous ac voltages during idle open circuit state:
13
(a)
T and R;
14
(b)
T and ground;
15
(c)
R and ground.
16
17
18
8.4.8 Comments
Refer to 68.306(c) for the definition of non-hazardous voltage.
19
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8.5
Hazardous Voltage Limitations, LADC TIA-968-A Par 4.4.1.6
2
3
4
5
6
7
8
9
10
11
8.5.1 Background
12
13
14
15
8.5.2 Purpose
16
17
18
8.5.3 Equipment
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
Section 68.306(c). If ringing is used, it is to meet the requirements of Section 68.306(d)
(see Section 7.7 for test procedures).
To verify that the currents and voltages present at the interface are not hazardous to
personnel or equipment.
(a)
DC voltmeter SEL# 22.
19
(b)
Digital sampling storage oscilloscope SEL# 23.
20
(c)
True rms current meter SEL# 42.
21
NOTE: Refer to Section 5.3 for equipment details.
22
23
8.5.4 Equipment States Subject to Test
All operating states, except ringing.
24
25
26
27
28
29
8.5.5 Procedure
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
(1)
Place EUT in first operating state.
30
31
(2)
Connect current meter between T and R leads of the EUT, and measure combined
ac and dc short circuit current.
32
33
(3)
Repeat Step (2) with current meter between T and ground and between R and
ground.
34
(4)
Repeat Step (1) through Step (3) for the T1 and R1 pair of the EUT if testing a four-
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wire interface.
2
(5)
Connect dc voltmeter between T and ground, and measure voltage.
3
(6)
Repeat Step (5) with voltmeter between R and ground.
4
(7)
Repeat Step (5) and Step (6) for the T1 and R1 pair if testing a four-wire interface.
5
6
(8)
Connect oscilloscope between T lead and ground, and measure ac peak and
combined ac peak and dc voltages with other network leads unterminated.
7
(9)
Repeat Step (8) with oscilloscope between R and ground.
8
(10)
Repeat Step (8) and Step (9) for the T1 and R1 pair if testing a four-wire interface.
9
10
(11)
Repeat Step (8) through Step (10) for ac peak voltage only with other network leads
individually terminated to ground.
11
(12)
Repeat Step (2) through Step (11) for other modes of operation.
12
13
14
8.5.6 Alternative Methods
15
16
17
8.5.7 Suggested Test Data
(1)
Current between conductor pairs (ac and dc).
18
(2)
Current between each conductor and ground (ac and dc).
19
(3)
DC voltages to ground for each conductor.
20
(4)
AC voltages to ground for each conductor (other conductors unterminated).
21
(5)
AC voltages to ground for each conductor (other conductors terminated).
22
23
(6)
AC plus dc (total) voltages to ground for each conductor (other conductors
unterminated).
24
25
26
27
8.5.8 Comments
None suggested.
Refer to 68.306(c) for the definition of non-hazardous voltage.
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2
8.6
Ringdown Voiceband Private Line and Metallic Channel Interface
TIA-968-A Par 4.4.1.7
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
8.6.1 Background
18
19
20
21
8.6.2 Purpose
22
23
24
25
26
27
8.6.3 Equipment
28
29
30
8.6.4 Equipment States Subject to Test
(1)
Idle.
31
(2)
Talking.
32
(3)
Signaling.
33
34
35
36
37
38
8.6.5 Procedure
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 Section 7.7.1, 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.
DC current meter SEL# 19.
DC voltmeter SEL# 22.
NOTE: Refer to Section 5.3 for equipment details.
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
Inspect appropriate circuit diagrams to verify the following:
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2
3
(1)
Ringing voltage is applied to the R lead with the T lead grounded for two-wire
interfaces;
4
5
(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.
6
7
(3)
Perform tests specified in Section 7.7.5 to verify compliance with ringing source
requirements in the signaling state.
8
(4)
Place EUT in the idle state.
9
10
(5)
Connect dc voltmeter between T lead and ground of the EUT, and measure the
voltage, noting polarity.
11
(6)
Repeat Step (4) for R lead.
12
13
(7)
Repeat Step (4) and Step (5) for T1 and R1 leads of the EUT if testing a four-wire
interface.
14
(8)
Repeat Step (3) through Step (6) with EUT in the talking state.
15
(9)
Place EUT in idle state.
16
(10)
Connect current meter between T and R leads, and measure short circuit current.
17
(11)
Repeat Step (9) between T lead and ground and between R lead and ground.
18
(12)
Repeat Step (9) for T1 and R1 leads if testing a four-wire interface.
19
(13)
Repeat Step (9) through Step (11) for talking state.
20
21
22
23
8.6.6 Alternative Methods
24
25
26
27
28
29
30
8.6.7 Suggested Test Data
31
None suggested.
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:
(a)
T to ground;
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(b)
R to ground;
2
(c)
T1 to ground;
3
(d)
R1 to ground.
4
5
(2)
DC current during idle and talking states:
6
(a)
T to R;
7
(b)
T to ground;
8
(c)
R to ground;
9
(d)
T1 to R1;
10
(e)
T1 to ground;
11
(f)
R1 to ground.
12
13
14
15
8.6.8 Comments
Refer to 68.306(c) for the definition of non-hazardous voltage.
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2
3
4
5
6
7
8.7
Physical Separation of Leads TIA-968-A Paragraph 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).
16
17
NOTE: Refer to Section 5.3 for equipment details.
To verify that network interface leads are adequately separated from power leads and
from hazardous voltage leads that connect to non-approved equipment.
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
31
32
33
34
35
36
37
38
If voltage measurements are necessary, the EUT must be powered and connected to
non-approved equipment if it provides a source of hazardous voltage.
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
(1)
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 TIA-968-A Paragraph 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
adequately separated from power leads and from leads to non-approved equipment
carrying hazardous voltage as follows: Leads for connection to the network must not
be 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 must not be routed
in the same cable as or use adjacent pins on the same connector as leads to non–
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approved equipment where those leads carry hazardous voltage.
2
3
(3)
Use the ac or dc voltmeter as required to confirm that the affected leads to nonapproved equipment are indeed hazardous.
4
5
6
8.7.6 Alternative Methods
7
8
9
8.7.7 Suggested Test Data
None suggested.
(1)
Provide a short discussion that summarizes observation of:
10
(2)
Lead separations.
11
(3)
Voltages on leads to non-approved equipment.
12
(4)
Lead routing in cables.
13
14
(5)
Pin assignments in connectors with leads for connection to both the network
interface and non-approved equipment.
15
16
17
18
19
8.7.8 Comments
The identification of non-hazardous voltage leads to non-approved equipment may be
verified by inspecting the circuit diagram or actual measurement as appropriate.
20
21
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8.8
Ringing Sources TIA-968-A Par 4.4.4
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
8.8.1 Background
23
24
25
8.8.2 Purpose
26
27
28
8.8.3 Equipment
(1)
Digital sampling storage oscilloscope SEL# 23.
29
(2)
Frequency counter SEL# 26.
30
31
32
33
34
35
36
37
38
39
A ringing source is considered to be non-hazardous to telephone company personnel if
it meets the current, voltage, and duration requirements in Section 4.4.4 of TIA-968-A.
The requirements take into account wet hands-to-feet contact and wet hand-to-hand
contact. Current values up to 100 mA peak-to-peak are permitted for a period of 5 s
after which there must be a silent (no ringing) interval of at least 1 s 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 s, as
depicted in Figure 4.4 of 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 it must disconnect the ringing source 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-toground 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.
NOTE: Refer to Section 5.3 for equipment details.
8.8.4 Equipment States Subject to Test
There are two operating states: ringing and non-ringing. All measurements except for
monitoring voltage are made in the ringing state. Monitoring voltage, when required, is
measured in both states.
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2
3
4
5
6
7
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.
8
9
10
(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.
11
12
(3)
Connect the EUT to the test circuit of Figure 8.2-1 if the EUT is a two-wire device or
to the test circuit of Figure 8.2-2 if the EUT is a four-wire device.
13
14
15
16
NOTE: A 10X probe should be used.
(4)
Set switch S1 to position "A" and measure:
17
18
(a)
peak-to-peak ringing voltage;
19
(b)
peak-to-ground ringing voltage;
20
(c)
ringing time interval;
21
(d)
non-ringing time interval.
22
23
(5)
Set switch S1 to position "B" and initiate ringing.
24
(6)
Measure and record the peak-to-peak voltage.
25
(7)
If ringing is tripped, measure duration of applied ringing.
26
(8)
Convert the voltage recorded in Step (6) to peak-to-peak current in milliamperes.
27
(9)
Set switch S1 to position "C" and repeat Step (5) through Step (8).
28
29
(10)
Refer to the table in Figure 8.2-3 to determine compliance with ringing voltage and
the need for a tripping device and a monitoring voltage.
30
31
32
33
34
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
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and
non-ringing states.
2
3
4
8.8.6 Alternative Methods
5
6
7
8.8.7 Suggested Test Data
(1)
Ringing frequency.
8
(2)
Ringing voltages, peak-to-peak and peak-to-ground.
9
(3)
Duration of the ringing interval.
10
(4)
Duration of the non-ringing interval.
11
(5)
Current through 500-ohm resistance and trip time, if required.
12
(6)
Current through 1500-ohm resistance and trip time, if required.
13
(7)
Monitor voltage, if required.
14
15
16
8.8.8 Comments
None suggested.
Refer to TIA-968-A Section 4.4.3 for the definition of non-hazardous voltage.
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2
3
4
5
6
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 8.2-1 Ringing Sources, Two-Wire
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1
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 8.2-2 Ringing Sources, Four-Wire
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2
3
4
5
6
7
8
Figure 8.2-3 Ringing Protection
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8.9
Intentional Paths to Ground TIA-968-A Par 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 TIA-IS-968 4.3. To ensure that these network connections
do not pose a hazard to network personnel, a ground continuity test must be 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
To verify the ground continuity between grounded telecommunications points and EUT
earth grounding connections.
NOTE: Refer to Section 5.3 for equipment details.
30
31
32
33
34
35
36
8.9.4 Equipment States Subject to Test
37
38
8.9.5 Procedure
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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WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
(1)
Connect the EUT to the test circuit of Figure 8.4.1-1.
5
(2)
Select the appropriate EUT test points.
6
7
(3)
Gradually increase the current from zero to 1 A, then maintain the 1 A current for one
minute.
8
9
(4)
Monitor the voltage on the DC voltmeter. The voltage must not exceed 0.1 Volt at
any time.
10
11
12
8.9.6 Alternative Methods
13
14
15
8.9.7 Suggested Test Data
(1)
List of test points.
16
(2)
Maximum dc voltage measured during tests.
17
18
19
20
21
8.9.8 Comments
None suggested.
Refer to 68.306(c) for the definition of a non-hazardous voltage source and TIA-IS-968
4.3 Note (1).
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8
NOTE A - See 7.3.1.3
Figure 8.4.1-1 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
8.10.1 Background
4
5
6
7
8
9
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 Section 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 Section 5.3 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 Section 7).
30
(2)
Connect the EUT to the test circuit of Figure 8.10-1.
31
(3)
Select the appropriate EUT test points.
32
33
(4)
Gradually increase the voltage from zero to 120 VRMS (for TE) or 300 VRMS (for PC). Maintain the
maximum voltage for one minute.
34
(5)
Monitor the current through the AC ammeter. The current must not exceed 10 mA peak at any time.
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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2
3
8.10.6 Alternative Methods
4
5
6
8.10.7 Suggested Test Data
(1)
List of leads tested.
7
(2)
List of maximum current measured for each combination.
8
9
10
11
12
13
None suggested.
8.10.8 Comments
(1)
This test is to be applied to leads excluded from the requirements of ANSI/TIA-968-A, 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 section 8.9 of this document
14
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6
7
8
9
10
11
12
13
14
15
16
17
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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7
8
9
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29
30
31
32
33
34
35
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37
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9
SIGNAL POWER LIMITATIONS TIA-968, 4.5
9.1
Voiceband Signal Power – Not Network Control signals TIA-968, 4.5.2.1
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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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
16
NOTE: Refer to Section 5.3 for equipment details.
17
18
9.1.4 Equipment States Subject to Test
19
20
21
22
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 Section 8.4.
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.
31
(4)
Repeat step (2) and step (3) for other internal signals.
32
(5)
Repeat step (2) through step (4) for other operating states, if applicable.
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2
3
4
5
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.
6
(2)
Set the signal analyzer to measure the following:
7
(a)
Signal level in dBm, 600 ohms.
8
(b)
Averaging over 3 second.
9
(c)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
10
11
Note: If the Signal Analyzer does not provide a balanced input an isolation
transformer may be used.
12
13
(3)
Place the EUT in the desired off-hook state and transmit a desired signal from
internal sources at maximum power.
14
15
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
16
(5)
Repeat step (2) and step (3) for other internal signals.
17
(6)
Repeat step (2) through step (4) for other operating states, if applicable.
18
19
20
21
9.1.7 Suggested Test Data
(1)
Operating states.
22
(2)
Signals measured.
23
(3)
Signal power levels in dBm.
24
(4)
Loop conditions for maximum signal power if appropriate.
25
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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
(3)
As mentioned in Section 8.1.1, the level of live-voice signals are not regulated under
Part 68. Recorded or synthesized signals are not live-voice signals and, as such, are
regulated by Part 68. Typically there are three types of signals to consider:
10
11
12
13
14
15
(a)
16
17
18
19
20
21
22
(b)
23
24
(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).
25
26
27
28
29

