Download TR41.3-07-05-003b-NIPP-NAI-2007

TR41.3-07-05-003b
NIPP – Network, Interfaces, Power and Protection
NIPP-NAI – Network Access Interfaces
Nashville, TN February 12 - 16, 2007
NIPP-NAI-2007-036R1
CONTRIBUTION
TITLE:
SOURCE*:
PROJECT:
Remote End POTS Splitter Requirements
Editor1
Splitters
_______________________________
ABSTRACT
This contribution outlines the requirements for static splitter testing regarding ADSL and
VDSL splitters. Splitters are used for protection of typical POTS devices when ADSL or
VDSL services are deployed on the same copper pair.
This revision is a result of the input gathered at the Nashville, TN meeting, February 12 –
14, 2007 along with specific changes outlined by contributions NIPP-NAI-2006-150R1,
NIPP-NAI-2007-003, NIPP-NAI-2007-005, NIPP-NAI-2007-032, and NIPP-NAI-2007033.
This contribution contains updates to NIPP-NAI-2006-079R2 agreed to by this
subcommittee. The exact changes are reflected in living list NIPP-NAI-2007-028R1.
R1 of this document contains un update to section 4.7.3. In the original version the
section was incorrectly titled DSL to Line insertion Loss. The correct VDSL Non-Linear
Distortion titled has been added.
It is the intent of the subcommittee to utilize this contribution for letter ballot as quickly
as possible.
_______________________________
1
CONTACTS:
Christian Duran; Corning Cable Systems; [email protected]; Tel: 817-337-7230; Fax: 817-431-7554
Erin Blake; Corning Cable Systems; [email protected]; Tel: 817-431-7306; Fax: 817-431-7554
Page 1 of 24
TABLE OF CONTENTS
1
SCOPE AND PURPOSE ......................................................................................... 5
1.1
1.2
1.3
SCOPE ........................................................................................................................... 5
PURPOSE ...................................................................................................................... 5
OTHER CONSIDERATIONS ......................................................................................... 5
2
REFERENCED STANDARDS ................................................................................ 6
3
DEFINITIONS, ABBREVIATIONS, ACRONYMS AND SYMBOLS ......................... 7
3.1
3.2
4.
REMOTE END SPLITTER REQUIREMENTS ......................................................... 9
4.1
4.1.1
4.2
4.2.1
4.2.2
4.3
4.4
4.5
4.5.1
4.5.2
4.6
4.6.1
4.6.2
4.6.3
4.7
4.7.1
4.7.2
4.7.3
5.
DEFINITIONS................................................................................................................. 7
ABBREVIATIONS, ACRONYMS AND SYMBOLS ........................................................ 7
INTRODUCTION ............................................................................................................ 9
Remote End Splitter Function Location ................................................................................... 9
TEST REQUIREMENTS .............................................................................................. 11
Frequencies Used in Testing-Test Requirements ..................................................................11
Balanced Terminations ..........................................................................................................12
ZHP-R AND ZNL-R IMPEDANCES DEFINED ............................................................ 12
MAINTENANCE TEST SIGNATURES (MTS) ............................................................. 12
SIGNALING REQUIREMENTS.................................................................................... 13
Applied Ringing Signals .........................................................................................................13
DC Resistance .......................................................................................................................14
VOICE BAND REQUIREMENTS ................................................................................. 15
Metallic Balanced (Differential Mode) .....................................................................................15
POTS to Line Longitudinal Balance .......................................................................................18
Transparent Testing Capacitance ..........................................................................................19
VDSL BAND TESTING ................................................................................................ 20
DSL Band Attenuation ............................................................................................................21
DSL to Line Insertion Loss .....................................................................................................22
DSL to Line Insertion Loss .....................................................................................................22
INFORMATIVE REFERENCES............................................................................. 24
Page 2 of 24
TABLE OF FIGURES
Figure 4-1: Structure of remote end DSL splitter ............................................................................ 9
Figure 4-2: NID deployed remote end splitter .............................................................................. 10
Figure 4-3: Ancillary remote end splitter ....................................................................................... 10
Figure 4-4: Remote end splitter located inside the home ............................................................. 11
Figure 4-5: Remote end splitter located inside the modem .......................................................... 11