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.
30
31
32
33

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).
34
35
36
The test signal used may depend on the EUT. Possible signals include, but are 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.
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4
(4)
A voltmeter with an averaging time less than 3 seconds may be used. In this case
correction factors must be applied to the measured value based on the duty cycle of
the signals.
5
(5)
The insertion loss of the bandpass filters used is to be taken into account.
6
7
(6)
The insertion loss of any balanced to unbalanced transformer used is to be taken into
account.
(1)
Select the appropriate loop simulator for the interface of the EUT.
12
13
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968.
14
15
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968.
8
9
10
11
16
17
18
Figure 9.1-1. Voiceband Signal Power, Two-Wire
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2
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4
5
(1)
Select the appropriate loop simulator for the interface of the EUT.
6
7
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968.
8
9
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968.
10
11
12
Figure 9.1-2. Voiceband Signal Power, Four-Wire
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8
9
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 TIA-968-A, 4.5.2.2
9.2.1 Background
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.
16
17
18
19
20
21
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
4.5.2.2 of TIA-968-A although they are not specifically mentioned by name.
22
23
24
25
9.2.2 Purpose
26
27
28
9.2.3 Equipment
(1)
Applicable loop simulator SEL# 4.
29
(2)
Bandpass filter SEL# 5.
30
(3)
DC current meter SEL# 19.
31
(4)
True rms ac voltmeter SEL# 40.
32
33
34
35
36
37
38
To verify that the level of any signal primarily intended for network control is properly
limited.
NOTE: Refer to Section 5.3 for equipment details.
9.2.4 Equipment States Subject to Test
Test any off-hook states of the EUT which transmit to the network signals primarily
intended for network control.
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9.2.5 Procedure
(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.
5
(2)
Set the voltmeter to measure the signal level in dBm.
6
(3)
Place the EUT in the off-hook state and transmit a desired network control signal.
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
7
8
9
10
11
(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).
12
(6)
13
14
15
16
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 XX).
17
(2)
Set the signal analyzer to measure the following:
Repeat step (3) and step (4) for other operating states, if applicable.
18
(d)
Signal level in dBm, 600 ohms.
19
(e)
Averaging over 3 second.
20
(f)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
21
22
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
23
24
(3)
Place the EUT in the desired off-hook state and transmit a desired Network Control
signal.
25
26
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
27
28
(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).
29
(5) Repeat step (2) through step (4) for other operating states, if applicable.
30
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9.2.7 Suggested Test Data
(1)
Operating states.
4
(2)
Network Control Signal.
5
(2)
Signal power levels in dBm.
6
(3)
Loop conditions for maximum signal power, if appropriate.
7
8
9
10
9.2.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
11
12
(2)
For EUT using manual DTMF signaling, the signal level shall be measured for each
digit and the one having the maximum power shall be reported.
13
14
(3)
For EUT using manual DTMF signaling, a duty cycle of 40% is assumed. Thus
reduce the measured level by 4dB.
15
16
(4)
For EUT using automatic DTMF signaling, the sequence of numbers should use all
digits and be of maximum address length.
17
(5)
No measurements are required for dc pulse dialing.
18
19
20
(6)
A voltmeter with an averaging time less than 3 seconds may be used. In this case
correction factors must be applied to the measured signal power based on the duty
cycle.
21
(7)
Insertion loss of bandpass filter shall be taken into account.
22
23
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4
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NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
6
7
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
8
9
(3)
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the figures of Section 1 of TIA-968-A.
10
11
12
13
14
Figure 9.2-1. Network Control Signal Power, Two-Wire
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4
5
6
7
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
8
9
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
10
11
(3)
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the figures of Section 1 of TIA-968-A.
12
13
14
15
16
17
Figure 9.2-2. Network Control Signal Power, Four-Wire
18
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9.3
Through-Transmission Equipment – DC Conditions for On-Premises
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
36
9.3.3 Equipment
37
NOTE: Refer to Section 5.3 for equipment details.
38
39
40
9.3.4 Equipment States Subject to Test
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 TIA-968-A, the dc conditions provided to the attached equipment
must fall within the range of conditions it would normally encounter if connected directly
to the PSTN. When checking for compliance, the range of resistances presented by the
attached equipment and the wiring that may be used to connect it must be taken into
account.
The maximum open circuit voltage provided by the loop simulator circuit shown in Figure
1.1 of 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 TIA-968-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 TIA-968-A).
The minimum current test condition is based on the criteria in the network interface
standard T1.401-2000. 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.
DC voltmeter SEL# 22.
DC current meter SEL# 19.
Idle and Active state.
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9.3.5 Procedure
(1)
Configure the EUT for normal operation.
4
5
(2)
Measure and record the open circuit voltage provided for powering the attached
equipment.
6
(3)
Connect the EUT to the test circuit of Figure 9.3-1.
7
8
(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.
9
10
(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.
11
12
13
14
15
9.3.6 Alternative Methods
16
17
18
9.3.7 Suggested Test Data
(1)
The open circuit voltage.
19
(2)
Short circuit current.
20
(3)
Maximum external resistance supported by the EUT if greater than 430 ohms.
21
22
(4)
Current at 430 ohms or at the maximum external resistance supported by the EUT, if
greater than 430 ohms.
None suggested.
23
24
25
26
27
28
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
source of the EUT through-path does not have adequate current limiting.
29
30
83
Tip
EUT
Ring
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2
3
4
5
6
Port for
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Figure 9.3-1. DC Conditions for Through Transmission
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9.4
Through-Transmission Equipment – Data TIA-968-A 4.5.2.3.2
2
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9.5
Voiceband Signal Power - Data TIA-968-A, 4.5.2.4
3
4
5
6
7
8
9
10
9.5.1 Background
11
12
13
14
9.5.2 Purpose
15
16
17
9.5.3 Equipment
18
19
20
9.5.4 Equipment States Subject to Test
21
22
23
9.5.5 Procedure
24
25
(2) Verify that the equipment is not equipped with either the universal or programmed data
jack configuration.
26
27
28
9.5.6 Alternative Methods
29
30
31
32
9.5.7 Suggested Test Data
33
34
35
9.5.8 Comments
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
certified in accordance with TIA-968-A Section 4.5.2.4. The requirement 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 TIA-968-A Section 4.5.2.4.
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.
(1) 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.
None.
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9.5.9
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.
9
10
9.5.10 Purpose
11
To verify that the data signal power level transmitted to the PSTN is properly limited.
12
13
14
9.5.11 Equipment
(1)
Applicable loop simulator SEL# 4.
15
(2)
Bandpass filter SEL# 5.
16
(3)
DC current meter SEL# 19.
17
(4)
True rms ac voltmeter SEL# 40.
18
NOTE: Refer to Section 5.3 for equipment details.
19
20
21
9.5.12 Equipment States Subject To Test
22
23
24
25
9.5.13 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.
26
(2)
Set the voltmeter to measure the signal level in dBm.
27
(3)
Place the EUT in the off-hook state and cause it to transmit a desired data signal.
28
29
(4)
Measure and record the maximum signal power level in dBm at minimum and
maximum loop currents attainable with the loop simulator, if applicable.
30
(5)
Repeat step (3) and step (4) for the other data signals, if applicable.
31
(6)
Repeat step (3) and step (4) for the other operating states, if applicable.
32
(7)
Repeat step (3) and step (4) for other specified jack configurations, if applicable.
Any off-hook state in which data is transmitted to the PSTN.
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2
3
4
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.
5
6
7
8
9.5.14 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).
9
(2)
Set the signal analyzer to measure the following:
10
(g)
Signal level in dBm, 600 ohms.
11
(h)
Averaging over 3 second.
12
(i)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
13
14
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
15
(3)
Place the EUT in the desired off-hook state and transmit a desired data signal.
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) through step (4) for other data signals, if applicable.
19
(6) Repeat step (2) through step (4) for other operating states, if applicable.
20
(7) Repeat step (2) through step (4) for other specified jack configurations, if applicable.
21
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2
3
4
9.5.15 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
9.5.16 Comments
(1)
All references to dBm are with respect to 600 ohms.
13
(2)
The insertion loss of bandpass filter must be taken into account.
14
(3)
For network control signals, see Section 8.2.
15
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2
3
4
5
6
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
7
8
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
9
10
(3)
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the figures of Section 1 of TIA-968-A.
11
12
13
14
(4)
For programmed data equipment, measurements shall 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.
15
16
17
18
Figure 9.5-1. Voiceband Signal Power, Data, TE
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9.6
Through-Transmission – Port to Port Amplification TIA-968-A Par 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
NOTE: Refer to Section 5.3 suggested equipment list (SEL) for equipment details.
24
25
26
9.6.4 Equipment States Subject to Test
27
28
29
30
31
32
33
34
35
36
9.6.5 Procedure
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 TIA 968-A Section 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.
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.
(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
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2
the test circuits of Figure 9.6-2 and Figure 9.6-3. Establish a connection between the
ports under test.
3
4
(2) Set switch S1 to position "A." Adjust the filter to pass the band of frequencies below
3995 Hz.
5
(3) NOTE: If the EUT is band limited, then an appropriate filter adjustment is to be made.
6
7
(4) Establish a through-transmission connection in the direction of the network interface
under test.
8
9
(5) Set the output level of the white noise generator so that the voltmeter indicates -11
dBV. Maintain this level for all tests.
10
11
(6) Set switch S1 to position "B" and measure the signal present at the output side of the
EUT.
12
13
(7) Calculate the gain of the through-transmission path from the input level set in step (4)
and the output level measured in step (5).
14
15
(8) Repeat step (1) through step (6) for the opposite direction of transmission of the EUT, if
applicable.
16
(9) Repeat step (2) through step (7) for each of the following conditions as applicable:
17
(10)
Minimum current through EUT input and maximum current through EUT output;
18
(11)
Maximum current through EUT input and maximum current through EUT output;
19
(12)
Maximum current through EUT input and minimum current through EUT output.
20
21
22
9.6.6 Alternative Methods
23
24
25
9.6.7 Suggested Test Data
26
(2) Signal output levels from the EUT.
27
(3) Calculated net amplification or loss, and associated frequency.
28
29
30
9.6.8 Comments
A discrete or swept frequency method may also be used.
(1) Through-transmission paths.
(1) The net amplification may exceed the limit provided the absolute signal power levels
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2
3
4
specified in TIA 968-A Section 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.
5
6
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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
8
9
10
11
12
13
14
15
16
NOTES:
(1) Select the appropriate loop simulator, holding circuit, or termination for the interface of
the EUT.
(2) Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the TIA-968-A Figures 1.1 to 1.12.
(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 TIA-968-A Figure 1.8.
(4) The resistor R1 of the loop simulator may be replaced with the circuit of Figure 1.8
even though other sections of TIA-968-A specifies 600 Ohms (e.g. Table 4.6, Note 1).
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
5
6
7
NOTES
(1) Select the appropriate loop simulator, holding circuit, or termination for the interface of
the EUT.
(2) Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the TIA-968-A Figures 1.1 to 1.12.
8
9
10
(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 TIA-968-A Figure 1.8.
11
12
(4) The resistor R1 of the loop simulator may be replaced with the circuit of Figure 1.8
even though other sections of TIA-968-A specifies 600 Ohms (e.g. Table 4.6, Note 1).
13
14
15
16
Figure 9.6-2. Through Transmission, Digital
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2
3
4
5
6
7
8
9
10
11
12
13
14
Figure 9.6-3. Digital EUT Arrangement for Figure 9.6-2
9.6.9
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9.7
Through-Transmission - SF Cutoff TIA-968-A Par 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 section 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
NOTE: Refer to Section 5.3 for equipment details.
26
27
28
9.7.4 Equipment States Subject to Test
29
30
31
32
9.7.5 Procedure
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-to2450-Hz band within 20 ms of application of signal.
(1) Applicable loop simulator SEL# 4.
Off-hook states with connection for through transmission.
(1) Connect the EUT to the test circuit of Figure 9.7-1. Establish a connection between the
ports under test.
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(2) Set switch S1 to position "A" and switch S2 to position "B."
2
(3) Adjust the output level of the white noise generator to read -15 dBV on the voltmeter.
3
(4) Set switch S1 to position "B" and switch S2 to position "A."
4
(5) Adjust the output of the frequency generator to read -14 dBV on the voltmeter.
5
6
(6) Set switch S1 to position "A," and measure on the oscilloscope time between the
switch closure and the moment of signal cutoff.
7
8
9
9.7.6 Alternative Methods
10
11
12
9.7.7 Suggested Test Data
13
(2) Length of time interval when the EUT stops through transmission.
14
15
16
17
9.7.8 Comments
None suggested.
(1) Through-transmission paths.
None.
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2
3
4
5
6
7
8
NOTES:
(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.
9
10
(2) Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the TIA-968-A Figures 1.1 to 1.12.
11
12
(3) The resistor R1 of the loop simulator may be replaced with the circuit of TIA-968-A
Figures 1.8.
13
14
15
Figure 9.7-1. Single Frequency Cut-off
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2
9.8
Through-Transmission - SF/Guard Bands TIA-968-A Par 4.5.2.5.2
3
4
5
6
7
8
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 section is to ensure that a
signal passing through the EUT will not be incorrectly interpreted as the SF signal.
9
10
11
12
13
9.8.2 Purpose
14
15
16
9.8.3 Equipment
17
(2) Frequency generator SEL# 27.
18
(3) Multiplexer/demultiplexer SEL# 32 (if required).
19
(4) True rms voltmeter SEL# 40.
20
21
22
NOTE: Refer to Section 5.3 for equipment details.
To compare the insertion loss for analog and digital equipment in the 800-Hz-to-2450Hz band to the insertion loss in the 2450-Hz-to-2750-Hz band.
(1) Applicable loop simulator SEL# 4.
23
24
25
26
27
9.8.4 Equipment States Subject to Test
28
29
30
31
32
33
34
9.8.5 Procedure
35
(2) Set switch S1 to position "B."
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
Mb/s systems, to the test circuits of Figure 9.8-2 and Figure 9.8-3 and establish
connection between ports under test.
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2
(3)
Set the generator to 800 Hz and adjust the output level to -11 dBV as measured by
the voltmeter (see comment (4)).
3
(4) Set switch S1 to position "A" and measure and record the input level of the EUT.
4
5
(5)
6
(6) Repeat step (2) through step (5) for frequencies of 1000, 2000, 2300, and 2600 Hz.
7
(7) Repeat step (2) through step (6) for each of the following conditions as applicable:
8
(8) Minimum current through EUT input and maximum current through EUT output
9
(9) Maximum current through EUT input and maximum current through EUT output
Calculate the gain at 800 Hz as the difference between the level set in step (3) and
the level measured in step (4).
10
(10)
Maximum current through EUT input and minimum current through EUT output
11
12
13
14
15
16
17
(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.
18
(12)
19
20
21
22
9.8.6 Alternative Methods
23
24
25
9.8.7 Suggested Test Data
26
(2) Frequency or frequency band.
27
(3) Output level.
28
(4) Through transmission paths.
29
(5) Comparison data.
30
(6) Loop simulator currents.
Repeat step (2) through step (8) for the opposite direction, if applicable.
A method employing a white noise source and two bandpass filters may be used.
(1) Input level.
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2
3
4
9.8.8 Comments
5
6
(2) Where a device has several identical ports, only one representative sample of each
through-transmission combination needs to be measured.
7
8
(3) A loop simulator circuit may be used when needed on the input and output ports in
place of the 600 ohm termination.
9
10
11
(1) Measure each combination of port types. Check all other operating modes, such as
conferencing, which might cause variations.
(4) The EUT input test level that should be used in testing protective circuits for
compliance is found in step (5) of Section 9.1 for voice EUT, and in step (5) of Section
9.5 for data EUT.
12
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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
18
Loop Simulator
EUT
(Notes 1 & 2 & 4)
Frequency
Generator
(Note 3)
NOTES:
(1) Select the appropriate loop simulator, holding circuit, or termination for the interface of
the EUT.
19
20
(2) Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the TIA-968-A Figures 1.1 to 1.12.
21
22
23
(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 TIA-968-A Figures 1.8
24
25
(4) The resistor R1 of the loop simulator may be replaced with the circuit of TIA-968-A
Figures 1.8.
26
27
28
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
22
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)
NOTES:
(1) Select the appropriate loop simulator, holding circuit, or termination for the interface of
the EUT.
23
24
(2) Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the TIA-968-A Figures 1.1 to 1.12.
25
26
27
(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 TIA-968-A Figures 1.8
28
29
(4) The resistor R1 of the loop simulator may be replaced with the circuit of TIA-968-A
Figures 1.8.
30
31
32
33
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 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.
20
21
NOTE: Refer to Section 5.3 for equipment details.
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 µF.
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
34
(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").
35
36
(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
Idle state.
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return loss will be a positive value.
2
3
4
9.9.6 Alternative Methods
5
6
7
9.9.7 Suggested Test Data
(1)
Return loss of the EUT at 200, 500, 1000, 2000, and 3200 Hz.
8
(2)
Minimum return loss measured in the 200 Hz to 3200 Hz band.
9
10
11
12
13
A commercial return loss bridge may be used instead of the bridge of Figure 9.9-1.
9.9.8 Comments
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
8
9
10
11
Figure 9.9-1. Return Loss, Two-Wire
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9.10
Return Loss, Tie Trunk - Four Wire 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. Section 9.10 deals with
four-wire return loss and Section 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
17
18
NOTE: Refer to Section 5.3 for equipment details.
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.
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
33
34
(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.
Idle state.
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(5)
Connect the EUT to the test circuit as shown in Figure 9.10-2.
2
(6)
Repeat step (2) through step (4).
3
4
5
9.10.6 Alternative Methods
6
7
8
9
9.10.7 Suggested Test Data
A commercial return loss bridge may be used instead of the bridge of Figure 9.10-1.
(1)
Return loss of the tip and ring leads of the EUT at 200, 500, 1000, 2000, and 3200
Hz.
10
11
(2)
Minimum return loss of the tip and ring leads of the EUT measured in the 200-Hz-to3200-Hz band.
12
13
(3)
Return loss of the tip 1 and ring 1 leads of the EUT at 200, 500, 1000, 2000, and
3200 Hz.
14
15
(4)
Minimum return loss of the tip 1 and ring 1 leads of the EUT measured in the 200-Hzto-3200-Hz band.
16
17
18
19
20
21
9.10.8 Comments
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
7
8
9
10
Figure 9.10-1. Return Loss, Four-Wire, T&R
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4
5
6
7
8
9
10
11
Figure 9.10-2. Return Loss, Four-Wire, T1&R1
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9.11
Transducer Loss, Tie Trunk - Four Wire TIA-468-A, 4.5.2.6.3
2
3
4
9.11.1 Background
5
6
7
8
9
9.11.2 Purpose
Refer to Section 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
NOTE: Refer to Section 5.3 for equipment details.
16
17
18
19
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
7
8
9
10
NOTE:
The source impedance of the tracking generator is 600 Ohms.
Figure 9.11-1. Transducer Loss, Forward
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5
6
7
8
9
10
11
12
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 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 Section
8.3).
8
9
10
11
12
9.12.2 Purpose
13
14
15
9.12.3 Equipment
(2)
Applicable loop simulator SEL# 4
16
(3)
DC current meter SEL# 19.
17
(4)
DC voltmeter SEL# 22.
18
19
NOTE: Refer to Section 5.3 for equipment details.
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.
20
21
22
9.12.4 Equipment States Subject To Test
23
24
25
26
27
28
9.12.5 Procedure
(1)
Connect the EUT to test circuit of Figure 9.12-1.
29
(2)
Place the EUT into the talking state.
30
31
(3)
For Class B and Class C OPS interfaces, close switch S1, and measure the short circuit current
between T(OPS) and R(OPS).
32
(4)
Open switch S1.
33
(5)
Place the OPS simulator into condition "1."
34
(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
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/TIA-968-A, 4.4.1.4.1 and the test procedures are covered in Section 8.3
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interfaces.
2
(7)
Record the current flowing in the circuit.
3
(8)
Place the simulator circuit into condition "2" and repeat step (5) through step (7).
4
5
6
9.12.6 Alternative Methods
7
8
9
9.12.7 Suggested Test Data
None suggested.
(1)
Short circuit current (mA) for Class B and C OPS interfaces.
10
(2)
Minimum current under conditions "1" and "2" for Class B and C OPS interfaces.
11
12
13
14
9.12.8 Comments
(1)
The minimum and maximum current requirements do not apply to Class A OPS interfaces. See
Section 8.3 for Class A OPS limitations.
15
16
(2)
The dc current into the OPS loop simulator circuit must 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.
17
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2
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4
5
6
7
8
9
10
11
12
NOTE: Loop current is measured with a current meter in series with the OPS loop
simulator. Refer to the 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 TIA-968-A, 4.5.3.1
2
3
4
5
6
7
8
9
10
11
12
9.13.1 Background
13
14
15
16
17
9.13.2 Purpose
18
19
20
9.13.3 Equipment
(1)
Applicable loop simulator SEL# 4.
21
(2)
Bandpass filter SEL# 8
22
(3)
True rms ac voltmeter SEL# 40.
23
24
25
NOTE: Refer to Section 5.3 for equipment details.
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 must 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.
26
27
28
9.13.4 Equipment States Subject To Test
(1)
Off-hook, idle state.
29
30
(2)
Any off-hook state which transmits signals to the PSTN which are not intended for
network control.
31
32
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4
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
21
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
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
9.13.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
10
11
12
13
(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.
14
15
(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.
16
17
18
(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.
19
20
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3
4
5
6
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
7
8
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
9
10
(3)
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the figures of Section 1 of TIA-968-A.
11
12
13
14
15
Figure 9.13-1. Signal Power, 3995-4005 Hz, Internal Sources
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2
9.14 Through Transmission – 3995-4005 Hz vs 600-4000 Hz TIA-968-A, 4.5.3.2
3
4
5
6
7
9.14.1 Background
The basis for this requirement is identical to that described in Section 9.13
8
9
10
11
12
9.14.2 Purpose
13
14
15
9.14.3 Equipment
(1)
Applicable loop simulator SEL# 4.
16
(2)
Bandpass filter SEL# 8
17
(3)
Bandpass filter SEL# 14.
18
(4)
Frequency generator SEL# 27
19
(5)
True rms ac voltmeter SEL# 40.
20
(6)
White noise generator SEL# 45.
21
22
23
NOTE: Refer to Section 5.3 for equipment details.
24
25
26
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.
9.14.4 Equipment States Subject To Test
(1)
All equipment with through-transmission paths to the PSTN are subject to test.
27
28
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4
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
10
(4)
Adjust the level of the white noise generator so that the voltmeter indicates -11
dBV.
11
12
(5)
Set switch S1 to position "B" and measure the signal present at the output side of
the EUT.
13
14
(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).
15
(7)
Set switch S1 to position "A" and switch S2 to position "B."
16
17
(8)
Set the frequency generator to 4000 Hz and adjust the level to match the level in
step (4).
18
(9)
Set switch S1 to position "B" and measure the signal level.
19
(10)
Calculate the gain at 4000 Hz from the level obtained in step (8) and (9).
20
(11)
Repeat step (2) through step (10) for each of the following conditions as applicable:
21
(12)
Minimum current through EUT input and maximum current through EUT output.
22
(13)
Maximum current through EUT input and maximum current through EUT output.
23
(14)
Maximum current through EUT input and minimum current through EUT output.
24
25
26
27
28
29
9.14.6 Alternative Methods
A discrete or swept frequency method may also be used.
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2
3
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
NOTES:
(1)
(2)
(3)
(4)
Select the appropriate loop simulator, holding circuit, or termination for the interface
of the EUT.
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
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 TIA-968-A.
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the figures of Section 1 of TIA-968-A.
Figure 9.14-1 Signal Power, 3995-4005 Hz vs 600-4000 Hz, Through Transmissio
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3
9.15 Non-LADC Longitudinal Voltage – 0.1 - 4 kHz TIA-968 Par 4.5.4
4
5
9.15.1 Background
6
7
8
9
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
9.15.2 Purpose
12
13
14
To verify that the EUT does not apply excessive longitudinal power to the PSTN in the
voiceband.
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
22
23
NOTE: Refer to Section 4.3 for equipment details.
24
25
9.15.4 Equipment States Subject to Test
26
(1)
On-hook.
27
(2)
All active operating states.
28
29
30
31
32
33
34
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 shall 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 shall be connected to the test
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2
3
4
5
ground plane. Equipment which does not contain any of these potential connections to
ground shall 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
9.15.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.15-1.
9
(2)
Place the EUT in the on-hook state.
10
11
12
(3)
Set the bandpass filter to measure in the 100 Hz to 4000 Hz band and record the
voltmeter reading. The weighting network shall have a transfer function of F/4000,
where F is the frequency in Hz.
13
14
15
16
17
18
NOTE: The measured result must be corrected for the voltage divider relationship of the
termination. Adjustment is +3.1 dB.
(4)
Place the EUT in one of the off-hook states. These tests must be conducted in
accordance with the conditions of TIA-968-A Section 4.5.7.1 to 4.5.7.3, as
appropriate (see comment 3 and 4).
19
(5)
Repeat step (3) for all possible off-hook states.
20
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
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.
27
(2)
Place the EUT in the on-hook state.
28
29
(3)
Set the spectrum analyzer to measure in the 100 Hz to 4000 Hz band and record the
result. See comment (2).
30
31
32
33
34
35
NOTE: The measured result must be corrected for the voltage divider relationship of the
termination. Adjustment is +3.1 dB.
(4)
Place the EUT in one of the off-hook states. These tests must be conducted in
accordance with the conditions of TIA-968-A Section 4.5.7.1 to 4.5.7.3, as
appropriate (see comment 3 and 4).
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(5)
Repeat step (3) for all possible off-hook states.
2
3
4
5
6
7
8
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.
9
10
11
9.15.7 Suggested Test Data
(1)
Band measured.
12
(2)
Voltage level in dBV.
13
(3)
Equipment states.
14
15
16
17
18
19
20
21
22
9.15.8 Comments
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
(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.
(2)
When using a spectrum analyzer the total rms voltage over the 100 Hz to 4 kHz band
can be calculated using the expression:
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.
(a)
(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 Hz signal that is 10 dB higher then the overload level point.
(5)
See TIA-968-A Section 4.5.7.1 through 4.5.7.3 for the conditions that apply for
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2
3
different equipment types.
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2
3
4
5
6
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
7
8
(2)
Connect the resistive network in place of R1 of the loop simulator. Refer to the figure
4.5 of TIA-968-A. The 300 Ohms resistors shall be adequately matched.
9
10
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968-A.
11
12
13
14
15
16
Figure 9.15-1. Voiceband Longitudinal Voltage
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2
9.16 Non-LADC Metallic Voltage - 4 kHz to 30 MHz TIA-968 Par 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
9.16.1 Background
31
32
33
34
9.16.2 Purpose
35
36
37
9.16.3 Equipment
(1)
Applicable loop simulator SEL# 4.
38
(2)
Bandpass filter SEL# 9
39
(3)
Digital sampling storage oscilloscope SEL# 24.
40
(4)
Spectrum analyzer SEL# 34
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 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.
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(5)
Frequency Generator SEL# 27
2
3
NOTE: Refer to Section 4.3 for equipment details.
4
5
6
9.16.4 Equipment States Subject to Test
(1)
On-hook.
7
(2)
All active operating states.
8
9
10
11
12
9.16.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.16-1.
13
(2)
Place the EUT in the on-hook state.
14
(3)
Select R1 to be 300 ohms.
15
16
(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.
17
(5)
Select R1 to be 135 ohms.
18
19
(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.
20
21
(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.
22
23
24
(8)
Place the EUT in each of its off-hook states as specified in TIA-968-A Section
4.5.7.2, and condition the EUT as specified in TIA-968-A Section 4.5.7.3 or 4.5.7.4,
as appropriate (see comment 7 and 8).
25
26
(9)
Repeat step (3) through 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 9.16-2, 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).
30
(11) Condition the EUT to the on-hook state.
31
(12) Set the digital oscilloscope to provide:
NOTE: See comments (1), (2), (3) and (6) before performing tests.
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(a)
2 µs per sample;
2
(b)
Trigger at -25 dBV;
3
(c)
Accumulate mode;
4
(d)
Vertical scale 0 mV to 250 mV full height.
5
6
7
8
NOTE: If the baseline contains 1000 points then a single trace will take 2 ms.
(13) Program the oscilloscope to accumulate 10 traces.
9
10
(14) Record the value of the largest peak measured and convert to V rms by multiplying
by 0.707.
11
12
13
(15) With the EUT in each of its active operating states as specified in TIA-968-A Section
4.5.7.2, condition the EUT as specified in TIA-968-A Section 4.5.7.3 or 4.5.7.4, as
appropriate (see comment 7 and 8).
14
15
(16) Repeat step (13) and step (14) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
16
17
18
19
20
9.16.6 Alternative Method - Broadband Procedure
(1)
Connect the EUT to the test circuit of Figure 9.16-1.
21
(2)
Place the EUT in the on-hook state.
22
(3)
Select R1 to be 300 ohms.
23
24
(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.
25
(5)
Select R1 to be 135 ohms.
26
27
(6)
Set the spectrum analyzer to measure broadband energy in the frequency range 8
kHz to 94 kHz, and record the result.
28
29
(7)
Set the spectrum analyzer to measure broadband energy in the frequency range 86
kHz to 270 kHz, and record the worst case result.
30
31
(8)
Set the spectrum analyzer to measure broadband energy in the frequency range 270
kHz to 6 MHz, and record the worst case result.
NOTE: See comments (2), (3), and (5).
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2
(9)
3
4
5
(10) Place the EUT in each of its off-hook states as specified in TIA-968-A Section
4.5.7.2, and condition the EUT as specified in TIA-968 Section 4.5.7.3 or 4.5.7.4, as
appropriate (see comment 7 and 8).
6
7
(11) Repeat step (3) through step (9) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
8
9
10
(12) If the test results obtained in step (4) and step (6) through step (9) do not exceed the
maximum limits specified in TIA-968 Section 4.5.5.1, then no further tests are
required (see comment 2).
11
12
13
9.16.7 Suggested Test Data
(1)
Center frequencies.
14
(2)
Start and stop frequencies.
15
(3)
Measured or calculated signal power values.
16
(4)
Equipment state.
17
18
19
20
21
22
23
24
9.16.8 Comments
25
26
27
28
29
30
31
32
33
34
35
36
Set the spectrum analyzer to measure broadband energy in the frequency range 6
MHz to 30 MHz, and record the worst case result.
When using a detector that measures individual frequency components, the following
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.
(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 Section 9.16.5 should be used when the requirements are not met as
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2
the signal levels in each band may still be within specified limits. Refer to TIA-968-A
Section 4.5.5.1.
3
4
5
(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.
6
7
8
(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.
9
(5)
The total rms voltage over an 8 kHz band can be calculated using the expression:
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
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.
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 TIA-968-A Section 4.5.7.2 through 4.5.7.4 for the conditions that apply for
different equipment types.
29
30
31
32
(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.
33
34
(8)
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:
35
36
37
38
39
(a)
For approved data protective circuits, apply a 1000 Hz signal that is 10 dB
higher then the overload point as determined in Section x.x.
(b)
For approved terminal equipment or approved protective circuits with nonapproved signal source input, such as music on hold, apply a swept sinusoidal
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2
signal with a frequency range of 200 Hz to 20 kHz and the level set at the
overload point determined in Section x.x.
3
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2
3
4
5
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
6
7
(2)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968-A.
8
9
10
11
(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.
12
13
(4)
The spectrum analyzer should provide a balanced input, or an isolation transformer
or balun transformer may be used.
14
15
16
Figure 9.16-1. Non-LADC Metallic 4 kHz to 30 MHz
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2
3
4
5
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
6
7
(2)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968-A.
8
9
10
(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.
11
12
(4)
The oscilloscope should provide a balanced input, or an isolation transformer or
balun transformer may be used.
13
14
15
16
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 TIA-968 Par 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 Section 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
19
20
21
NOTE: Refer to Section 4.3 for equipment details.
To verify that the EUT does not apply any excessive out-of-band longitudinal signal
power to the PSTN.
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
33
34
35
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 shall 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 shall be connected to the test
ground plane. Equipment which does not contain any of these potential connections to
ground shall 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
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2
3
4
5
6
9.17.5 Procedure
(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 shall 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: The results measured in step (6) and step (7) must be corrected 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 TIA-968-A Section
4.5.7.2, and condition the EUT as specified in TIA-968-A Section 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).
30
(11) Place the EUT in the on-hook state.
NOTE: See comments (1), (2), (3) and (5).
31
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(12) Set the digital oscilloscope to provide:
2
(a)
2 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
NOTE: If the baseline contains 1000 points then a single trace will take 2 ms.
(13) Program the oscilloscope to accumulate 10 traces.
10
11
(14) Record the value of the largest peak measured and convert to V rms by multiplying
by 0.707.
12
13
Note: The results measured in step (14) must be corrected for the voltage divider
relationship of the termination. Adjustment is +4 dB.
14
15
16
(15) With the EUT in each of its active operating states as specified in TIA-968-A Section
4.5.7.2, condition the EUT as specified in TIA-968-A Section 4.5.7.1, 4.5.7.3 or
4.5.7.4, as appropriate (see comment 9 and 10).
17
18
(16) Repeat step (13) and step (14) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
19
20
21
22
9.17.6 Alternative Methods - Broadband Procedure
(1)
Connect the EUT to the test circuit of Figure 9.17-1.
23
(2)
Place the EUT in the on-hook state.
24
(3)
Select the R1 = R2 = 150 ohms and R3 = 425 ohms.
25
26
(4)
Set the spectrum analyzer to measure broadband energy in the 4 kHz to 16 kHz
band and record the result.
27
28
NOTE: The results in step (4) must be corrected by +1.4 dB to accommodate the
voltage divider.
29
(5)
Select R1 = R2 = 67.5 ohms and R3 = 56.3 ohms.
30
(6)
Set the spectrum analyzer to measure broadband energy in the 12 kHz to 46 kHz
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band and record the result.
2
3
(7)
Set the spectrum analyzer to measure broadband energy in the 42 kHz to 270 kHz
band and record the worst case result.
4
5
(8)
Set the spectrum analyzer to measure broadband energy in the 270 kHz to 6 MHz
band and record the worst case result.
6
7
NOTE: The results in step (6) and step (8) must be corrected by +4 dB to accommodate
the voltage divider.
8
9
10
(9)
11
12
(10) Repeat step (3) through step (8) at minimum and maximum loop currents attainable
with the loop simulator, if applicable.
13
14
15
9.17.7 Suggested Test Data
(1)
Center frequencies.
16
(2)
Start and stop frequencies.
17
(3)
Power levels, measured or calculated.
18
(4)
Equipment state.
19
20
21
22
9.17.8 Comments
(1)
When measuring with a detector that measures individual frequency components, the
following procedure should be used.
23
24
25
26
(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.
27
28
29
30
31
32
Place the EUT in each of its off-hook states as specified in TIA-968-A Section
4.5.7.2, and condition the EUT as specified in TIA-968 Section 4.5.7.1, 4.5.7.3 or
4.5.7.4, as appropriate (see comment 9 and 10).
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.
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2
3
4
5
6
7
(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 Section 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 TIA-968-A Section 4.5.5.2.
8
9
10
(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.
11
12
13
(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.
14
15
(7)
The total rms voltage over an 8 kHz band can be calculated by the following
impression:
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
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 TIA-968-A Section 4.5.7.1 through 4.5.7.4 for conditions that apply for different
equipment types.
32
33
34
35
(9)
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.
36
37
(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:
38
39
(a)
For approved data protective circuits, apply a 1000 Hz signal that is 10 dB
higher then the overload point as determined in Section x.x.
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2
3
4
5
6
7
8
9
10
11
12
(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 Section x.x.
(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.
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
13
14
15
(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.
16
17
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968-A.
18
19
Figure 9.17-1. Non-LADC Longitudinal
4 kHz to 6 MHz
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2
3
4
5
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
6
7
8
(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.
9
10
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968-A.
11
12
13
14
Figure 9.17-2. Non-LADC Longitudinal 270 kHz to 6 MHz
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9.18
2
9.18.1 Background
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Metallic Voltage - 0.01 kHz to 6 MHz, LADC TIA-968-A Par 4.5.6.1, 4.5.6.2
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.
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.
33
34
35
NOTE: Refer to Section 5.3 for equipment details.
To verify that the EUT does not apply excessive metallic power to the network for
LADC equipment.
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2
3
4
9.18.4 Equipment States Subject to Test
5
6
9.18.5 Procedure
7
8
NOTE: Refer to 4.5.7.5 through 4.5.7.8 for applicable test conditions.
Active and transmitting data.
9
10
9.18.6 Frequencies Below 4 kHz TIA-968-A, 4.5.6.1
11
(1) Connect the EUT to the test circuit of Figure 9.18-1.
12
(2) Select the 10-Hz-to-4000-Hz bandpass filter.
13
14
(3) Cause the EUT to transmit an output signal in accordance with TIA-968-A, Section
4.5.7.6 and 4.5.7.7.
15
(4) Record the voltmeter reading.
16
(5) Repeat step (3) and step (4) for all possible states.
17
18
19
20
NOTE: The remaining steps are only applicable to four-wire EUTs.
(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
6
7
8
9
9.18.7
100 Hz Bands in the Frequency Range 0.7 kHz to 4kHz TIA-968-A,
4.5.6.1.2
100 Hz Bands in the Frequency Range 4 kHz to 270 kHz TIA-968-A,
4.5.6.2.1
NOTE: See comments (1) and (2).
(1) Connect the EUT to the test circuit of Figure 9.18-3.
10
11
(2) Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of TIA-968-A.
12
(3) Measure the rms voltage averaged over 100 ms with a bandwidth of 100 Hz.
13
14
15
(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.
16
17
18
(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.
19
20
21
(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.
22
23
24
(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.
25
26
27
(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.
28
(9) Repeat step (2) through step (8) for all operating conditions.
29
30
31
32
33
NOTE: The remaining steps are only applicable to four-wire EUTs.
(10) Connect the EUT to the test circuit of Figure 9.18-4.
(11) Repeat step (2) through step (9).
34
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2
3
4
9.18.8 8kHz bands Over the Frequency Range of 4 kHz to 270 kHz TIA-968-A,
4.5.6.2.2
5
6
(2) Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of 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
16
17
18
NOTE: The remaining steps are only applicable to four-wire EUTs.
(7) Connect the EUT to the test circuit of Figure 9.18-4.
19
(8) Repeat step (2) through step (6).
20
21
22
23
24
9.18.9 RMS Voltages at Frequencies Above 270 kHz TIA-968-A, 4.5.6.2.3
25
(2) Select the 270-kHz-to-30-MHz bandpass filter.
26
(3) Set the digital oscilloscope to provide:
NOTE: See comments (1), (2) and (3).
(1) Connect the EUT to the test circuit of Figure 9.18-5.
27
(a)
2 µs per sample;
28
(b)
Trigger at -25 dBV;
29
(c)
Accumulate mode;
30
(d)
Vertical scale 0 mV to 100 mV full height.
31
32
NOTE: If the baseline contains 1000 points then a single trace will take 2 ms.
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2
(4)
Program the oscilloscope to accumulate 10 traces.
3
4
(5)
Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7.
5
6
(6)
Record the value of the largest peak measured and convert to V rms by multiplying
by 0.707.
7
8
9
NOTE: The remaining steps are only applicable to four-wire EUTs.
(7)
Connect the EUT to the test circuit of Figure 9.18-6.
10
(8)
Repeat step (2) through step (6).
11
12
13
14
15
9.18.10 Peak Voltages at Frequencies Above 4 kHz TIA-968-A, 4.5.6.2.4
16
(2) Select the 4 kHz-to-30-MHz bandpass filter.
17
(3) Set the digital oscilloscope to provide:
NOTE: See comments (1) and (2).
(1) Connect the EUT to the test circuit Figure 9.18-5.
18
(a)
2 µs per sample;
19
(b)
Trigger at 0.4 V peak;
20
(c)
Accumulate mode;
21
(d)
Vertical scale 0 V to 5 V full height.
22
(4) Accumulate peak readings for a 10-second period.
23
24
(5) Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of TIA-968-A.
25
(6) Record the value of the largest peak measured.
26
27
28
29
30
NOTE: The remaining steps are only applicable to four-wire EUTs.
(7) Connect the EUT to the test circuit of Figure 9.18-6.
(8) Repeat step (2) through step (6).
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2
9.18.11 Alternative Methods
3
None suggested.
4
5
9.18.12 Suggested Test Data
6
(1) Center frequencies measured or frequency band measured.
7
(2) Voltage levels, measured or calculated.
8
(3) Equipment state.
9
10
9.18.13 Comments
11
(1) A quasi-random signal source may be used for testing.
12
(2) See TIA-968-A, Sections 4.5.7.5 through 4.5.7.8 further information.
13
14
15
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2
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4
Figure 9.18-1. LADC Metallic 10 Hz to 4 kHz, T&R
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5
6
7
Figure 9.18-2. LADC Metallic 10 Hz to 4 kHz, T1 & R1
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2
3
4
5
6
7
8
9
10
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
8
9
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
5
6
7
8
9
NOTES:
The oscilloscope should provide a balanced input.
Refer to the procedure for selection of the appropriate bandpass filter.
Figure 9.18-5. LADC Metallic 270 kHz to 30 Mhz, T&R
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2
3
4
5
6
NOTES:
7
Refer to the procedure for selection of the appropriate bandpass filter.
8
9
10
The oscilloscope should provide a balanced input.
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 TIA-968-A Par 4.5.6.3
2
3
4
5
6
7
8
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.
9
10
11
9.19.2 Purpose
12
13
14
9.19.3 Equipment
(1)
Applicable loop simulator SEL# 4.
15
(2)
Bandpass filter SEL# 9.
16
(3)
Bandpass filter SEL# 11.
17
(4)
Companion terminal equipment SEL# 15.
18
(5)
Digital sampling storage oscilloscope SEL# 24.
19
(6)
Spectrum Analyzer SEL# 34.
20
21
22
NOTE: Refer to Section 5.3 for equipment details.
23
24
25
26
27
28
29
30
31
32
33
34
35
36
To verify that the EUT does not apply excessive longitudinal power to the network.
9.19.4 Equipment States Subject to Test
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, cold-water-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 which
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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3
4
9.19.5 Procedure
5
6
7
9.19.6 Frequencies Below 4 kHz TIA-968-A, 4.5.6.3.1
8
9
(2) Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of TIA-968-A.
NOTE: Refer to Section 4.5.7.5 to 4.5.7.8 for applicable test conditions.
(1)
Connect the EUT to the test circuit of Figure 9.19-1.
10
(3)
Record the maximum spectrum analyzer reading in the test band.
11
(4)
Repeat step (2) and step (3) for all possible states.
12
13
14
NOTE: The remaining steps are only applicable to four-wire EUTs.
(5)
Connect the EUT to the test circuit of Figure 9.19-2.
15
(6)
Repeat step (2) through step (4).
16
17
18
NOTE: The measured result is to be corrected +3.1 dB for the voltage divider
relationship of the termination.
19
20
21
22
9.19.7 8 kHz Bands over the Frequency Range of 4 kHz to 270 kHz TIA-968-A,
4.5.6.3.2
(1)
Connect the EUT to the test circuit Figure 9.19-3.
23
(2)
Select R1=R2=150 ohms and R3=425 ohms.
24
25
(3) Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of TIA-968-A.
26
27
(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.
28
29
NOTE: The measured result is to be corrected for the voltage divider relationship of the
termination. Adjustment is +1.4 dB.
30
31
32
(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)
Select R1=R2=67.5 ohms and R3=56.3 ohms.
2
3
(7) Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of 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
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
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:
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.
27
(a)
2 µs per sample;
28
(b)
Trigger at -25 dBV;
29
(c)
Accumulate mode;
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2
3
4
5
(d)
Vertical scale 0 mV to 100 mV full height.
NOTE: If the baseline contains 1000 points then a single trace will take 2 ms.
(4)
Program the oscilloscope to accumulate 10 traces.
6
7
(5)
Cause the EUT to transmit an output signal in accordance with Section 4.5.7.6 and
4.5.7.7 of TIA-968-A.
8
9
(6)
Record the value of the largest peak measured and convert to V rms by multiplying
by 0.707.
10
11
12
NOTE: The remaining steps are only applicable to four-wire EUTs.
(7)
Connect the EUT to the test circuit of Figure 9.19-6.
13
(8)
Repeat step (2) through step (6).
14
15
16
17
NOTE: The measured result of step (7) is to be corrected +4 dB for the voltage divider
relationship of the termination.
18
19
20
21
9.19.9 Alternative Methods
22
23
9.19.10 Suggested Test Data
24
(1) Center frequencies measured or frequency band measured.
25
(2) Voltage levels, measured or calculated.
26
(3) Equipment state.
None suggested.
27
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2
3
4
9.19.11 Comments
(1)
Reference TIA-968-A, Sections 4.5.7.5 through 4.5.7.8 for further information.
5
(2)
A pseudorandom signal source may be used for testing.
6
7
8
9
(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.
10
11
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2
3
4
5
6
7
8
9
10
NOTE: Ensure proper operation of the EUT while the pair under test is not connected
to the companion terminal equipment. The 300 Ohm resistors should be adequately
matched.
Figure 9.19-1. LADC Longitudinal 10 Hz - 4 kHz, T&R
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2
3
4
5
6
7
8
9
10
NOTE: Ensure proper operation of the EUT while the pair under test is not connected
to the companion terminal equipment. The 300 Ohm resistors should be adequately
matched.
Figure 9.19-2. LADC Longitudinal 10 Hz to 4 kHz, T1 & R1
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
NOTE: Ensure proper operation of the EUT while the pair under test is not
connected to the companion terminal equipment. The resistors R1
and R2 should be adequately matched.
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
12
NOTE: Ensure proper operation of the EUT while the pair under test is not connected
to the companion terminal equipment. The resistors R1 and R2 should be adequately
matched.
Figure 9.19-4. LADC Longitudinal 4 kHz to 270 kHz, T1 & R1
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2
3
4
5
6
7
8
9
10
11
12
13
NOTE: Ensure proper operation of the EUT while the pair under test is not connected
to the companion terminal equipment. The 67.5 Ohm resistors should be adequately
matched.
Figure 9.19-5. LADC Longitudinal 270 kHz to 6 MHz, T & R
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2
3
4
5
6
7
8
9
10
11
NOTE:
Ensure proper operation of the EUT while the pair under test is not
connected to the companion terminal equipment. The 67.5 Ohm resistors should be
adequately matched.
Figure 9.19-6. LADC Longitudinal 270 kHz to 6 Mhz, T1 & R1
12
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2
9.20 Pulse Repetition Rate, Subrate TIA-968-A Par 4.5.8.1.1
3
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2
9.21 Encoded Analog Content TIA-968-A Pars 4.5.8.1.2, 4.5.8.1.8, 4.5.8.4.4
3
9.21.1 1.544 Mb/s Encoded Analog Content TIA-968-A, 4.5.8.2.5
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
9.21.1.1
29
30
31
32
9.21.1.2
33
34
35
9.21.1.3
(1)
Companion terminal equipment SEL# 15.
36
(2)
Multiplexer/demultiplexer SEL# 32.
37
(3)
True rms ac voltmeter SEL# 40.
38
39
Background
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
certified for compliance with the encoded analog limits or is used under a condition that
requires an affidavit that encoded analog content will not be involved or will be properly
adjusted.
Purpose
To verify the maximum equivalent power of the encoded analog content of the
transmitted digital signal.
Equipment
NOTE: Refer to Section 5.3 for equipment details.
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9.21.1.4
4
5
6
7
9.21.1.5
Equipment States Subject to Test
The EUT is to be active and transmitting encoded analog signals.
(1)
Procedure
Connect the EUT to the test circuit of Figure 9.21.1-1. As shown, two types of signals
may be transmitted:
8
9
(a)
Internally generated signals that are generated directly in digital form but
which are intended for eventual conversion to analog form;
10
11
(b)
Internally generated analog signals that are converted to digital format for
eventual reconversion to analog form.
12
13
(2)
For signals of type (a) or type (b) as described above, cause the equipment to
generate each of the possible signals.
14
15
16
(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.
17
18
19
20
9.21.1.6
(1)
Connect the EUT to the test circuit of Figure 9.21.1-1 and replace the true rms ac
voltmeter with a signal analyzer (SEL# 56).
21
(2)
Set the signal analyzer to measure the following:
Alternative Methods
22
(j)
Signal level in dBm, 600 ohms.
23
(k)
Averaging over 3 second.
24
(l)
Band pass power in the frequency range of 200 Hz to 4 kHz band.
25
26
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
27
28
(3)
For signals of type (a) or type (b) as described in section 14.2.5.5, cause the
equipment to generate each of the possible signals.
29
(4)
Measure and record the maximum signal power level in dBm.
30
(5)
Repeat step (2) and step (3) for other internally generated signals.
31
9.21.1.7
Suggested Test Data
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2
The signal measured and the power reading measured.
3
4
5
9.21.1.8
Comments
(1)
The measurement is to be in dBm with respect to 600 Ohms.
6
7
(2)
Both the network control signals and all internally generated signals is to be
measured.
8
9
10
(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.
11
12
13
14
15
16
17
18
Figure 9.21.1-1. 1.544 Mb/s, Encoded Analog Content
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9.22 Equivanent PSD for Maximum Output, Subrate TIA-968-A Par 4.5.8.1.3
3
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2
3
9.23 Average Power, Subrate, Non-Secondary Channel Rates TIA-968-A Par
4.5.8.1.4
4
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9.24 Average Power, Subrate, Secondary Channel Rates TIA-968-A Par 4.5.8.1.5
3
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9.25 Pulse Template, Subrate and PSDS TIA-968-A Par 4.5.8.1.6
3
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2
9.26 Average Power, Subrate TIA-968-A Par 4.5.8.1.7
3
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9.27 Pulse Repetition Rate, 1.544 Mb/s TIA-968-A Par 4.5.8.2.1
3
4
5
9.27.1 Background
6
7
8
9.27.2 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
9.27.3 Equipment
(1)
Data generator SEL# 18.
12
(2)
Spectrum analyzer SEL# 34.
13
14
15
NOTE: Refer to Section 5.3 for equipment details.
16
17
18
9.27.4 Equipment States Subject to Test
19
20
21
22
9.27.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.27-1. Both the transmit pair and the
receive pair should be terminated in the proper resistive loads.
23
24
(2)
Arrange the equipment in accordance with the instruction manual so that it generates
a free-running signal.
25
(3)
Measure the resultant pulse repetition rate.
The EUT is to be active and transmitting a free running signal.
26
27
28
29
9.27.6 Alternative Methods
30
31
32
9.27.7 Suggested Test Data
None suggested.
(1)
Type of signal.
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(2)
Measured pulse repetition rate.
2
3
4
5
9.27.8 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.
6
7
(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.
8
9
10
11
12
13
14
15
Figure 9.27-1. 1.544 Mb/s, Pulse Repetition Rate
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9.28 Output Pulse Template, 1.544 Mb/s TIA-968-A Paragraphs 4.5.8.2.2 & 4.5.8.2.3
3
4
5
6
7
8
9
10
11
12
13
14
9.28.1 Background
15
16
17
18
19
9.28.2 Purpose
20
21
22
9.28.3 Equipment
(1)
DS1 transmission set (SEL# 25) if required.
23
(2)
Digital sampling storage oscilloscope (SEL# 24).
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.
Paragraph 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 Paragraph 4.5.8.2.2 also satisfies the requirements in
Paragraph 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.
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NOTE: Refer to Section 5.3 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.
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(2)
Verify that the output pulse options are selectable at the time of installation, and
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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select output pulse option "A" (0 dB loss at 772 kHz).
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(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.
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(4)
Record a single positive pulse on the oscilloscope, and compare the pulse shape to
the template criteria.
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(5)
Record a single negative pulse on the oscilloscope, and compare the pulse shape to
the template criteria.
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(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).
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9.28.6 Alternative Methods
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9.28.7 Suggested Test Data
(1)
The pulse option.
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(2)
Plots of the isolated pulses relative to the pulse mask templates.
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9.28.8 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.
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(2)
See Appendix A.2 for more information concerning the 1.544 Mb/s pulse templates.
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(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
EUT’s signal.
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, the receive pair must also be terminated into a 100 ohm resistive load.
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Figure 9.28-1. 1.544 Mb/s, Pulse Template connection diagram
Notes to the editor:
In the above figure, the 100 ohm resistor between the data generator and the EUT
should be eliminated and the description changed from data generator to DS1
TRANSMISSION SET.
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9.29 Output Power, 1.544 Mb/s TIA-968-A Par 4.5.8.2.4
9.29.1 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.
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9.29.2 Purpose
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9.29.3 Equipment
(1)
Data generator SEL# 18.
16
(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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NOTE: Refer to Section 5.3 for equipment details.
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9.29.4 Equipment States Subject to Test
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9.29.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.29-1 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 Section 14.2.4.6.
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9.29.6 Alternative Method
(1)
Connect the EUT to the test circuit of Figure 9.29-1, 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.
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4
10 * log  * v*.707

 30
P772k ( dBm) 
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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 Section
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 9.29-1.
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Table 9.29-1. Correction Factors for 1.544 Mb/s Output Power
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3
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
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9.29.7 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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9.29.8 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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NOTE : The spectrum analyzer should provide a high-impedance, balanced input.
Figure 9.29-1. 1.544 Mb/s, Output Power
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9.30 Unequipped Sub-rate Channels TIA-968-A, 4.5.8.2.6
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9.30.1 Background
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9.30.2 Purpose
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9.30.3 Equipment
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9.30.4 Equipment States Subject to Test
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9.30.5 Procedure
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9.30.6 Alternative Methods
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9.30.7 Suggested Test Data
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9.30.8 Comments
For connections to 1.544 Mbps digital services, the permissible code words for
unequipped µ255 encoded sub-rate channels 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 section 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 section under all operating conditions.
None suggested.
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9.31 Pulse Repetition Rate, PSDS (Types II and III) TIA-968-A Par 4.5.8.3.1
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9.33 Conditioning ADSL EUT to Transmit Continuously TIA-968-A Par 4.5.8.3.2
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9.34 Aggregate Signal Power, ADSL Terminal Equipment TIA-968-A Par 4.5.9.1
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9.34.1 Background
The aggregate signal power, or total power, of the ADSL modem must be 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.
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9.34.2 Purpose
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9.34.3 Equipment
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9.34.4 Equipment States Subject to Test
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9.34.5 Procedure
To verify that the signal power level transmitted to the network is properly limited.
True rms ac voltmeter SEL#41.
100 , 1 %, non-inductive resistor.
NOTE: Refer to Section 5.3 for equipment details.
Transmitting continuously at its highest signal power and upstream line data rate.
Condition the EUT to transmit at it highest upstream signal power level and line rate as
described in 8.22.2.
Connect the EUT to the test circuit of Figure 9.34.5-1.
Measure and record the signal power level in dBm.
If the ac voltmeter has its dBm scale referenced to 600 , then a correction factor of
+7.8 dB must be added to the displayed reading to account for the measurement
impedance of 100 .
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FIGURE 9.34.5-1. AVERAGE SIGNAL POWER
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9.34.6 Alternative Methods
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9.34.7 Suggested Test Data
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9.34.8 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 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 8.22.4.
Signal Power Level.
Line Data Rate and Baud Rate if applicable.
It is recommended that the voltmeter provide a high-impedance balanced input
particularly if the EUT has intentional paths to ground. The resistor value in the above
figure is in ohms.
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9.35 Power Spectral Density, ADSL Terminal Equipment TIA-968-A Par 4.5.9.2
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9.35.1 Background
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9.35.2 Purpose
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9.35.3 Equipment
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9.35.4 Equipment States Subject to Test
As is the case for the ADSL modem’s total power, its PSD must be 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.
To verify that the PSD is below the mask.
Spectrum analyzer SEL#57.
100 , 1 % non-inductive resistor.
Differential amplifier with 10X passive probe set and built in LPF SEL#58.
100:50  balun transformer SEL#59.
10 dB, 50  pad SEL#60
500 kHz High Pass Filter SEL#61
Transmitting continuously at its highest signal power and upstream line data rate.
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9.35.5 Procedure
The test procedure is broken down into four sections associated with making the PSD
measurements in a given frequency range segment.
9.35.5.1
Procedure for Segment 1
Condition the EUT to transmit at its highest upstream signal power level and line rate as
described in 8.22.2.
Connect the EUT to the test circuit of Figure 9.35.5.1-1.
Set the differential amplifier for unity gain and a low pass cut-off frequency of 10 kHz.
Set the spectrum analyzer as follows:
Resolution bandwidth: 100 Hz
Video bandwidth: 3 Hz
Attenuation or range: Set for minimum without overload
Reference level: -40 dBm
dB/div: 10 dB
Start frequency: 200 Hz
Stop frequency: 4000 Hz
Marker Function: Noise dBm/Hz
Limit test: On with limit line programmed with the mask’s peak limit
Measure and record the PSD over the first segment of the mask, which covers the voice
frequency band.
NOTES: The PSD readings must be adjusted 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 9.35.5.1-1 is in ohms.
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FIGURE 9.35.5.1-1. PSD CONNECTION DIAGRAM FOR SEGMENTS 1 & 2
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6
FIGURE 9.35.5.1-2. SAMPLE PSD PLOT FOR SEGMENT 1
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9.35.5.2
Procedure for Segment 2
Condition the EUT to transmit at it highest upstream signal power level and line rate as
described in 8.22.2.
Connect the EUT to the test circuit of Figure 9.35.5.1-1.
Set the differential amplifier for unity gain with no filtering
Set the spectrum analyzer as follows:
Resolution bandwidth: 1 kHz
Video bandwidth: 30 Hz
Attenuation or range: Set for minimum without overload
Reference level: -20 dBm
dB/div: 10 dB
Start frequency: 4 kHz
Stop frequency: 26 kHz
Marker Function: Noise dBm/Hz
Limit test: On with limit line programmed with the mask’s peak limit
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.
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FIGURE 9.35.5.2-1. SAMPLE PSD PLOT FOR SEGMENT 2
9.35.5.3
Procedure for Segment 3
Condition the EUT to transmit at it highest upstream signal power level and line rate as
described in 8.22.2.
Connect the EUT to the test circuit of Figure 9.35.5.3-1.
Set the spectrum analyzer as follows:
Resolution bandwidth: 10 kHz
Video bandwidth: 300 Hz
Attenuation or range: Set for minimum without overload
Reference level: -20 dBm
dB/div: 10 dB
Start frequency: 25 kHz
Stop frequency: 525 kHz
Marker Function: Noise dBm/Hz
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8
Limit test: On with limit line programmed with the mask’s peak limit
Measure and record the PSD over the third segment of the mask, which covers the
ADSL operating band on up to 525 kHz.
FIGURE 9.35.5.3-1. PSD CONNECTION DIAGRAM FOR SEGMENT 3
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FIGURE 9.35.4.5.3-2. SAMPLE PSD PLOT FOR SEGMENT 3
9.35.5.4
Procedure for Segment 4
Condition the EUT to transmit at it highest upstream signal power level and line rate as
described in 8.22.2.
Connect the EUT to the test circuit of Figure 9.35.5.4-1.
Set the spectrum analyzer as follows:
Resolution bandwidth: 10 kHz
Video bandwidth: 300 Hz
Attenuation or range: Set for minimum without overload
Reference level: -70 dBm
dB/div: 10 dB
Start frequency: 525 kHz
Stop frequency: 30 MHz
Marker Function: Noise dBm/Hz
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Limit test: On with limit line programmed with the mask’s peak limit and above 1221 kHz
the dashed line mask limit from ANSI T1.413 which will ensure compliance with the –50
dBm total power in a 1 MHz sliding window.
Measure and record the PSD over the fourth segment of the mask, which covers the
high frequencies above the ADSL operating band.
NOTE: The 10 dB pad may be omitted if the high pass filter can withstand high input
levels without introducing distortion products. The PSD readings must be adjusted to
take into account losses introduced by the balun, pad and filter.
FIGURE 9.35.5.4-1. PSD CONNECTION DIAGRAM FOR SEGMENT 4
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FIGURE 9.35.5.4-2. SAMPLE PSD PLOT FOR SEGMENT 4
9.35.6 Alternative Methods
A balun transformer may be used instead of the differential amplifier in section 9.35.5.1
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.
If the PSD exceeds the dashed limit in the mask at any point above 1221 kHz,
measurements must be made to calculate the total power in a 1 MHz sliding window.
This concept was discussed in 8.22.3.6. The peak limit of –90 dBm/Hz, above 1221
kHz, must never be exceeded by any individual spectral component. However, noise
may exceed the dashed line limit provided that the power integrated over a 1 MHz
bandwidth is less than –50 dBm. As the procedure given in 8.22.4.5.4 suggest, the
sliding window calculation is not necessary if the PSD never exceeds the dashed line.
As an example, the dashed line in ANSI T1.413-1998 Figure 32 reaches a noise floor of
–110 dBm/Hz, which over a 1 MHz band is equivalent to –50 dBm.
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9.35.7 Suggested Test Data
Plots of the PSD for each segment with the limit line shown on each graph
Line Data Rate and Baud Rate if applicable.
9.35.8 Comments
Care must be taken to ensure that measurement errors are kept to a minimum.
Sources of error may include the following:
Impedance deviations from the ideal 100  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
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
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9.36
Longitudinal Output Voltage, ADSL Terminal Equipment TIA-968-A Par
4.5.9.3
3
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9.36.1 Background
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9.36.2 Purpose
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29
9.36.3 Equipment
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33
9.36.4 Equipment States Subject to Test
34
35
36
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40
9.36.5 Procedure
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 must also meet certain LOV limits for voiceband terminal equipment.
These measurements should be made using the procedure set out in Sections 8.15 and
8.17.
To verify that the longitudinal output voltage is below the limit.
Spectrum analyzer SEL#57.
LOV Test fixture shown in Figure 8.22.5.5-1
Transmitting continuously at its highest signal power and upstream line data rate.
Condition the EUT to transmit at it highest upstream signal power level and line rate as
described in 8.22.2.
Connect the EUT to the test circuit of Figure 9.36.5-1.
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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: 844 Hz
Marker Function: Voltage dBV
Limit test: On with limit line programmed with the LOV limit
Measure and record the LOV averaging the readings over several sweeps.
NOTES: The resistor values in Figure 9.36.5-1 are in ohms. A resolution bandwidth
(RBW) of 3 kHz is typically used as most spectrum analyzers support this RBW.
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FIGURE 9.36.5-1. LOV TEST FIXTURE & CONNECTION DIAGRAM
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FIGURE 9.36.5-2. SAMPLE LOV PLOT
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9.36.6 Alternative Methods
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9.36.7 Suggested Test Data
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9.36.8 Comments
None
Plot of the LOV with the limit line shown
Line Data Rate and Baud Rate if applicable.
Care must be taken in the construction of the LOV test fixture. Resistor values must be
matched as previously mentioned. 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
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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 Section 9.1.8.
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9.37 Voiceband Signal Power - Non-approved external signal sources TIA-968-A3, Para 4.5.2.2
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7
8
9
10
11
12
9.37.1 Background
13
14
15
16
17
9.37.2 Purpose
18
19
20
9.37.3 Equipment
(1)
Applicable loop simulator SEL# 4
21
(2)
Frequency generator SEL# 27.
22
(3)
True rms ac voltmeter SEL# 40 (qty 2).
23
24
NOTE: Refer to Section 5.3 for equipment details.
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, they
must connect through equipment that ensures appropriate limiting of the signals.
Rationale for the specific limitations is discussed in Section 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.
25
26
27
28
29
9.37.4 Equipment States Subject to Test
30
31
32
9.37.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 9.37-1.
33
34
(2)
Place the EUT in the off-hook state with a mid-range loop current (any current in
the range between 40 mA and 70 mA is acceptable).
35
(3)
Set the frequency generator to a frequency of 1000 Hz and an input level of -50
Test any off-hook state that transmits signals from non-approved equipment to the
PSTN.
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1
dBV. Measure the output level of the EUT.
2
3
(4)
Increase the level of the frequency generator in 1 dB steps and observe the signal
level. (See comment (2)).
4
5
(5)
Determine the category of signal power limiting of the EUT and its input overload
level value (see comment (3)).
6
7
(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).
8
9
(7)
Monitor the signal power at the network interface on the voltmeter while varying the
loop current.
10
11
(8)
Measure and record the maximum signal power level and the corresponding
current.
12
13
(9)
Increase the level of the test signal source to 10 dB above the level in step (6) (see
comment (4)).
14
15
(10)
Record the maximum voltage level at the network interface and verify that limiting
of the signal power level occurs (see comment (5)).
16
17
(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.
18
19
20
9.37.6 Alternative Methods
21
22
23
9.37.7 Suggested Test Data
(1)
Input and output signal power levels.
24
(2)
Test frequencies.
25
(3)
Loop conditions of maximum signal power.
26
27
28
9.37.8 Comments
(1)
All references to dBm are with respect to 600 ohms.
29
30
31
32
(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
loop
None suggested.
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2
the voltmeter.
(3)
There are essentially two categories of signal power limiting circuits:
3
4
5
6
7
8
(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.
9
10
11
12
13
(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.
14
15
(4)
It is not necessary to test the EUT for compliance with input levels greater than
+37 dBV.
16
17
18
19
20
21
22
(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 TIA-968-A Section 4.5.2.1,
is quite restrictive.
23
24
25
26
27
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
have a maximum output level limited to a value 13 dB greater than that specified in TIA968-A Section 4.5.2.1. A protection circuit which is categorized as an AGC device must
limit its output level to the level specified in TIA-968-A Section 4.5.2.1.
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2
3
4
5
6
7
(1)
Select the appropriate loop simulator for the interface of the EUT.
8
9
(2)
Connect the voltmeter (VM2) across R1 of the loop simulator. Refer to TIA-968-A
figures 1.1 to 1.12.
10
11
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to TIA-968-A figures 1.1 to 1.12.
12
13
14
15
16
17
18
19
20
21
Figure 9.37-1. Voiceband Signal Power - Non-approved external signal sources
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2
9.38 Voiceband Signal Power - Non-approved external signal sources TIA-968-A3, 4.5.2.2
3
4
5
6
7
8
9
10
11
12
9.38.1 Background
13
14
15
16
17
9.38.2 Purpose
18
19
20
9.38.3 Equipment
(4)
Applicable loop simulator SEL# 4
21
(5)
Frequency generator SEL# 27.
22
(6)
True rms ac voltmeter SEL# 40 (qty 2).
23
24
NOTE: Refer to Section 5.3 for equipment details.
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, they
must connect through equipment that ensures appropriate limiting of the signals.
Rationale for the specific limitations is discussed in Section 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.
25
26
27
28
29
9.38.4 Equipment States Subject to Test
30
31
32
9.38.5 Procedure
(12)
Connect the EUT to the test circuit of Figure 9.38-1.
33
34
(13)
Place the EUT in the off-hook state with a mid-range loop current (any current in
the range between 40 mA and 70 mA is acceptable).
35
(14)
Set the frequency generator to a frequency of 1000 Hz and an input level of -50
Test any off-hook state that transmits signals from non-approved equipment to the
PSTN.
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1
dBV. Measure the output level of the EUT.
2
3
(15)
Increase the level of the frequency generator in 1 dB steps and observe the signal
level. (See comment (2)).
4
5
(16)
Determine the category of signal power limiting of the EUT and its input overload
level value (see comment (3)).
6
7
(17)
Measure the output signal power level of the EUT when the level applied to the
EUT is the overload value determined in step (5).
8
9
(18)
Monitor the signal power at the network interface on the voltmeter while varying the
loop current.
10
11
(19)
Measure and record the maximum signal power level and the corresponding
current.
12
13
(20)
Increase the level of the test signal source to 10 dB above the level in step (6) (see
comment (4)).
14
15
(21)
Record the maximum voltage level at the network interface and verify that limiting
of the signal power level occurs (see comment (5)).
16
17
(22)
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.
18
19
20
9.38.6 Alternative Methods
21
22
23
9.38.7 Suggested Test Data
(4)
Input and output signal power levels.
24
(5)
Test frequencies.
25
(6)
Loop conditions of maximum signal power.
26
27
28
9.38.8 Comments
(4)
All references to dBm are with respect to 600 ohms.
29
30
31
32
(5)
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
loop
None suggested.
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2
the voltmeter.
(6)
There are essentially two categories of signal power limiting circuits:
3
4
5
6
7
8
(c)
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.
9
10
11
12
13
(d)
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.
14
15
(6)
It is not necessary to test the EUT for compliance with input levels greater than
+37 dBV.
16
17
18
19
20
21
22
(7)
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 TIA-968-A Section 4.5.2.1,
is quite restrictive.
23
24
25
26
27
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
have a maximum output level limited to a value 13 dB greater than that specified in TIA968-A Section 4.5.2.1. A protection circuit which is categorized as an AGC device must
limit its output level to the level specified in TIA-968-A Section 4.5.2.1.
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2
3
4
(4)
Select the appropriate loop simulator for the interface of the EUT.
5
6
(5)
Connect the voltmeter (VM2) across R1 of the loop simulator. Refer to TIA-968-A
figures 1.1 to 1.12.
7
8
(6)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to TIA-968-A figures 1.1 to 1.12.
9
10
11
12
13
14
15
Figure 9.38-1. Voiceband Signal Power - Non-approved external signal sources
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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
10 TRANSVERSE BALANCE LIMITATIONS TIA-968 Par 4.6
10.1 Transverse Balance, Analog TIA-968-A Par 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" (FCC Part 68.3 - Definition of
harm). Therefore crosstalk must be 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
28
29
30
31
32
33
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.
Transverse Balance tests are applicable to the on-hook and off-hook states of one-port 2wire 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.
34
35
36
37
10.1.2 Purpose
38
39
10.1.3 Equipment
To determine the transverse balance of the EUT in its various operating modes.
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(1)
Applicable loop simulator SEL# 4 (see comment 6).
2
(2)
Frequency generator SEL# 27.
3
(3)
Frequency selective voltmeter SEL# 28 or spectrum analyzer SEL# 34.
4
(4)
Transverse balance bridge SEL# 30.
5
6
NOTE: Refer to Section 5.3 for equipment details.
7
8
9
10.1.4 Equipment States Subject To Test
(1)
Power on:
10
(a)
On-hook (idle), when applicable.
11
(b)
Off-hook (quiet state).
12
(2)
Power off:
13
(a)
On-hook (idle), when applicable.
14
(b)
Off-hook (quiet state), if feasible with power off.
15
(3)
Power fail (if different than power off):
16
(a)
On-hook (idle), when applicable.
17
(b)
Off-hook (quiet state), if feasible with power fail.
18
19
20
21
22
23
24
25
26
27
28
29
30
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 shall 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 shall be
connected to the test ground plane. Equipment which does not
contain any of these potential connections to ground shall be placed
on a conductive plate which is connected to the test ground plane
(see comment 2); this applies to both non-powered and ac-powered
equipment.
31
32
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 V rms (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
(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).
The result of this balance calibration must be at least 20 dB greater than the balance
requirement for the EUT at that frequency specified in TIA-968 clause 4.6.2.
15
(6)
Substitute the EUT for the 600 ohm resistor. For multiport EUT, see comment 1.
16
17
18
(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).
19
20
(8)
Return the loop simulator to the condition resulting in the worst case balance noted
in step (7).
21
22
(9)
Measure the voltage across the tip and ring of the EUT; this is the metallic reference
voltage (VM).
23
24
(10)
Measure the voltage across the 500 ohm resistor; this is the longitudinal voltage
(VL).
25
(11)
Calculate the balance using the following formula:
TransverseBalance 20logV M
26
27
28
29
30
31
32
33
34
V
L
NOTE: If the readings are, for example, taken in dBV, then the equation may be
simplified to:
Balance ( dB )  V
(12)
M
( dBV )  V L ( dBV )
Reverse the tip and ring connections of the EUT and repeat step (9) to step (11).
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The lesser of the two results is the transverse balance of the EUT at 200 Hz.
2
3
4
5
(12)
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
(13)
Repeat step (2) through step (13) for all applicable equipment states.
7
8
9
10
11
10.1.6 Alternative Methods
12
13
14
10.1.7 Suggested Test Data
(1)
Frequencies tested.
15
(2)
Balance measured of the frequencies tested.
16
(3)
EUT and loop simulator condition for each measurement.
See Appendix D.
17
18
19
20
21
22
23
24
25
10.1.8 Comments
26
27
28
29
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.
30
31
3) Interference from power frequency harmonics can be minimized by using test
frequencies midway between multiples of 60 Hz.
32
33
4) In some cases, the EUT may apply internally generated signals to the test set. Such
signals should not be construed as part of the transverse balance test.
1) For multiport EUTs, input leads of ports not under test should be properly terminated
by connecting the terminating network shown in TIA-968, 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. The dc portion of the loop simulator shall be included during the
calibration process.
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2
5) If a frequency selective voltmeter or spectrum analyzer are not available, transverse
balance measurements may be made if:
3
4
(a)
The environment is relatively free from electromagnetic interference in the
voiceband; and
5
(b)
The EUT generates very low in-band noise.
6
7
8
(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.
9
10
6) To achieve an acceptable degree of calibration balance, the use of batteries in the loop
simulator circuit is recommended.
11
12
7) A dc current meter may be included as part of the loop simulator circuit in order to
monitor loop conditions.
13
14
15
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.
16
17
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2
T1
C1, C2
C3, C4
Osc
R1
RL
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
600 : 600  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 
Selected such that ZOSC + R1 = 600 
500 
NOTES:
1. VM shall not be measured at the same time as VL.
2. The test circuit shall be balanced to 20 dB greater than the equipment standard for
all frequencies specified (using trimmer capacitors C3 and C4), with a 600 
resistor substituted for the equipment under test.
3. Exposed conductive surfaces on the exterior of the equipment under test shall be
connected to the ground plane for this test.
When the Terminal Equipment makes provision for an external connection to
ground, the Terminal Equipment shall be connected to ground. When the Terminal
Equipment makes no provision for an external ground, the Terminal Equipment
shall 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 shall be centrally located on the
ground plane without any additional connection to ground.
Figure 10.1-1 Transverse Balance, Analog
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2
10.2 Transverse Balance, Digital TIA-968-A Pars 4.6.3, 4.6.4
3
4
5
6
10.2.1 Background
See Section 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.
15
16
NOTE: Refer to Section 5.3 for equipment details.
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
10.2.4 Equipment States Subject To Test
32
33
34
35
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.
36
37
(2)
Set the spectrum analyzer and tracking generator to the appropriate frequency
ranges:
To determine transverse balance of digital EUT.
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 shall 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 shall be connected to the test ground plane. Equipment which
does not contain any of these potential connections to ground shall 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.
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(a)
For 2.4 kb/s subrate EUT - 200 Hz to 2.4 kHz
2
(b)
For 3.2 kb/s subrate EUT - 200 Hz to 3.2 kHz
3
(c)
For 4.8 kb/s subrate EUT - 200 Hz to 4.8 kHz
4
(d)
For 6.4 kb/s subrate EUT - 200 Hz to 6.4 kHz
5
(e)
For 9.6 kb/s subrate EUT - 200 Hz to 9.6 kHz
6
(f)
For 12.8 kb/s subrate EUT - 200 Hz to 12.8 kHz
7
(g)
For 19.2 kb/s subrate EUT - 200 Hz to 19.2 kHz
8
(h)
For 25.6 kb/s subrate EUT - 200 Hz to 25.6 kHz
9
(i)
For 38.4 kb/s subrate EUT - 200 Hz to 38.4 kHz
10
(j)
For 51.2 kb/s subrate EUT - 200 Hz to 51.2 kHz
11
(k)
For 56.0 kb/s subrate EUT - 200 Hz to 56.0 kHz
12
(l)
For 72.0 kb/s subrate EUT - 200 Hz to 72.0 kHz
13
(m)
For BRA EUT - 200 Hz to 192 kHz
14
(n)
For DS1 (1.544 Mb/s) EUT - 12 kHz to 1.544 MHz
15
(o)
ADSL EUT – 13.6 kHz to 1.625 MHz (see comment 6)
16
17
18
(3)
Adjust the tracking generator voltage to measure a VM of 0.367 Vrms across the
calibration test resistor of 135 ohm or 0.316 Vrms across the calibration test resistor
of 100 ohm as appropriate.
19
20
(4)
Connect the spectrum analyzer across the RL resistor (90 or 500 Ohms as per TIA968-A, Table 4.12).
21
22
23
24
25
26
(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 shall 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
construction.
27
28
29
30
31
(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
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(5) above.
2
3
(7)
Replace the calibration resistor with one tip-and-ring pair of the EUT (see comment
4).
4
5
(8)
Measure the voltage across the tip and ring of the EUT; this is the metallic reference
voltage (VM).
6
(9)
Measure the voltage across the RL resistor; this is the longitudinal voltage (VL).
7
(10)
Calculate the balance using the following formula:
TransverseBalance 20logV M
8
9
10
11
12
13
14
15
16
V
L
NOTE: If the readings are, for example, taken in dBV, then the equation may be
simplified to:
Balance ( dB )  V
M
( dBV )  V L ( dBV )
(11)
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.
17
18
(12)
If applicable, Connect the other tip and ring pair of the EUT to the balance test set
(see comment 4).
19
(13)
Repeat step (8) through step (11) for this pair.
20
21
22
23
10.2.6 Alternative Methods
24
25
26
10.2.7 Suggested Test Data
(1)
EUT tip and ring pair tested.
27
(2)
Frequencies tested.
28
(3)
Balance measured for the pair.
29
(4)
Calibration balance measured.
30
31
10.2.8 Comments
See Appendix D.
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2
3
4
(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.
5
6
(2)
Interference from power frequency harmonics can be minimized by using test
frequencies midway between multiples of 60 Hz.
7
8
(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.
9
10
(4)
Some digital equipment referenced in this section has a transmit pair and a receive
pair. Balance measurements should be performed on both pairs.
11
12
13
(5)
Test leads between the test fixture and the EUT will affect the calibration and EUT
balance measurements. Such cables must be in place when making the calibration
balance adjustments.
14
15
16
17
(6)
Alternatively, a narrower frequency range may be used for 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.
18
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2
100/135 :100/135  wide-band transformer
(100 for 1.544 Mbps or ADSLdevices and 135  for sub-rate or BRA devices.)
Optimally a dual-stator air-variable RF capacitor that maintains a constant
20 pF
capacitance between stators while providing a variable capacitance from either
Differential
stator to ground.
3 pF
Composition RF capacitor
RCAL
100/135  (See Note 2)
90/500 : A non-inductive precision resistor
RL
(chosen according to Table 4.12).
T1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
NOTES:
a) The 3 pF capacitor may be placed on either line of the test set, as required, to obtain
proper balancing of the bridge.
b) Use an RCAL value of 100  for 1.544 Mbps or ADSL devices and 135  for sub-rate
or BRA devices.
c) The effective output impedance of the tracking generator shall match the appropriate
test impedance. See Note 2. The spectrum analyzer's input shall be differentially
balanced to measure VM.
d) The impedance of the Tracking Generator shall be chosen to match the Metallic
Termination (RM) according to TIA-968-A, Table 4.12.
e) The transformer should be a wide band transformer with a 1:1 impedance ratio.
Figure 10.2-1 Transverse Balance, Digital
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2
3
11 ON HOOK IMPEDANCE LIMITATIONS TIA-968 Par 4.7
11.1 DC Resistance TIA-968 Pars 4.7.2.1 and 4.7.2.2
4
5
6
7
8
9
10
11
12
13
14
15
11.1.1 Background
16
17
11.1.2 Purpose
18
To measure the dc resistance of the EUT during its idle, or on-hook state.
19
20
21
11.1.3 Equipment
(1)
DC current meter SEL# 19 or 20.
22
(2)
DC power suply SEL# 21.
23
(3)
DC voltmeter SEL# 22.
24
NOTE: Refer to Section 5.3 for equipment details.
25
26
27
28
11.1.4 Equipment States Subject To Test
29
30
31
11.1.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 11.1-1.
32
(2)
Set the voltage to 1 V dc and allow the circuit to stabilise.
33
34
(3)
Slowly increase the voltage to 100 volts and observe the current as the voltage is
increased.
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 megaOhms. (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 must be greater than 30 kiloOhms.
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.
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2
3
(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.
4
5
(5)
If the current increases suddenly at any point, record the voltage and current at
these points. Calculate the dc resistance at these points.
6
7
8
(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.
9
10
(7)
Slowly increase the voltage from 100 to 200 volts and observe the current as the
voltage is increased.
11
12
13
(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.
14
15
(9)
If the current increases suddenly at any point, record the voltage and current at
these points.
16
17
(10)
In addition to any points recorded in step (7), measure and record the current at
voltages of 100, 150, and 200 volts.
18
(11)
Reverse the polarity of the test circuit and repeat steps (2) through (10).
19
(12)
Connect the EUT to the test circuit of figure 11.1-2.
20
21
(13)
Repeat steps (2) through step (10) with connections made to the tip and ground
leads of the EUT.
22
23
(14)
Repeat Steps (2) through (10) with connections made to the ring and ground leads
of the EUT.
24
25
26
27
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
11.1.8 Comments
9
(1)
The internal resistances of all measuring equipment is to be taken into account.
10
11
(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
6
7
8
NOTE:
The 1 kOhm resistor is provided as a current limiter.
Figure 11.1-2. DC Resistance, T-GND & R-GND
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11.2 DC Current During Ringing TIA-968-A Pars 4.7.2.3 and 4.7.3.1
2
3
(1)
4.7.2.3 for Loop-Start
4
(2)
4.7.3.1 for Ground-Start
5
6
7
8
9
10
11
12
13
14
11.2.1 Background
15
16
17
18
11.2.2 Purpose
19
20
21
11.2.3 Equipment
(1)
AC Volt Meter SEL# 3.
22
(2)
DC current meter SEL# 19.
23
(3)
DC power supply SEL# 21.
24
(4)
Frequency generator SEL# 27.
25
(5)
Ringing amplifier SEL# 33.
26
27
NOTE: Refer to Section 5.3 for equipment details.
28
29
30
31
32
11.2.4 Equipment States Subject To Test
33
34
11.2.5 Procedure
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.
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.
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(1)
Connect the EUT to the test circuit of Figure 11.2-1.
2
3
(2)
Set the test equipment to supply the lowest frequency and voltage listed in Table
4.13 of Section 4.7for the ringing type being tested.
4
(3)
Record the dc current.
5
6
(4)
Increase the ringing voltage to the maximum for the chosen ringer type from Table
4.13 of Section 4.7.
7
(5)
Record the dc current.
8
9
(6)
Repeat step (3) through step (5) for the other recommended frequencies (See
comment (1)).
10
11
(7)
Reverse the connections of the EUT to the test circuit and repeat step (2) through
step (6).
12
13
14
11.2.6 Alternative Methods
15
16
17
18
11.2.7 Suggested Test Data
19
20
21
22
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.
23
24
(2)
The internal characteristics (impedances) of all monitoring equipment must be taken
into account.
25
26
27
28
29
(3)
If the EUT derives operating power or power assist from the incoming ringing
signal, it may be damaged by the continuously applied ringing as described in this
section. 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.
None suggested.
The dc current at each of the ac voltage levels and frequencies.
30
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2
3
4
5
6
7
8
9
10
Figure 11.2-1. DC Current During Ringing
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2
11.3 AC Impedance During ringing (Metallic and Longitudinal) TIA-968-A Pars
4.7.2.4, 4.7.2.5, and 4.7.3.2
3
4
(1)
4.7.2.4 for Loop-Start
5
(2)
4.7.2.5 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
28
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 Section 5.3 for equipment details.
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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 Section 4.7for 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 Section 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
(1)
The current at the various ac voltage levels and frequencies.
29
(2)
Calculated ac impedances.
30
11.3.8 Comments
None suggested.
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2
3
(1)
For “A” type ringers, measure at 20 and 30 Hz. For "B" ringers, measure at 15.3, 20,
35, 50, and 68 Hz.
4
5
(2)
The internal characteristics (impedances) of all monitoring equipment must be taken
into account.
6
7
8
9
(3)
If the EUT derives operating power or power assist from the incoming ring, it
may
be damaged by the continuously applied ringing as described in this section. 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.
10
11
(4)
When testing series connected devices, remove all terminations from the nonnetwork side of the EUT as they could adversely affect the measurement.
12
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2
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4
5
6
7
8
9
10
11
12
Figure 11.3-1. AC Impedance, T-R
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2
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4
5
6
7
8
Figure 11.3-2. AC Impedance, T-GND & R-GND
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11.4 REN Calculation TIA-968-A Pars 4.7.4 and 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
11.4.4 Equipment States Subject To Test
22
Not applicable.
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
35
36
37
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.
Refer to Section 4.7.4 for computation of REN. Use data obtained in Section 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
equipment intended for connection to loop start facilities":
(1)
AC data derived from Section 11.3.5 is converted to REN numbers as described in
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3
Section 4.7.4 for tests at 16 Hz and 68 Hz, and Section 4.7, Table 4.13, ringing type
B:
(2)
Assume at 150 V rms, 12.3 mA ac is measured at 68 Hz.
4
5
6
7
8
9
10
11
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 Section 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:
12
13
14
15
16
17
18
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.
19
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2
11.5 OPS Ring Trip, PBX with DID TIA-968-A Par 4.7.6
3
4
5
6
7
8
9
10
11
11.5.1 Background
12
13
11.5.2 Purpose
14
15
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.
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 Section 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
33
34
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.
None.
The PBX equipment is to be tested while it is ringing an off-premise station.
None suggested.
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.
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3
4
11.5.8 Comments
None.
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3
4
5
6
7
8
NOTE:
The value of R and C are calculated in accordance with Section 4.7.6.
Figure 11.5-1. OPS Ring Trip
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11.6 Transitioning to the Off-Hook State and Make-busy TIA-968-A Par 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
36
37
11.6.8 Comments
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 Section 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 TIA 968-A, Section 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
This section 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 shall be
considered telephone connections and comply with the requirements of TIA-968-A,
Sections 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 shall comply with all of TIA968-A when the MB and MB1 leads are bridged to the tip and ring connections.
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4
5
6
7
11.7 Manual programming of Repertory Numbers, 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
35
36
37
11.7.8 Comments
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 Section 5.3 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.
This requirement is applicable to all EUT that provides memory or automatic dialing.
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2
3
4
5
6
Notes:
(1) Select the appropriate loop simulator for the interface of the EUT. Refer to the figures
of Section 1 of TIA-968-A.
7
(2)
8
9
10
11
12
13
14
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 stutter dial tone detection TIA-968-A Par 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
23
11.8.4 Equipment States Subject To Test
24
25
26
27
28
29
11.8.5 Procedure
To verify the characteristics of the EUT automatic off-hook checks for stutter dial tone
detection.
Test when the EUT makes a stutter dial tone check.
1. Consult the EUT manual to determine if the equipment performs automatic stutter
dial tone detection. Equipment that does not support this function meets the
requirements of this section without further test. Equipment supporting this function
must pass the conditions of steps (2) through (8).
30
2. Connect the EUT to the test circuit of Figure ?.
31
32
33
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.
34
4. By Simulate an unanswered incoming calling event. Monitor and record the number
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2
3
4
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.
5
6
7
8
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.
9
10
11
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.
12
7. The responsible party shall attest to section 4.7.8.2 a), f) and g) of TIA-968-A.
13
14
15
11.8.6 Alternate Methods
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
11.8.7 Suggested Test Data
35
36
37
38
11.8.8 Comments
None.
1. Number of stuttered dial tone checks after the completion of a calling event.
2. Time interval from the completion of a calling event to the completion of the
stuttered dial tone check.
3. Number of stuttered dial tone checks after the completion of an unanswered
incoming calling event.
4. Number of stuttered dial tone checks after the completion of an unanswered
incoming calling event attempted while the visual message indicator is lit.
5. Duration of the stuttered dial tone check after dial tone application when dial tone
is applied within three seconds.
6. Duration of the stuttered dial tone check with no dial tone applied within three
seconds.
(1)
The suggested level for application of dial tone is -13 dBm. This corresponds with
specified network levels.
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(2)
Dial tone is specified in T1.401-2000 (Ref A?).
2
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2
3
4
12 BILLING PROTECTION TIA-968-A Par 4.8
5
6
12.1.1 Background
12.1 Call Duration for Data Equipment, Protective Circuitry TIA-968-A Par 4.8.1.1
7
8
9
10
11
12
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.
13
14
15
16
12.1.2 Purpose
17
18
19
12.1.3 Equipment
(1)
Applicable loop simulator SEL# 4.
20
(2)
Bandpass filter SEL# 12.
21
(3)
Digital sampling storage oscilloscope SEL# 24.
22
(4)
Frequency generator SEL# 27.
23
(5)
Ringing amplifier SEL# 33.
24
25
26
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 Section 5.3 for equipment details.
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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 s 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
30
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
state in both directions of transmission.
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(2)
Verification of data delay.
2
3
4
12.1.8 Comments
(1)
Actual data signals may be used in place of the signal generator.
5
(2)
Test frequencies other than 1000 Hz may be used.
6
7
(3)
The signal level measured in Step (12) should be no greater than the signal level in
Step (8).
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
NOTES:
(1) Select the appropriate loop simulator for the interface of the EUT.
(2) Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 68.3 of Part 68.
(3) Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 68.3 of Part 68.
Figure 12.1-1. Call Duration, PC, Transmit
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2
3
4
5
6
7
NOTES:
(1) Select the appropriate loop simulator for the interface of the EUT.
8
9
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 68.3 of Part 68.
10
11
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 68.3 of Part 68.
12
13
14
15
Figure 12.1-2. Call Duration, PC, Receive
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2
12.2 Call Duration for Data Applications, Terminal Equipment TIA-968-A Par
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
12.2.2 Purpose
11
12
To verify that the data equipment does not transmit or receive data for the first two
seconds after answering an incoming call.
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.
19
20
NOTE: Refer to Section 5.3 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.
31
(3)
Apply the ringing signal to the EUT.
32
33
34
(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
Answering an incoming call, transmitting and receiving data (on-hook to off -hook
transition).
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required time, verify that it is one of the allowed signals.
2
(5)
Connect the EUT to the test circuit of Figure 12.2-2.
3
(6)
Set the EUT to receive data.
4
5
(7)
Set the oscilloscope to trigger on the transition from the on-hook to the off-hook state
of the EUT.
6
(8)
Apply the ringing signal to the EUT.
7
8
(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).
9
10
12.2.6 Alternative Methods
11
12
None suggested.
13
14
12.2.7 Suggested Test Data
15
16
Verification of the data delay.
17
18
12.2.8 Comments
19
20
21
22
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
NOTE: 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.
Figure 12.2-1. Call Duration, EUT, Transmit
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2
3
4
5
6
7
8
9
10
NOTE: 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.
Figure 12.2-2. Call Duration, EUT, Receive
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12.3 On-hook Signal Power, Analog TIA-968-A Par 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
16
NOTE: Refer to Section 5.3 for equipment details.
17
18
19
12.3.4 Equipment States Subject to Test
20
12.3.5 Procedure
21
22
12.3.5.1
23
24
(1)
Connect the EUT to the test circuit of Figure 12.3-1 using the 200-Hz-to-4000-Hz
bandpass filter and voltmeter.
25
(2)
Place the EUT in the on-hook state.
26
(3)
Measure and record the maximum signal power level in dBm.
27
(4)
Verify that the signal level is less than the limit.
28
29
30
12.3.5.2
On-hook state.
(1)
For Terminal Equipment:
For Protective Circuits:
Connect the EUT to the test circuit of Figure 12.3-2.
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(2)
Place the EUT in its on-hook state.
2
3
(3)
Adjust the input signal to the EUT to 1000 Hz at a level at least 10 dB above the
overload point.
4
(4)
Measure and record the output signal power level in dBm.
5
12.3.6 Alternate Methods
6
7
8
9
12.3.6.1
10
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).
(2)
Set the signal analyzer to measure the following:
11
(m) Signal level in dBm, 600 ohms.
12
(n)
Averaging over 3 second.
13
(o)
Band pass power in the frequency range of 200 Hz to 4000 Hz band.
14
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
NOTES:
(1) Select the appropriate loop simulator for the interface of the EUT.
5
6
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
7
8
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section .
9
10
11
12
13
Figure 12.3-1. On-hook Signal Power, TE
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2
3
4
5
NOTES:
(1) Select the appropriate loop simulator for the interface of the EUT.
6
7
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
8
9
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section .
10
(4)
The frequency generator is only required for testing protective circuitry.
11
12
13
14
15
16
17
Figure 12.3-2. On-hook Signal Power, PC
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12.4 Off-Hook Loop Current TIA-968-A Par 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 Section 5.3 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
3
4
12.4.5 Procedure
5
6
7
12.4.5.1
(1)
Connect the EUT to the test circuit of Figure 12.4-1.
8
(2)
Set the dc voltage of the loop simulator to 42.5 V dc.
9
(3)
Set switch S1 to position "A”.
10
11
(4)
Adjust resistor R2 of the loop simulator to 1740 Ohms and record the loop current
through the 200 Ohm resistor.
12
(5)
Set switch S1 to position "B”.
13
(6)
Cause the EUT to go off-hook.
14
15
(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.
16
17
(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.
NOTE: Either of the two following methods can be used:
Method A: Comparison With Current through a 200-Ohm Resistor
18
19
20
21
12.4.5.2
Method B: Percent Change in dc Current
(1)
Connect the EUT to the test circuit of Figure 12.4-2.
22
23
(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).
24
(3)
Place the EUT in its on-hook state.
25
(4)
Set the oscilloscope to trigger on the transition from on-hook to off-hook of the EUT.
26
(5)
Cause the EUT to go off-hook.
27
28
29
(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
minimum voltage levels.
30
(7)
The percent change in current will be equal to the percent change in voltage of the
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minimum voltage level relative to the maximum voltage during the first five seconds.
2
3
(8)
Set R2 set to its minimum value and adjust the source voltage to its maximum value
(400 Ohms, 56.5 V dc).
4
(9)
Repeat Step (3) through Step (7).
5
6
(10)
Set R2 to a value that produces a mid-range current and adjust the source voltage
to its maximum value (1200 Ohms, 52.5V).
7
(11)
Repeat Step (3) through Step (7).
8
9
10
12.4.6 Alternative Methods
11
12
12.4.7 Suggested Test Data
13
14
15
12.4.7.1
(1)
Loop current measured with 200-ohm resistor (mA dc).
16
(2)
Loop current measured with EUT (mA dc).
17
(3)
Comparison of loop currents.
18
(4)
Resistor R2 range.
19
20
21
12.4.7.2
(1)
Maximum and minimum off-hook dc voltage during the first five seconds.
22
(2)
Percent change during first five seconds.
23
(3)
Resistor R2 range.
24
25
26
12.4.8 Comments
(1)
Chart recorder can be used in place of oscilloscope.
27
28
(2)
A dc current probe may be used with the oscilloscope to monitor current instead of
voltage.
None suggested.
Method A: Comparison with 200 Ohm Resistor
Method B: Percent Change in Loop Current
29
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2
3
4
5
6
7
8
9
10
11
12
13
NOTE:
(1)
Only the dc portion of the loop simulator circuit should be connected for this test.
(2)
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the Figure 1.1 of Section 1 of TIA-968-A.
Figure 12.4-1. Loop Current, 200 ohm Method
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2
3
4
5
6
7
8
NOTE: Only the dc portion of the loop simulator circuit should be connected for this test.
Figure 12.4-2. Loop Current, 25% Method
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2
12.5 Signaling Interference, Analog TIA-968-A Par 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.
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 A13).
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.
25
26
27
NOTE: Refer to Section 5.3 for equipment details.
28
29
30
31
12.5.4 Equipment States Subject to Test
32
33
34
12.5.5 Procedure
Test the first two seconds after the EUT goes off-hook in response to receiving an
alerting signal.
(1)
Connect the EUT to the test circuit of Figure 12.5-1.
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(2)
Select the bandpass filter for the 800 Hz-to-2450 Hz band.
2
(3)
Initiate a call into the EUT.
3
4
(4)
Measure the maximum signal power in dBm after the EUT goes off-hook for the
first two seconds.
5
(5)
Return the EUT to its on-hook state.
6
(6)
Select the bandpass filter for the 2450 Hz-to-2750 Hz band.
7
(7)
Initiate a call into the EUT.
8
9
(8)
Measure the maximum signal power in dBm after the EUT goes off-hook for the
first two seconds.
10
11
(9)
Compare the energy in the 2450 Hz to 2750 Hz band to the energy in the 800 Hz to
2450 Hz band.
12
(10)
Repeat Step (2) through Step (9) for all other call answering modes, if applicable.
13
14
15
16
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).
17
(2)
Set the signal analyzer to measure the following:
18
(p)
Signal level in dBm, 600 ohms.
19
(q)
Averaging over 2 second.
20
(r)
Band pass power in the frequency range of 800 Hz to 2450 Hz band.
21
22
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
23
(3)
Initiate a call into the EUT.
24
25
(4)
Measure the maximum signal power in dBm after the EUT goes off-hook for the first
two seconds.
26
(5)
Return the EUT to its on-hook state.
27
28
(6)
Set the band pass power of the Signal Analyzer to the frequency range of 2450 Hz to
2750 Hz band.
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(7)
Initiate a call into the EUT.
2
3
(8)
Measure the maximum signal power in dBm after the EUT goes off-hook for the first
two seconds.
4
5
(9)
Compare the energy in the 2450 Hz to 2750 Hz band to the energy in the 800 Hz to
2450 Hz band.
6
(10) Repeat Step (3) through Step (9) for all other call answering modes, if applicable.
7
8
9
10
12.5.7 Suggested Test Data
(1)
800-Hz-to-2450-Hz band energy.
11
(2)
2450-Hz-to-2750-Hz band energy.
12
(3)
Signal power levels in dBm.
13
14
15
16
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.
17
18
(2)
A voltmeter or signal analyzer that can be triggered by the on-hook to off-hook
transition is helpful.
19
20
(3)
Refer to Section 4.8.1 of TIA-968-A for conditions where data equipment is exempt
from this requirement.
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2
3
4
5
6
NOTES:
(1)
Select the appropriate loop simulator for the interface of the EUT.
7
8
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 1 of TIA-968-A.
9
10
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 1 of TIA-968-A.
11
12
13
14
15
16
17
18
Figure 12.5-1. Signaling Interference
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12.6 Signalling Interference, Digital TIA-968-A Par 4.8.4.2
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3
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6
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9
10
12.6.1 Background
11
12
13
14
15
12.6.2 Purpose
16
17
18
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
32
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 section apply to the called station during the first two seconds
of connection. See also FCC Public Notice 9160 (Ref A13).
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 Section 5.3 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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2
3
4
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
10
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
17
18
12.6.6 Alternative Methods
(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).
19
(2)
Set the signal analyzer to measure the following:
20
(s)
Signal level in dBm, 600 ohms.
21
(t)
Averaging over 2 second.
22
(u)
Band pass power in the frequency range of 800 Hz to 2450 Hz band.
23
24
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
25
26
27
(11) 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.
28
29
(12) Measure the maximum signal power in dBm after the EUT goes off-hook for the first
two seconds.
30
(13) Read the signal energy in the 800-Hz-to-2450-Hz band.
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2
(14) Set the band pass power of the Signal Analyzer to the frequency range of 2450 Hz to
2750 Hz band.
3
(15) Read the signal energy in the 2450-Hz-to-2750-Hz band.
4
(16) Repeat Step (3) through Step (7) for all other call answering modes, if applicable.
5
6
7
8
12.6.7 Suggested Test Data
(1)
The signal which was measured.
9
(2)
The signal power contained in the band from 800-Hz-to-2450-Hz.
10
(3)
The signal power contained in the band from 2450-Hz-to-2750-Hz.
11
12
13
14
12.6.8 Comments
(1)
A 600-Ohm termination should be applied at the input of the filter, and the voltmeter
should be unterminated.
15
16
(2)
Simultaneous measurement of the signal power contained in each band
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 TIA-968-A Pars 4.8.5
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5
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9
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11
12
12.7.1 Background
13
14
15
16
17
12.7.2 Purpose
18
19
20
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.
24
25
26
NOTE: Refer to Section 5.3 for equipment details.
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.
27
28
29
30
12.7.4 Equipment States Subject to Test
31
32
33
12.7.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.7-1.
34
(2)
Cause the digital equipment to transmit the on-hook signal.
35
(3)
Measure the signal power as derived at the output of the zero-level decoder or
The EUT is to be in the on-hook state and transmitting the on-hook digital signal.
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2
companion terminal equipment.
3
4
5
6
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).
7
(2)
Set the signal analyzer to measure the following:
8
(v)
Signal level in dBm, 600 ohms.
9
(w) Averaging over 3 second.
10
(x)
Band pass power in the frequency range of 200 Hz to 4000 Hz band.
11
12
Note: Signal Analyzer should provide a balanced input, or an isolation transformer
may be used.
13
14
15
(3)
Place the EUT in the on-hook state and measure and record the maximum signal
power level.
16
17
18
12.7.7 1.544 Mb/s Protective Circuits
(5)
Connect the EUT to the test circuit of Figure 12.7-1
19
(6)
Place the EUT in its on-hook state.
20
21
(7)
Provided an 1000 Hz input signal to the EUT at a level at least 10 dB above the
overload point.
22
23
(4)
Measure and record the output signal power level in dBm.
24
25
26
27
12.7.8 Suggested Test Data
28
29
30
31
32
33
12.7.9 Comments
The measured on-hook signal level in dBm with respect to 600 Ohms.
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
5
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7
8
9
Figure 12.7-1. Subrate and 1.544 Mb/s, On-hook Level
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12.8 Signalling duration, 1.544 Mb/s TIA-968-A Par 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
20
21
NOTE: Refer to Section 5.3 for equipment details.
22
23
24
12.8.4 Equipment States Subject to Test
25
26
27
12.8.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.8-1.
28
(2)
Apply incoming alerting signaling to the input of the EUT.
29
30
31
(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.
32
(4)
Immediately remove the alerting signal.
33
34
(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
Place the device in the off-hook state in response to the alerting signal.
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3
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.
4
5
6
12.8.6 Alternative Methods
7
8
9
12.8.7 Suggested Test Data
10
11
12
13
None suggested.
State whether the digital equipment complies with this requirement.
12.8.8 Comments
This test applies only to channelized 1.544-Mb/s digital equipment.
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8
9
Figure 12.8-1. 1.544 Mb/s, Signaling Duration
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12.9 Operating Requirements for DID 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.
8
9
10
12.9.2 Purpose
11
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
25
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
31
(4)
Connect channel 1 of the storage oscilloscope (between ring lead and ground) to the
EUT.
32
(5)
Connect channel 2 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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called station under test.
2
(6)
Originate a direct inward dialing call from the companion terminal equipment.
3
(7)
Monitor the EUT line loop polarity with the digital DC voltmeter.
4
5
6
(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.
7
8
(9)
Ensure that the line reversed answer supervision state maintains for the duration of
the call.
9
10
11
(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).
12
13
14
12.9.5.2
(1)
Connect the TE to the test circuit of Figure 12.9.5.2-1.
15
16
(2)
Activate the A&B bits on the Zero Level encoder to simulate an incoming call on the
Reverse Battery DSO Channel under test.
17
18
(3)
Monitor the A&B bits transmitted by the TE and the Tip and Ring leads of the called
station.
19
20
21
(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.
22
23
(5)
Ensure that the A&B bit status remains in the answer supervision mode for the
duration of the call.
24
25
26
(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
27
28
29
30
12.9.6 Alternative Methods
31
32
33
12.9.7 Suggested Test Data
None suggested.
State whether the TE complies with this requirement.
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7
8
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12.9.8 Comments
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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8
9
NOTES:
(1)
10
11
12
13
14
15
16
17
18
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 Mb/s Direct Inward Dialing
12.9.9
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13 MINIATURE PLUGS AND JACKS, 6 and 8 POSITION TIA-968-A Par 6
13.1 Gold Contact Interface
13.1.1 Background
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
also permits the use of non-gold interface materials so long as they are compatible with
each other and with gold, and of equivalent performance to gold.
Note (1) to Figure 68.500(a)(3)(i) states:
"The plug/jack contact interface should be hard gold to hard gold and should
have a minimum gold thickness of 0.000050 inch on each side of the interface.
The minimum contact force should be 100 grams. . . . A smooth, burr-free
surface is required at the interface in the area shown."
An industry committee (established at the request of the FCC) provided the FCC with
the following interpretation of the above Part 68 requirement:
A contact interface that uses gold as the principal contact interface material should meet
the following plating, material and test requirements:
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(1) Gold Plate
Per MIL-G-45204C:( Ref A18)
Type II (99% Pure Gold Minimum),Grade
C+ (Knoop Hardness Range 130-250),
Class 1 (50 inches minimum thickness).
(2) Gold Plate Density
17 grams/cubic centimeter minimum.
(3) Plating Porosity
Test per EIA-364-53 Nitric Acid.
Vapor Test (Ref A8).
(4) Surface Finish
Surface roughness to be 32 inches maximum
finish as determined by comparing contact surface
with a 32-inch, ground-surface-finish gauge at
10X magnification.
50 inches minimum thickness Plate (between
ductile nickel (matte finish plating).
to be 99.5% nickel minimum and no other single
component to be more than 0.2%. Plating should
not crack when bent through a 180o angle, with the
coated surface away, around a mandrel whose
diameter is equal to the thickness or diameter of
the contact sample).
(5) Nickel Barrier Plate
(Between Gold and Base
metal)
2
3
4
5
6
7
8
9
10
11
12
This gold contact interface definition 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 the above specification
for material quality, thickness, density, porosity and surface roughness are to be
considered the same as an acceptable plated interface.
13
14
15
16
13.1.2 Purpose
17
18
13.1.3 Equipment
This test verifies that a contact interface which uses gold as the principal material
satisfies the conditions in Section 16.1.1.
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(1)
X-ray fluorescence tester (ASTM B568) (Ref A2).
2
(2)
Atomic absorption tester.
3
(3)
Knoop hardness tester (ASTM E384) ( Ref A1).
4
(4)
Standard chemical reagents and lab equipment per EIA-364-53 (Ref A8).
5
(5)
Ground surface roughness gauge.
6
(6)
10X magnifier.
7
NOTE: Section 5.3 does not list this equipment.
8
9
10
13.1.4 Equipment States Subject to Test
11
12
13
13.1.5 Procedure
(1)
Measure material thickness using X-Ray fluorescence tester.
14
(2)
Measure plating composition with the atomic absorption tester.
15
(3)
Measure plating hardness using the Knoop hardness tester.
16
17
(4)
Measure plating porosity using chemical reagents and laboratory equipment
procedures from EIA-364-53 (Ref A8).
18
19
(5)
Make a visual comparison at 10X magnification between a ground surface
roughness gauge (32 inches) and the surface to be examined.
20
21
22
13.1.6 Alternative Methods
23
24
25
13.1.7 Suggested Test Data
(1)
Material thickness.
26
(2)
Plating composition.
27
(3)
Plating hardness.
28
(4)
Plating porosity.
Not applicable.
None suggested.
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(5)
Observations from visual comparison.
2
3
4
5
6
13.1.8 Comments
None.
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13.2 Non-gold Contact Interface
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
13.2.1 Background
20
21
22
23
24
13.2.2 Purpose
25
26
27
13.2.3 Equipment
(1)
Current meter as described in IEC 512-2, Test 2a. (Ref A14).
28
(2)
Force gauge, 0 to 2 kg, 0.05 kg resolution minimum.
29
30
(3)
Durability test equipment as described in EIA-364-09A (Ref A6) (see also
(1)).
31
32
(4)
Temperature/Humidity Chamber capable of achieving a temperature range of -40 oF
(-40 oC) to 150 oF (65.6 oC) and a humidity range of up to 95% relative humidity.
33
34
35
36
37
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
also permits the use of non-gold interface materials so long as they are compatible with
each other and with gold, and of equivalent performance to gold.
Note (1) to Figure 68.500(a)(3)(i) states:
" . . Any non-gold contact material must be compatible with gold and provide
equivalent contact performance. A smooth, burr-free surface is required at the
interface in the area shown."
The following procedures were developed for non-gold contact interface materials at the
request of the FCC.
To show equivalency of non-gold contact interface materials with gold contact interface
materials, as defined in Section 15.1. It is intended for evaluation of connectors that
have applications under Part 68.
NOTE: Section 5.3 does not list this equipment.
13.2.4 Equipment States Subject to Test
Not applicable.
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13.2.5 Procedure
(1)
Figure 13.2-1 outlines a sequence of four independent paths of tests which should
be performed. All results are of a pass/fail nature.
5
(2)
Select and qualify connector samples (See comment (2)).
6
(3)
Mating and unmating forces.
7
8
9
10
11
Mating and unmating of the plug and jack should be at a rate of 0.4 inch/s (10 mm/s)
(see comment (3)).
(a)
Select ten plug and jack sample pairs of each type for testing (e.g. 6position/6-conductor or 8-position/8-conductor connector).
12
(b)
Insert plug into jack until latching tab locks.
13
(c)
Remove plug from jack by depressing latching tab.
14
(d)
Insert plug into jack until latching tab locks and measure mating force.
15
16
(e)
Remove plug from jack by depressing latching tab and measure unmating
force.
17
(f)
Repeat step (b) and step (c) for 49 more cycles.
18
(g)
Repeat steps (d) and step (e).
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
(4)
Durability test.
(a)
Select at least 15 sample connector pairs with a minimum of 60 contacts for
each material combination.
NOTE: A combination is defined as a plug of one material and a jack of the same or
different material.
(b)
Perform 250 mating/unmating cycles with a minimum interval between cycles
of 5 s.
NOTE: Mating and unmating of the plug and jack should be at a rate of 0.4 inch/s (10
mm/s) (see comment (4)).
(c)
Perform chemical tests to determine contact plating breakthrough (see
comment (5)).
(d)
see comment (6) for determining pass/fail conditions.
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(5)
Contact resistance, refer to Figure 13.2-2.
2
3
4
(a)
Select two sets of connectors with at least 80 total contacts in each set (i.e., a
total of 160 contacts). All contacts in a particular plug-jack combination should
be tested.
5
6
7
(b)
Precondition both sets of samples by performing five mating and unmating
cycles. These preconditioning cycles are to be performed at 20 oC +2 o, with
no cleaning of the contacts permitted.
8
9
(c)
Measure the bulk resistance of the fixed connector between points A and B,
by calculation or by measurement, for all contact pairs.
10
11
(d)
Determine the bulk resistance of the free connector between points B and C,
by calculation or by measurement, for all contact pairs.
12
13
(e)
Measure the total mated connector resistance between points A and C,
following the requirements and procedures of IEC 512-2, Test 2a (Ref A14).
14
15
16
(f)
Calculate the contact resistance by subtracting the sum of the bulk
resistances of the fixed and free connectors from the total mated connector
resistance for all contact pairs.
17
18
19
20
21
22
23
24
25
Contact resistance = RAC - (RAB + RBC)
The initial contact resistance should not exceed 20 milliOhms.
NOTE: Where practical, all intermediate connections between contacts and resistance
measurement leads should be eliminated.
26
27
28
(6)
(g)
Use the first set of 80 contacts for the temperature and humidity cycling test of
step (6).
(h)
Use the second set of 80 contacts for the mixed flowing gas environmental
test of step (7).
Temperature and Humidity Cycling Test
29
(a)
Perform a temperature and humidity cycle of:
30
1
30 minutes at 90o F (32.3 oC) and 90% relative humidity;
31
2
Two hour transition to -40o F (-40o C) and any reasonable humidity;
32
3
30 minutes at -40o F (-40o C) and any reasonable humidity;
33
4
Two and one-half hour transition to 150o F (65.6o C) and 15%
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relative humidity;
2
5
30 minutes at 150o F (65.6o C) and 15% relative humidity;
3
6
Two-hour transition back to 90o F (32.2o C) and 90% relative humidity.
4
5
(b)
Repeat step (6)(a) 49 times (i.e. all contacts are to be subjected to a total of
50 temperature and humidity cycles).
6
7
(c)
Allow 30 minutes for the samples to stabilize at room ambient temperature
and humidity conditions.
8
9
10
11
NOTE: The connectors should not be moved or contact points disturbed during
this
time.
(d) Measure contact resistance as described in step (5)(c) through step (5)(f) for
each contact in each connector.
12
13
(e)
Calculate the change in contact resistance as the difference between the
values obtained in step (6)(d) and step (5)(f) for each contact pair.
14
15
(f)
Select the four greatest contact resistance changes determined in step (6)(e)
and verify that the average of these four values are less than 15 milliOhms.
16
(7)
Environmental (Mixed Flowing Gas) Test
17
18
(a)
Perform mixed flowing gas environmental test as described in Appendix F for
Class II (see Appendix F, Table E6-1) with all 80-contact pairs mated.
19
(b)
Allow two hours for the samples to stabilize at room ambient conditions.
20
21
(c)
Measure contact resistance as described in step (5)(c) through step (5)(f) for
each contact in each connector.
22
23
(d)
Calculate the change in contact resistance as the difference between the
values obtained in step (7)(c) and step (5)(f) for each contact pair.
24
25
(e)
Select the four greatest contact resistance changes determined in step (7)(d)
and verify that the average of these four values are less than 10 milliOhms.
26
27
28
13.2.6 Alternative Methods
29
30
31
13.2.7 Suggested Test Data
None suggested.
(1)
Mating and unmating forces after the first conditioning cycle.
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(2)
Mating and unmating forces after all 50 conditioning cycles.
2
(3)
Initial and final contact resistances from steps (5)(f), (6)(d) and (7)(c).
3
4
(4)
Change in resistances for all 80 contacts from step (6)(e) and the average from step
(6)(f).
5
6
(5)
Change in resistance for all 80 contacts from step (7)(d) and the average from step
(7)(e).
7
8
9
13.2.8 Comments
(1)
Other approved chemical test methods are:
10
(a)
Nitric Acid Vapor Test per EIA-364-53 (Ref A8).
11
(b)
Gel Bulk Electrographic Test per ASTM B583-83 (Ref A3).
12
(2)
Sample selection:
13
14
15
16
17
(a)
For evaluation purposes, samples of both plugs and jacks for both gold and
non-gold contact interface systems are required. The samples of non-gold
contact interface systems should include, in addition to the proposed new
non-gold interface system, samples of all non-gold systems previously shown
to be equivalent to the defined gold interface.
18
19
20
21
22
(b)
The gold contact interface samples should meet the requirement for a gold
contact interface as defined in paragraph 15.1.1. Test samples are to have
gold plating thicknesses as close as practical to the 50-inch minimum
thickness. No connector contacts with more than 60-inch thick gold should
be used in these tests.
23
24
25
26
27
28
(c)
Non-gold contact interface system samples should meet the design
requirements of that particular system, as documented, and should be
selected so that the physical parameters of the test sample parts are on the
side of the tolerance that would produce the least favorable test results. (An
example would be the selection of parts with minimum plating thickness to
produce minimum expected durability results.)
29
30
31
32
33
34
(d)
A non-gold interface sample should be defined by a specification that is
adequate to verifying the compliance of the samples. This specification
should have sufficient detail that a competent independent laboratory/facility
can verify that the non-gold contact system complies with the specification.
An inadequate interface description, one that is too general or omits
necessary information, is reason for rejecting the proposed non-gold interface.
35
(e)
All sample plugs and jacks should meet the mechanical and dimensional
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2
requirements for six and eight position miniature plugs and jacks as described
in Subpart F of Part 68.
3
4
5
(f)
The Mating and Unmating Forces test should be performed in accordance
with EIA-364-13A (Ref A7). The maximum mating force should be 1.8 kg and
the maximum unmating force should be 0.75 kg.
6
(g)
Perform in accordance with EIA-364-09A (Ref A6).
7
8
9
10
(h)
For nickel barrier plate contact systems, a modified SO2 test method is
described in Appendix E. Other test methods are referenced in Comment 1.
For other types of barrier plating systems, tests methods applicable for that
type of material should be used.
11
12
13
(i)
The contacts should be observed using 10x magnification. No more than 10%
of the contacts tested should be broken through in the wear track. This area
is indicated by products produced by the chemical reaction.
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2
3
Figure 13.2-1 Nongold Contact Interface, Test Flow Chart
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2
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5
6
7
8
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10
11
Figure 13.2-2. Contact Resistance Connections
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14 SHDSL, HDSL2, HDSL4 TERMINAL EQUIPMENT
14.1 Metallic Signals T1.TRQ.6, 4.1.1
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5
6
7
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14.1.1 Background
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15
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14.1.2 Purpose
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30
14.1.3 Equipment
31
32
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34
35
14.1.4 Equipment States Subject to Test
SHDSL, 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, HDSL2, or HDSL4
terminal equipment. Likewise, SHDSL, 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.
Transmitting continuously at all line data rates at maximum transmit power.
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36
37
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39
40
41
42
43
44
45
14.1.5 Procedure
Measure the PSD & total power from 1 kHz to 2 MHz:
(1)
Connect the EUT (TU-R) to the companion unit (TU-C) as shown in
Figure 14.1-1.
(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 mask that represents SHDSLM(f) 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.
Note: For HDSL2 and HDSL4 see comment 4 and 5 for PSD mask.
(5)
Measure and record the PSD and total power between 1 kHz and 2 MHz. No
filter is required.
Note: For HDSL2 the band power markers would be set to 1 kHz and 350 kHz for the
total power measurement.
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 PSD from 500 kHz to 10 MHz:
(6)
Insert a high-pass filter (set to 350 kHz) into the setup as per Figure 14-2,
minding the termination. An external termination (e.g., 50  BNC) is needed for
the balun with most active filters, since they have high input impedance.
(7)
Set the vector analyzer frequency range to 500 kHz (start) and 10 MHz (stop).
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
pass band signal, and with a lower range setting.
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
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22
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39
40
41
42
43
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45
46
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 that represents SHDSLM(f) 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.
(8)
Measure and record the PSD between 500 kHz and 10 MHz.
Note: If the line rate is greater than 2 Mbps, this process is modified slightly. Adjust the
start frequency on the vector analyzer to 700 kHz instead of 500 kHz. Also, use 590
kHz on the high-pass filter instead of 350 kHz, and adjust the mask, respectively. This
adjustment may be necessary because of “bleed-over” from the passband, which is
more likely at the higher rates. 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 must not be within the window of measurement.
Measure sliding 1 MHz window (WS) power criteria in the 1.1 MHz-10 MHz band:
(9)
Without changing the setup from step (7), use the band power markers to
measure the total power in the window from 1.1 MHz to 10 MHz. 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.
Note: For HDSL2 the sliding 1 MHz window (WS) starts at 3.1 MHz.
Measure the PSD from 10 MHz to 30 MHz:
(10)
Use balun SEL#66 and filter settings as appropriate (see note (4) of Figure 14-1).
(11)
Set the vector analyzer frequency range and band power markers at 10 MHz
(start) and 30 MHz (stop). Resolution bandwidth = 100 kHz, Averaging time  10
seconds, Reference level: -50 dBm/Hz, dB/div: 10 dB and Autorange.
If applicable, load the PSD mask that represents SHDSLM(f) 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.
Note: It may be necessary to break this band up further, depending on the instruments
selected.
(12)
Measure and record the PSD between 10 MHz and 30 MHz.
Measure sliding 1 MHz window (WS) power criteria in the 10 MHz-30 MHz band:
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2
3
4
5
6
7
(13)
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 . 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.
8
9
10
11
12
13
14
15
16
17
14.1.6 Alternative Method
18
19
20
21
22
23
24
25
26
14.1.7 Suggested Test Data
27
28
29
30
31
32
33
34
35
36
37
38
14.1.8 Comments
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.
(3)
Line Data Rate and Baud Rate if applicable.
(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
T1.417-2001, the PSD mask (SHDSLM(f)) can be calculated from the following:
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
  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 ,

1
2
3
4
MaskedOffsetdB(f) is defined as:
f f

1  0.4  3dB
MaskedOffsetdB( f )  
f 3dB

1

5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23


MaskedOffsetdB( f )

1
10


10
,
f

f
int
12

f 


f 3db 


f int  f  1.1MHz

,
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 13
of T1.417-2001. 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 5.3.4.1 and
6.2.4 of T1.417-2001, the PSD mask can be determined from Table 6 and Figure
5 of T1.417-2001. 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 5.4.3.1 and 6.3.3 of
T1.417-2001, the PSD mask can be determined from Table 16 and Figure 12 of
T1.417-2001. The HDSL2 PSD and total average power is measured with a
termination of 135 Ohms.
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2
3
4
TU-R
(EUT)
5
6
7
8
9
10
11
12
Companion
(TU-C)
Figure 14.1-1 Test Configuration to Establish Data Mode
TU-R
(EUT)
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
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).
(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, 590 kHz for measurements in the 700 kHz < f < 10
MHz band, for data rates above 2Mbps.
(3)
No high-pass filter is used for 1 kHz < f < 500 kHz because this is in the
passband.
(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.
Figure 14.1-2 Test Configuration to Measure PSD and Total Power
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2
3
4
5
14.2 Longitudinal Output Voltage Limits T1.TRQ.6, 4.1.2
6
7
8
9
10
11
12
13
14.2.1 Background
14
15
16
17
14.2.2 Purpose
18
19
20
21
22
23
14.2.3 Equipment
24
25
26
27
14.2.4 Equipment States Subject to Test
28
29
30
31
32
33
34
35
36
37
38
39
40
14.2.5 Procedure
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.
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.
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12
13
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22
23
24
25
For HDSL2 refer to Table 6 of T1.417-2001 to determine the frequency range of
the “Operating Band”.
For HDSL4 refer to Table 16 of T1.417-2001 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. A correction factor of –1.3 dB must
be applied 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. A correction factor of –1.3 dB must
be applied 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.
26
27
28
29
30
31
32
14.2.6 Alternative Method
33
34
35
36
37
38
14.2.7 Suggested Test Data
39
40
41
42
43
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 then an impedance adapter must be
used. A correction factor for the adapter may be necessary.
(1)
Plot of the LOV with the limit line shown.
(2)
Line Data Rate and Baud Rate if applicable.
(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.
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3
4
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6
(2)
Care must be taken in the construction of the LOV test fixture. Resistor values
must be matched previously. Test leads from the fixture to the EUT should be
kept as short as possible to minimize RF ingress.
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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
shall 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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14.3 Transverse Balance Requirements T1.TRQ.6, 4.2
3
4
5
6
14.3.1 Background
7
8
9
14.3.2 Purpose
See Section 10.1.1
To determine transverse balance of SHDSL, HDSL2 and HDSL4 EUTs.
10
11
12
14.3.3 Equipment
(3)
Spectrum analyzer SEL# 34
13
(4)
Tracking generator SEL# 39.
14
NOTE: Refer to Section 5.3 for equipment details.
15
16
17
18
14.3.4 Equipment States Subject to Test
19
20
21
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 section 10.2.5.
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31
14.3.6 Comments
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18
(1)
For the purposes of this requirement, the applicable operating range is defined
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, metallic source impedance, and metallic voltage to
be used for transverse balance measurements of SHDSL, HDSL2 and HDSL4
terminal equipment are defined in Table 1 of T1.TRQ.6 for each of the supported
PSD masks.
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15 HEARING AID COMPATIBILITY
15.1 Hearing-Aid Compatibility – Magnetic Field Intensity 68.316
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15.1.2 Purpose
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15.1.3 Equipment
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15.1.4 Equipment States Subject To Test
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.
To measure the magnetic field characteristics of hearing aid compatible handsets to ensure
adequate magnetic coupling.
(1)
Bandpass filter SEL# 5.
(2)
Sinewave frequency generator SEL# 27.
(3)
Hearing aid probe assembly SEL# 29.
(4)
True rms ac voltmeter SEL# 40.
(5)
Reference or zero-loss codec for T1 interface SEL# XX.
(6)
Reference codec for digital telephone SEL# XX.
(7)
Zero loss analog telephone-to-IP terminal adaptor for IP network SEL# XX.
(8)
4 port 10/100 base-T ethernet hub SEL# XX.
(9)
Circuit "A" feeding circuit SEL# XX.
(10)
Circuit "B" loop simulator circuit SEL# XX.
(11)
Circuit "C" DC blocking circuit SEL# XX.
NOTE: Refer to Section 5.3 for equipment details.
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Normal off-hook talking condition.
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15.1.5.2
Axial Field Intensity and Frequency Response (Reference Figure 1,
EIA-504-1983 (Ref A10) as contained in Section 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.
(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 IPbased telephones, an appropriate test circuit and test level is to be used that produces
the same acoustic level (nominal +0 dBPa).
(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), the duration of the test
signals must be longer than the packet delay (generally ranging from 100 ms to 300 ms)
for the true rms ac voltmeter or the dynamic signal analyzer to capture the maximum
axial field intensity readings at each of the measurement frequencies.
(4)
Determine the appropriate graph from the measured axial field intensity (Figure 4A or
4B, EIA-504-1983 (Ref A10) as contained in Section 68.316).
(12)
Measure the frequency response and compare the computed value to the appropriate
graph.
(13)
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.
(14)
For receivers with axial field that exceeds -19 dB relative to 1 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 FCC Part 68.316, Figure 4A.
Radial Field Intensity and Frequency Response (Reference Figure 1,
EIA-504-1983 (Ref A10) as contained in Section 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.
(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
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and test level is to be used that produces the same acoustic level (nominal +0 dBPa).
(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. W hen testing the IP-based telephones (e.g. VoIP telephones), the duration of
the test signals must be longer than the packet delay (generally ranging from 100 ms to
300 ms) for the true rms ac voltmeter or the dynamic signal analyzer to capture the
maximum radial field intensity readings at the four measurement points in 90-degree
intervals.
(4)
Determine the appropriate graph from the measured radial field intensity as directed in
paragraph 4.3 of EIA-504-1983 (Ref A10) as contained in Section 68.316.
(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 A/m, for an input of -10 dBV at 1000 Hz. Reference
FCC Part 68.316, Section 5.3.
(6)
For receivers with axial field that exceeds -22 dB relative to 1 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 FCC Part 68.316, Figure 4B.
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15.1.7.1
None suggested.
All measurements are relative to 1 Ampere/meter.
Axial field intensity and frequency response
(1)
Input in dBV.
(2)
Output in dBV.
(3)
Normalizing factor relative to 1000 Hz.
(4)
Calculated field intensity in dB relative to 1 Ampere/meter.
(5)
Frequency.
(6)
Output in dBV for each frequency.
(7)
Net change in dBV relative to 1000 Hz for each frequency.
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Radial field intensity and frequency response
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(1)
Input in dBV.
(2)
Output in dBV.
(3)
Measurement angle.
(4)
Normalizing factor relative to 1000 Hz.
(5)
Calculated field intensity in dB relative to 1 Ampere/meter.
(1)
A chart recorder may be used to plot the data.
(2)
The probe coil output may be amplified, if needed.
(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 section are
met at any one of the available volume settings.
(4)
For Helmholz coil, built in accordance with IEEE standard 1027 (Ref A16), is required to
calibrate the hearing aid probe. The calibration procedure, in Section 5 of IEEE Standard
1027 (Ref A16), is recommended. The integrators in section 4.2 and Section 6.5.3 of
IEEE Standard 1027 (Ref A16) are not used when making the frequency response
measurements. The requirements in Figure 4A and Figure 4B of IEEE Standard 1027
(Ref A16) 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 must pass 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
Analog Telephone
Under test
1250 ohm
2W
Telephone Handset
Receiver
Note 1
48 V
Probe Coil
Optional
Bandpass Filter
Level
Recorder
True RMS
Voltmeter
Notes:
1.
The measurement axis is to be parallelled to the reference axis but may be displaced from that axis by a
maximum of 10 mm.
2.
The battery feed circuit replaces the 2.7 km loop of 26 AW G cable.
Figure 15.1-1 Setup for testing FCC Part 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
Notes:
1.
The measurement axis is to be parallelled to the reference axis but may be displaced from that axis by a
maximum of 10 mm.
2.
The ISDN telephone reference codec replaces the 2.7 km loop of 26 AW G cable.
Figure 15.1-2 Setup for testing FCC Part 68.316 HAC for ISDN 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
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
Notes:
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The measurement axis is to be parallelled to the reference axis but may be displaced from that axis by a
maximum of 10 mm.
2.
The test signal generator level is to be set to produce +0 dBPa at the telephone handset receiver.
Figure 15.1-3 Setup for testing FCC Part 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
Telephone Handset
Receiver
Note 1
Ethernet Hub
Probe Coil
(Note 2)
Level
Recorder
Optional
Bandpass Filter
True RMS
Voltmeter
Notes:
1.
The measurement axis is to be parallelled to the reference axis but may be displaced from that axis by a
maximum of 10 mm.
2.
The test signal generator level is to be set to produce +0 dBPa at the telephone handset receiver.
Figure 15.1-4 Setup for testing FCC Part 68.316 HAC for IP-based Telephone
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15.2 Hearing Aid Compatibility, Volume Control 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. Hearing aid compatible telephones must
offer both electro-magnetic coil compatibility and volume control.
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15.2.3 Equipment
To measure 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-1987
for analog telephones or ANSI/TIA-579-1991 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.
(15)
Optional 100 Hz Bandpass filter SEL# 5.
(16)
Zero loss codec for T1 interface SEL# XX.
(17)
Zero loss codec for digital telephone SEL# XX.
(18)
Zero loss analog telephone-to-IP terminal adaptor for IP network SEL# XX.
(19)
4 port 10/100 base-T ethernet hub SEL# XX.
(20)
Circuit "A" Feeding circuit SEL# 49.
(21)
Circuit "B" loop simulator circuit SEL XX.
(22)
Circuit "C" DC blcoking circuit SEL# XX.
(23)
Test loops or commercially available artifical loop equivalent to 2.7 km and 4.6 km #26
AW G non-loaded cable SEL# 50.
(24)
Artificial ear SEL# 51.
(25)
Standard microphone SEL# 52.
(26)
Microphone measuring amplifier SEL# 53.
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(27)
100 Hz to 5000 Hz sinewave frequency generator SEL# 54.
(28)
AC voltmeter with an input impedance greater than 100 kohm for bridging
measurements or equal to 900 ohm for terminated measurements SEL# 55.
NOTE: Refer to Section 5.3 for equipment details.
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15.2.5 Test procedure
Normal off-hook talking condition.
(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.
(2)
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-1987 for analog telephones and ANSI/TIA-579-1991 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.
(3)
The ROLR of the telephone under test is to be measured according to IEEE 269-1992
standard using the test circuit of Figure 5b for analog telephone or Figure 12b for ISDN,
proprietary & special use and IP-based telephone. 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 269-1992 standard should be followed.
(4)
The battery feeding bridge circuit for analog telephone is to be as shown in Figure 1 of
IEEE 269-1992 standard.
(5)
The reference codec, the zero level encoder/decoder and the analog telephone / IP
terminal adaptor 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.
(6)
The artificial ear is to be the IEC coupler for supr-aural earphones as described in ANSI
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S3.7-1973, 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)
A laboratory standard pressure microphone according to ANSI S1.12-1967[3] is to be
used for measuring the sound pressure generated in the artifical ear. The sensitivity of
the microphone should be constant over the frequency range of 100 Hz to 5000 Hz.
(8)
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.
(9)
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 IP-based
telephones since the receive level of ISDN, proprietary & special use and IP-based
telephones are independent of loop length.
(10)
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. W hen 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 must be synchronized correctly with the tracking
optional bandpass filter and its duration must be long enough for the measuring amplifier
and the level recorder to capture the maximum readings at each of the measuring
frequencies.
(11)
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.
(12)
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 661-1979 standard. The ROLR is to fall between the upper
and lower limits as defined in paragraph 4.1.2 of ANSI/TIA-470-A-1987 for analog
telephones or defined in paragraph 4.3.2.2 of ANSI/TIA-579-1991 for ISDN, proprietary
& special use and IP-based telephones.
(13)
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. The 12 dB of minimum gain must be 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.
(14)
The ROLR value determined for the
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should be subtracted from that determined for the nominal volume control setting to
determine compliance with the gain.
(15)
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). The 12 dB of gain must be achieved without significant clipping of the test
signal.
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15.2.8 Comments
None suggested.
(1)
State whether the telephone with receive volume control complies with each of the
conditions specified in the FCC Part 68.317 rule.
(2)
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-A-1987 for analog
telephones or ANIS/TIA-579-1991 for ISDN, proprietary & special use and IP-based
telephones when the receive volume control is set to its normal unamplified level.
(3)
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)
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.
(1)
This requirement applies to telephones with receive volume control.
(2)
ROLR is a loudness rating value expressed in dB of loss, more positive values of ROLR
represent lower receive levels.
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Feeding Circuit
890 ohm
1 uF
> 2H
400 ohm
Sinewave
Generator
-10 dBV
10 ohm
Analog Telephone
Under test
1250 ohm
2W
Telephone Handset
Receiver
Note 1
48 V
Probe Coil
Optional
Bandpass Filter
Level
Recorder
True RMS
Voltmeter
Figure 15.2-1 Setup for testing FCC Part 68.317 HAC volume control 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
Figure 15.2-2 Setup for testing FCC Part 68.317 HAC volume control for ISDN
Telephone
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Circuit “A”
Feeding Circuit
Circuit “C”
DC Blocking Circuit
Circuit “B”
Loop Simulator
2 uF
2 uF
2 uF
> 2H
400 ohm
> 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
Figure 15.2-3 Setup for testing FCC Part 68.317 HAC volume control 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
Figure 15.2-4 Setup for testing FCC Part 68.317 HAC volume control for IP-based
Telephone
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16 MISCELLANEOUS
16.1 Limitations on Automatic Redialing 68.318(b)
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16.1.1 Background
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16.1.2 Purpose
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16.1.3 Equipment State Subject to Test
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16.1.4 Equipment
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16.1.5 Procedure
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 must 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)
(1)
(2)
(3)
Applicable loop simulator SEL# 4.
Storage oscilloscope SEL# 23.
Network Tone Generator SEL# 68.
Consult the EUT manual to determine if the equipment has an automatic redial
feature. If it does, perform the following sequence of tests.
Configure the equipment for automatic redial testing.
(a) Connect the EUT to the circuit shown in Figure 16.1-1.
(b) Condition the EUT so that it can automatically redial a predetermined
number.
(c) Set the storage oscilloscope so that it triggers when the EUT goes off-hook
and records up to 70 s of activity.
Conduct testing for the no answer condition.
(a) Activate the automatic redial feature of the EUT.
(b) Use the network tone generator to apply audible ringing to the EUT when
dialing is complete.
(c) Using the storage oscilloscope, measure and record the time interval from
the end of dialing until the EUT goes back on hook.
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(d)
(4)
(5)
(6)
(7)
(8)
Remove the audible ringing signal after the EUT goes back on hook and
wait for it to make another redial attempt.
(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.
(f) Count and record the number of successive redial attempts.
(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.
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.
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.
For equipment that must detect compatible terminal equipment at the called party
end (e.g., modems and fax machines), conduct testing for the condition where
non-compatible terminal equipment answers.
(a) Activate the automatic redial feature of the EUT.
(b) Use the network tone generator to apply audible ringing to the EUT when
dialing is complete.
(c) After two complete audible ringing cycles, replace the network tone
-compatible
equipment answering the call.
(d) Determine that the EUT goes back on hook.
(e)
other redial
attempt.
(f) Each time the EUT makes a subsequent redial attempt, repeat steps (6)(b)
through (6)(e).
(g) 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.
(a) Activate the automatic redial feature of the EUT.
(b) For loop-start equipment, apply dial tone to the EUT approximately 200 ms
after it goes off hook.
(c) For ground-start equipment, apply CO ground to the tip conductor
approximately 200 ms after the EUT goes of hook.
(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.
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16.1.6 Alternative Methods
 None suggested.
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16.1.7 Suggested Test Data
(1)
Number of successive dialing attempts to the same number when audible ringing is
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received with no answer.
(2) Number of successive dialing attempts to the same number when busy tone is
received.
(3) Number of successive dialing attempts to the same number when reorder tone is
received.
(4) Number of successive dialing attempts to the same number when the call is
answered by non-compatible equipment.
(5) Time interval in seconds from the end of dialing until EUT goes back on hook when
audible ringing is received with no answer.
(6) Time Interval in seconds from application of busy tone until EUT goes back on hook.
(7) Time interval in seconds from application of reorder tone until EUT goes back on
hook.
(8) For loop-start EUTs with automatic dial tone detection, time interval in milliseconds
from application of dial tone to start of dialing.
(9) For ground-start EUTs, time interval in milliseconds from the application of CO
ground on the tip conductor to the start of dialing.
(10) For EUTs without automatic dial tone detection, time interval in milliseconds from
when the EUT goes off hook to start of dialing.
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16.1.8 Comments
(3)
(4)
(5)
(6)
(7)
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.
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.
Use of pulse dialing mode (if EUT is so equipped) may facilitate measurement of the
start and end of dialing.
“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.
“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).
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Loop
Simulator
Figure 16.1-1
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16.2 Line Seizure by Automatic Telephone Dialing Systems - Part 68, 68.318(c)
16.2.1 Background
The automatic telephone dialing systems referred to by this section 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.
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16.2.2 Purpose
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16.2.3 Equipment
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16.2.5 Procedure
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16.2.6 Alternative Methods
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16.2.7 Suggested Test Data
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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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(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 Part 68, Section 68.318(b).
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16.3 Telephone Facsimile Machines – Part 68, Section 68.318(d)
16.3.1 Background
In 1992 the FCC issued rules requiring that facsimile (FAX) machines identify the sender
of all messages, implementing provisions in the Telephone Consumer Protection Act of
1991. The intent was to control telemarketing nuisances such as unsolicited commercial
advertisements, automatic message dialers, and junk FAX mail. These rules first
appeared as Section 68.318(c)(3) of the FCC rules, but were later moved to Section
68.318(d). The facsimile message sender is required to identify themselves on all
messages sent. This can be done either by including identifying information in the FAX
header or footer (a.k.a. “FAX branding”), or by providing the same information on the first
page of the FAX message.
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In April 1997, responding to requests from MCI, Sprint, and Ameritech (see Order in FCC
97-117), the FCC clarified situations where the originator and the transmitter of a FAX may
be different entities or individuals, specifically with regard to FAX broadcast services. The
FCC defined “sender” as the creator of the FAX message’s content, not the service who
sends it. Consequently, each FAX must identify the business, entity, or individual who
created the FAX rather than the entity who transmits the message. In cases where the
message originator and sender agree to both be identified on the FAX, it must be clear
which is responsible for the message content and which is merely the message
transmitter.
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Manufacturers of FAX equipment have an obligation which is separate from the sender's
obligations. While a manufacturer will not be held liable if users fail to input identifying
information, it must ensure that its FAX equipment have the capability of marking
identifying information. Specifically, the FAX equipment must provide the branding
feature to users for their use. FAX equipment must provide the user with the means to
include the necessary identifying information in a header or footer of each page of a FAX
message, and must also include a statement in their customer instructions that describes
this requirement and tells the user how to set up the FAX header or footer. A sample of
this statement is shown in TIA TSB-129-A, clause 8.2.13.
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Historically (before privatization of the Part 68 equipment approval process), the FCC
required manufacturers to "attest" on the now defunct Form 730 (item 21) that their FAX
machines had the capability of marking each transmitted page with the required
information. The FCC also required manufacturers to provide consumers with instructions
on how to use the FAX machine's branding function. These instructions became part of
the test report.
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16.3.2 Purpose
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16.3.3 Equipment
Manufacturers of facsimile equipment must account for the FAX branding feature and
user instructions as per 47CFR Section 68.318(d).
None required.
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16.3.8 Comments
None.
By inspection, ensure that the manufacturer has attested that their equipment has the
FAX branding capability and have provided the user with FAX branding instructions.
This attestation and the user instructions should become part of the final test report.
A simple letter from the manufacturer attesting that their facsimile equipment has the
FAX branding capability, with a copy of the user instructions about how to implement
that feature, is sufficient to demonstrate compliance with this requirement.
None suggested
While the requirement in Section 68.318(d) puts the identification burden squarely on
the sender or originator of a facsimile message, FAX equipment manufacturers are
required to provide a means to insert the FAX header or footer (e.g., the FAX “brand”)
on every page of a FAX message. Users must also be advised about the requirement
and provided with clear and simple instructions telling how to enter information into the
FAX header or footer. Manufacturers are further advised to put the set-up instructions
in an easily accessible location and to make this process easy, making it easy for their
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customers to comply with this requirement. See also TSB-129-A, clause 8.4.13, for
more information about the user instructions.
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16.4.3 Equipment
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16.4.4 Equipment States Subject to Test
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16.4.5 Procedure
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16.4.6 Alternative Methods
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16.4.7 Suggested Test Data
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.
(6)
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.
(7)
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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16.4.8 Comments
(1)
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 Section 68.308(h) (1) (ii) 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 Section 68.308(h)(1)(ii) may be necessary in order
to determine compliance to these requirements.
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Figure A1-1. Subrate, Pulse Template, 2.4 kb/s
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Figure A1-2. Subrate, Pulse Template, 3.2 kb/s
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Figure A1-3. Subrate, Pulse Template, 4.8 kb/s
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Figure A1-4. Subrate, Pulse Template, 6.4 kb/s
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Figure A1-5. Subrate, Pulse Template, 9.6 kb/s
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Figure A1-6. Subrate, Pulse Template, 12.8 kb/s
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Figure A1-7. Subrate, Pulse Template, 19.2 kb/s
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Figure A1-8. Subrate, Pulse Template, 25.6 kb/s
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Figure A1-9. Subrate, Pulse Template, 38.4 kb/s
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Figure A1-10. Subrate, Pulse Template, 51.2 kb/s
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8.0
12.0
Time (us)
Figure A1-11. Subrate, Pulse Template, 56.0 kb/s
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8.7
Time (us)
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Figure A1-12. Subrate, Pulse Template, 72.0 kb/s
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Time (µs)
Figure A1-13. PSDS Type II Pulse Template, 144 kb/s
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Time (µs)
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Figure A1-14. PSDS Type Iii Pulse Template, 160 kb/s
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A.2 Pulse Templates for ISDN PRA and 1.544 Mbps equipment
Figures A2-1 and A2-2 show examples of possible templates as derived from the
limits given in ANSI/TIA-968-A Section 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-968-A
Section 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 d3 S  d 2 S 2  d1S  d 0
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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 Mbps, Pulse Template, Option B
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Figure A2-2. 1.544 Mbps, Pulse Template, Option C
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APPENDIX B, INFORMATIVE REFERENCES
The following documents contain provisions that do not constitute provisions of
this Document. These documents may or may not be referenced in this text.
They are supplied for information purposes only. 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.
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2. ANSI/TIA-464-C (2002), Telecommunications - Multiline Terminal Systems Requirements for PBX Switching Equipment.
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3. CS-03, (Issue 8, June 15, 1996, Industry Canada), Specification for Terminal
Equipment, Terminal Systems, Network Protection Devices, Connection
Arrangements and Hearing Aids Compatibility.
17
18
4. 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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20
21
5. IEC 60512-2-1 (2002-02) Connectors for electronic equipment - Tests and
measurements - Part 2-1: Electrical continuity and contact resistance tests- Test
2a: Contact resistance - Millivolt level method
22
23
24
6. IEC 60512-2-2 (2003-05) Connectors for electronic equipment - Tests and
measurements - Part 2-2: Electrical continuity and contact resistance tests- Test
2b: Contact resistance - Specified test current method
25
26
27
7. IEC 60512-2-3 (2002-02) Connectors for electronic equipment - Tests and
measurements - Part 2-3: Electrical continuity and contact resistance tests- Test
2c: Contact resistance variation.
28
29
8. TIA/TSB-129-A (2002), Telecommunications – Telephone Terminal Equipment U.S. Network Connections Regulatory Approval Guide
30
31
9. TIA/TSB-168-A (2003), Telecommunications – Telephone Terminal Equipment
– Labeling Requirements
32
10. TIA-579 (1991),
33
11. TIA-470-A (1987),
34
12. T1.401-2000,
1. ANSI/TIA-232-F (2002), Interface Between Data Terminal Equipment and Data
Circuit-Terminating Equipment Employing Serial Binary Data Interchange
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APPENDIX C, EXAMPLE CALCULATIONS OF WAVEFORM ENERGY
LEVELS (Informative)
2
x
E( j)   ( j)
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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.
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21
(2)
From the graph of the waveform, determine the voltage level for
interval.
22
23
(3)
Calculate the energy level using the equation. If t was selected so that the
intervals are of equal width, the equation becomes:
24
x
t
E( j) 
  Vn2
R n 1
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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  1122  1322  1402  1342  1222  1102  982
500
 852  722  602  492  392  302  222  152 )
E(j) = 0.26 joules
Figure C1-1. Calculation of Energy Levels
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Appendix D, Alternate Transverse Balance, Digital EUT (Informative)
D.1 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
well-balanced balun transformer as shown in Figure F-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
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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 balance of 30dB). For the quantified range for pass fail criteria (35dB
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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.
D.2 Purpose
To determine transverse balance of digital EUT, by using a ratio of currents.
D.3 Equipment
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12
13
(5)
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.
14
15
(6)
Two of the same model precision wound toroidal current monitors (similar to
Pearson 4100) SEL# XX.
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18
(7)
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..
19
D.4 Equipment States Subject To Test
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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 shall 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 shall be connected to the test ground
plane. Equipment which does not contain any of these potential
connections to ground shall 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.
D.5 Procedure
36
37
38
(1)
Assemble the circuit shown in Figure F-1 and connect the equipment to the
circuit as shown. The frequency range for the analyzer should be at least
200Hz < f < 2MHz.
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40
(2)
Set the analyzer's 50-ohm tracking generator output to +3dB (equivalent to
0dB into 100 ohms). With switch S2 set in position B, terminate the tip
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conductor to ground while the ring conductor is open. This represents the
worst case transverse balance condition, and there is no metallic current flow.
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.
8
9
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(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.
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25
(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 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.* Recall that the
display on the analyzer must be reduced by 6dB to get the true transverse
balance for the EUT.
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34
*Test methodologies and illustrative circuits specified in TIA-968 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 F-1: Test Fixture To Measure Transverse Balance Using A Ratio Of
Currents
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Procedure
(1)
Wash samples in distilled water.
7
(2)
Rinse samples in isopropyl alcohol.
8
(3)
Allow samples to air dry (not blown).
9
10
(4)
Place 100 ml of sulfurous acid in a 10 liter desiccator and allow to stand for 30
minutes.
11
12
(5)
Suspend samples in chamber for 24 hours at ambient temperature without
touching solution.
13
(6)
After exposure, dry samples at 80 oC for 10 minutes.
14
(7)
Prepare saturated dimethylglyoxime (DMG) solution in ethanol.
15
(8)
Mix one part of above with one part concentrated ammonium hydroxide.
16
17
(9)
Apply mixture of Step (8) to samples. The solution should completely wet
samples by aerosol spraying, immersion, or swabbing.
18
(10)
Allow samples to air dry (not blown).
19
(11)
Nickel exposure is indicated by a pink colored corrosion product.
20
21
22
23
24
25
APPENDIX E, MODIFIED SO2 METHOD (Informative)
NOTE: After drying, white crystals on surface are dried DMG. Nickel will show as
a pink colored corrosion product while base metal would have shown as
a corrosion product after exposure to sulfurous acid.
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APPENDIX F, INDUSTRIAL MIXED FLOWING GAS (Informative)
F.1 General
3
4
5
6
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8
9
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12
13
14
15
16
In the evaluation of contact interfaces for gold equivalency it is necessary to
evaluate the contact interface performance when exposed to a corrosive
atmosphere. A corrosive atmosphere is best simulated by an Industrial Mixed
Flowing Gas Test. The standards writing committees have not yet agreed upon
an Industrial Mixed Flowing Gas Test. Therefore, it was necessary to include a
complete Industrial Mixed Flowing Gas Test procedure in this document.
17
18
19
20
21
This specification covers the test procedure for producing environmentally related
corrosive atmospheres to determine the reaction of plated or unplated surfaces
when exposed to different concentrations of industrial flowing gas mixtures.
22
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31
Samples which are to be evaluated may be mated or unmated connectors,
components, or experimental materials. They are placed in an environmentally
controlled chamber which is monitored by a gas analyzing system for controlled
concentrations of the industrial gas mixture. Corrosion rates are monitored by
silver and copper control coupons placed in the chamber for each test. These
control coupons are removed and analyzed using calometric reduction for factors
related to amount and type of corrosive product growth to confirm severity control
level.
32
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34
35
36
37
38
This procedure involves the use of hazardous materials, operations, and
equipment. This specification does not purport to address all of the safety
problems associated with its use. It is the responsibility of whoever uses this
specification to consult and establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use. For specific
precautions, see Section H4. on Safety and Health.
F.2 Materials
39
(1)
40
41
The procedure selected is based upon Project TP-65 draft text developed by EIA
Engineering Committee P5.1, and is representative of the type of test being
conducted by the connector industry at present. If a procedure for Industrial
Mixed Flowing Gas testing is standardized, TR-41 will consider whether this
Appendix is to be modified or replaced.
(1)
(2)
(3)
Content
Description
Safety
Control Coupons
(a)
Copper sheet, oxygen free high conductivity, UNS C10200, 0.005 inch
thick, temper 0.5 hard.
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(b)
Silver foil, pure fine grain, 0.005 inch thick.
2
(c)
Acid, sulfuric, concentrated, AR grade.
3
(d)
Jewelers Rouge.
4
(e)
1,1,1 Trichloroethane, AR grade.
5
(f)
Deionized or distilled water.
6
(g)
Hydrochloric Acid, AR grade.
7
(h)
Methanol, AR grade.
8
9
(2)
Exposure Materials
10
(a)
Nitrogen gas, pro-purified grade or better.
11
(b)
Nitrogen dioxide gas, chemically pure grade or better.
12
(c)
Hydrogen sulfide gas. chemically pure grade or better.
13
(d)
Chlorine gas, chemically pure grade or better.
14
(e)
Clean, dry and oil-free air.
15
(f)
Gas injection equipment, for example, Teflon permeation tubes.
16
17
F.3 Test Equipment
18
(1)
19
20
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24
(a)
Coulometric Analyzer.
Coulometry for IMFG monitoring is limited to determination of sulfide and oxide
films on copper, and sulfide and chloride films on silver. Experience has shown
that monitoring these films is usually sufficient to validate the IMFG
environmental conditions of the chamber.
(b) Weight gain equipment.
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29
Coupon Evaluation Equipment
(c)
Other.
NOTE: provided correlation with coulometric method has been demonstrated.
(2)
Environmental Chamber
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(a)
The environmental chamber is to consist of an enclosure made of
noncorrosive, nonmetallic materials contained within a cabinet, oven,
or incubator capable of maintaining the temperature within the
specified ranges, see Table E6-1. A commercially available
environmental chamber will suffice.
6
7
8
(b)
The constant temperature chamber for permeation tubes, if used, is to
be capable of controlling the temperature within +1 oC over a
temperature range of 15-30 oC.
9
(3)
Source of clean dry air
10
11
12
(4)
Appropriate gas analysis equipment for calibrating and monitoring the gas
concentrations in the chamber. The gas analysis equipment is to be capable
of the following accuracy:
13
14
15
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18
19
20
Total Sulfur Analyzer
+1 ppb at 20% upper
range limit
NO2 Analyzer
+4 ppb at 80% upper range limit
+1 ppb at 20% upper
Cl2 Analyzer
+4 ppb at 80% upper range limit
+4%
range limit
21
22
(5)
Temperature and humidity monitoring equipment, capable of an accuracy of
+0.5 oC and +1% relative humidity, respectively.
23
F.4 Safety and Health Considerations
24
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32
Do not perform these procedures unless the operator is fully trained in handling
hazardous materials and knowledgeable of the appropriate precautions
necessary to perform this test. Appropriate safety and health representatives
should be consulted for any other prerequisites or proper procedures prior to
performing this specification. The safety and environmental procedures to
observe include, but are not limited to, the following items:
(1)
Material Safety Data Sheets with first aid information have been obtained for
all chemicals used both in cleaning and testing.
33
34
(2)
The operator has received the Safety Sheets and become familiar with normal
precautions for handling corrosive and toxic materials.
35
36
37
(3)
All necessary safety equipment is available including a properly functioning,
well lighted fume hood, eyewash station/shower, large sink with running
water, acid resistant glove and apron, chemical goggles and acid spill kit.
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(4)
All chemicals have been properly labeled and will be properly stored in
accordance with OSHA and EPA Regulations.
3
(5)
Arrangements for proper storage and disposal of chemicals have been made.
4
F.5 Sample Preparation
5
(1)
6
7
8
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12
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14
15
Control Coupon Preparation
This is a critical process in conducting the test and therefore the same method
should be used each time the test is performed. Improper cleaning may
introduce contaminants which can affect the corrosion rates and mechanisms.
The following method has been found to produce reproducible results.
WARNING! PERFORM ALL WORK WITH ACIDS, SOLVENTS, OR GASES IN
A FUME HOOD. CHEMICAL GOGGLES, OR FACE SHIELD, SHALL BE
WORN. OBSERVE PRECAUTIONS IN HANDLING CORROSIVE AGENTS.
(a)
Copper
16
1. Vapor degrease with 1,1,1 trichloroethane or equivalent for 1 minute.
17
2. Rinse thoroughly with methanol.
18
3. Rinse thoroughly with deionized or distilled water.
19
4. Etch with 15% solution of sulfuric acid at 50 oC for 2 minutes.
20
5. Rinse with deionized or distilled water.
21
6. Dry with clean, dry, filtered air.
22
23
(b)
Silver
24
1. Dip in concentrated hydrochloric acid for 2 minutes.
25
2. Rinse with deionized or distilled water.
26
3. Dry with clean, dry, filtered air.
27
4. Buff with jewelers rouge.
28
29
5. Ultrasonically clean with 1,1,1 trichloroethane or equivalent
for 1 minute.
30
6. Repeat cleaning with fresh 1,1,1 trichloroethane.
31
7. Air dry (not blown).
32
8. Vapor degrease with 1,1,1 trichloroethane or equivalent for 1 minute.
33
9. Air dry (not blown).
34
35
10. Clean cathodically in a boiling solution of trisodium phosphate using
an inert anode for 1 minute at a current of 1.0 ampere.
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11. Rinse thoroughly with distilled or deionized water.
2
12. Dry with clean, dry, filtered air.
3
4
5
6
NOTES:
(1) Control coupons should be handled with clean forceps at all times with the
exception the of buffing in Step (4) above.
7
8
(2)
9
(3)
Store coupons in a sealed container which has been filled with an inert gas
(i.e., nitrogen), or an evacuated desiccator until used.
Test Sample Preparation
10
11
12
13
Samples are to be tested in the "as received condition" unless otherwise
specified. All surfaces that are not intended for exposure and could influence the
various measurements are to be protected.
F.6 Procedure
14
(1)
Calibration
15
16
17
18
WARNING! PERFORM ALL WORK WITH ACIDS, SOLVENTS, OR
GASES IN A FUME HOOD. CHEMICAL GOGGLES, OR FACE SHIELD,
SHALL BE WORN. OBSERVE PRECAUTIONS IN HANDLING
CORROSIVE AGENTS.
19
20
21
22
23
Prior to the start of a test, all gas concentration monitoring equipment is to be
calibrated by the operator to known standards following procedures outlined
by the equipment manufacturers. After start of the test, the monitoring
equipment is to be calibrated at least every 5 days and on the final day of
testing in order to ensure that the readings are accurate.
24
25
26
27
28
NOTE: Some chlorine monitors cannot differentiate between chlorine and
some other pollutant gases. Those monitors will only require calibration prior
to the beginning of testing and just after the final day of testing as these are
the only times that the other gases can be eliminated from the chamber to
allow a determination of the chlorine levels.
29
(2)
Pretest Procedures
30
31
32
(a)
Adjust humidity and temperature according to environmental severity
class specified as indicated in Table E6-1, without samples in
chamber.
33
34
35
(b)
Allow chamber to stabilize for temperature and humidity without
samples. Exchange rate is to be adjusted to provide 6 changes per
hour.
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(c)
Currently, chlorine concentration is to be adjusted and stabilized first;
this gas cannot be monitored in combination with the other pollutants.
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4
5
6
(d)
Figure E6-1 defines the zone configuration of a typical test chamber.
Control coupons are to be placed in the shaded zones of Figure E6-2.
Inert, noncorrosive materials are to be used for suspending the test
samples and control coupons in the test chamber.
7
8
9
10
11
(e)
Place samples and control coupons in chamber as soon as possible
after stabilization period. They are to be placed such that there is a
minimum space of 2 inches between samples, coupons and the
chamber walls. Random placement of the samples at the various
measurement intervals throughout the test is important.
12
13
(f)
Sample orientation is to be chosen to minimize obstruction of the air
flow.
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15
16
(g)
Because of absorption of gases by the samples, allow chlorine
concentrations to stabilize and adjust, if necessary, to the desired
concentration.
17
18
19
(h)
The remaining pollutants (NO2 and H2S) are then to be introduced into
the test chamber and adjusted for the concentrations of the requested
exposure class in Table E6-1.
20
21
22
(i)
Total reactive corrosion area of samples and control coupons
compared to the volume in inner chamber is to be such that the
concentrations of the gasses can be maintained throughout the test.
23
(3)
Test Procedures
24
25
26
WARNING! PERFORM ALL WORK WITH ACIDS, SOLVENTS, OR GASES IN
A FUME HOOD. CHEMICAL GOGGLES, OR FACE SHIELD, SHALL BE
WORN. OBSERVE PRECAUTIONS IN HANDLING CORROSIVE AGENTS.
27
28
(a)
A recommended exposure time for the test samples is 20 days unless
otherwise specified in the referencing document.
29
30
31
32
33
34
(b)
In many cases it may be advantageous to withdraw samples for
periodic testing prior to the full time of the test. After removal from the
chamber, such samples are to be stabilized at ambient room
temperature for a minimum of 2 hours, measured for appropriate
response, and returned to the chamber if required. Such withdrawals
are to be noted in the test report.
35
36
37
(c)
The interior of the environmental chamber is to be monitored daily for
humidity, temperature, and pollutant concentration. If adjustment is
required, additional monitoring is to be performed. Concentration of
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(d)
chlorine gas is to be adjusted only at the start of the test and checked
at the completion of the test, since chlorine concentration cannot be
analyzed in combination with the other pollutants. However, the initial
chlorine flow rate is to be maintained throughout the test.
5
6
7
8
(e)
At the conclusion of the test, the test samples is to be removed from
the chamber and stabilized at ambient room temperature for a
minimum of 2 hours before making the final readings
or
measurements.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
(4)
Control Coupon Exposures
WARNING! PERFORM ALL WORK WITH ACIDS, SOLVENTS, OR GASES IN
A FUME HOOD. CHEMICAL GOGGLES, OR FACE SHIELD, SHALL BE
WORN. OBSERVE PRECAUTIONS IN HANDLING CORROSIVE AGENTS.
(a)
A minimum of 3 coupons each of copper and silver, for each time
interval and location in the test chamber, is to be placed in the
chamber to monitor corrosion film growth rates. A minimum of 3
coupons of each type are to be removed after an exposure time of 48
hours, and a minimum of another 3 coupons of each type after 95
hours. A new set of coupons are to then be placed in the chamber to
monitor the next major time interval, and again a minimum of 3
coupons of each type are to be removed after the 48 and 95 hour
exposure time.
(b)
Recommended major time intervals during a typical 20-day test are
as follows:
25
1. between the 1st and 4th day of the test;
26
2. between the 9th and 12th day; and,
27
3. from the 16th through the 20th day.
28
29
30
31
(c)
Control coupons are used to monitor the reaction rate in the chamber
and not the deterioration of the test samples. Coupons removed from
the chamber are not to be returned to the chamber.
32
33
34
35
(d)
Whenever possible, in order to minimize instability of the test
conditions within the chamber, any test samples required to be
removed on a certain day is to be removed at the same time as the
control coupons are being removed or replaced.
36
(5)
Control Coupon Evaluation
37
38
Control coupons removed from the chamber are to be analyzed using any
method in Section H3 to verify chamber conditions.
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F.7 Documentation
2
3
Data Sheets are to contain:
(a) title of test;
4
(b)
sample description;
5
(c)
test equipment;
6
(d)
number of samples;
7
(e)
test procedure;
8
(f)
actual pollutant concentrations used in the test (H2S, NO2, Cl2);
9
10
(g)
deviations from test conditions during sample exposure (charts to be
supplied if necessary);
11
(h)
date of test and name of operator.
12
F.8 Summary
13
14
The following details are to be specified in the referencing document:
(a) number of samples to be tested;
15
(b)
duration of exposure, if other than specfied in Section E(3), Step (a);
16
(c)
test severity class;
17
(d)
sample preparation and descriptions of product to be tested;
18
(e)
sample measurement intervals.
19
F.9 Historical
20
21
22
The development of test environmental conditions and relationship to field
environment studies was done by William Abbot, Battelle Columbus Laboratory.
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2
3
Figure F6-1. Chamber Zone Configuration
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2
Figure F6-2. Control Coupon Locations
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