Figure 4-6: ZHP-r of DSL port termination for voice band testing ................................................ 12
Figure 4-7: ZNL-r of POTS port termination for voice band testing .............................................. 12
Figure 4-8: Maintenance test signature ......................................................................................... 13
Figure 4-9: Transmission measurements in the voice band ........................................................ 17
Figure 4-10: POTS to line return loss measurement .................................................................... 18
Figure 4-11: POTS to line longitudinal balance measurement per IEEE 455 .............................. 19
Figure 4-12: Capacitance measurement ...................................................................................... 20
Figure 4-13: DSL band attenuation measurement ....................................................................... 22
Figure 4-14: VDSL to line insertion loss measurement ................................................................ 22
Page 3 of 24
TABLE OF TABLES
Table 4-1: POTS to line insertion loss requirements ..................................................................... 15
Table 4-2: Attenuation distortion requirements ............................................................................. 16
Table 4-3: POTS to line group delay requirements ....................................................................... 17
Table 4-4: POTS to line return loss requirements ......................................................................... 17
Table 4-5: POTS to line intermodulation distortion requirements ................................................. 18
Table 4-6: POTS to line longitudinal balance requirements .......................................................... 19
Table 4-7: Profile frequency minimum and maximum ................................................................... 20
Table 4-8: DSL band attenuation requirements ............................................................................ 21
Table 4-9: VDSL to line insertion loss requirements ..................................................................... 22
Table 4-10: Remote End VDSL2 splitter intermodulation test parameters ................................... 22
Page 4 of 24
Remote End POTS Splitter Requirements
1 SCOPE AND PURPOSE
1.1
SCOPE
This technical requirement document defines a minimal set of static electrical requirements for a
remote end splitter. The parameters defined include terminations, frequencies, testing, test
signatures, dc characteristics, voice-band characteristics, attenuation, envelope delay distortion,
impedance, longitudinal balance, and metallic balance. Additional features and performance
characteristics such as dynamic testing are beyond the scope of this document.
Dynamic testing of a splitter is performed in a live POTS and xDSL modem environment. This
includes, but is not limited to, a complete system setup using CO and remote splitters, xTU-C and
xTU-R modems, CO ringers and a telephone. Performance of the splitter is measured by
evaluating the Layer 1 primitives reported by the xTU-C and xTU-R (CRCs, FECs, etc.) during
on-hook, off-hook, ringing, and ring trip events. This work is being covered by the DSL Forum.
The reader should note that implementations addressing the applications described herein may
also be subject to other industry specifications such as TIA-968-A, GR-1089-CORE, and UL
documents.
1.2
PURPOSE
This technical requirement document is intended to facilitate the provisioning of various digital
subscriber line (DSL) technologies and voice band services over the same loop. The document is
written broadly to permit the remote end splitter to be used for current DSL technologies and
potential new DSL technologies that use the same frequency spectra.
1.3
OTHER CONSIDERATIONS
Network systems apply various electrical signals to the subscriber loop for the purpose of network
maintenance and alerting the customer of an incoming call. These signals vary considerably in
amplitude and can reach values of -/+ 200Vdc for maintenance functions and 276.2 volts peak for
alerting signals. When these signals are applied to an access line that also has a remote end
splitter wired in series with the subscriber loop, the low pass section of the splitter may see the
full magnitude of these signals. Therefore consideration should be given to the selection of circuit
components used for the splitter design. During the times these signals are applied, it is
acceptable that the low pass filter does not perform all of its functions nor meet all of the technical
requirements in this document. However the filter components should not be permanently
damaged.
Such phenomena as lightning and over voltage due to inductive interference or power cross lie
beyond the scope of this Technical Requirements document.
The detailed technical parameters of the network maintenance, alerting signals, and safety
referenced here can be found in the informative references in Section 5.
Page 5 of 24
2 REFERENCED STANDARDS
The following standards contain provisions that, through reference in this text, constitute
provisions of this technical requirements document. At the time of publication, the editions
indicated were valid. All standards 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 standards indicated below.
[1] ANSI T1.413 - Network and Customer Installation Interfaces – Asymmetrical Digital Subscriber
Line (DSL) Metallic Interface, Committee T1-Telecommunications, 1998.
[2] ANSI T1.417 - Spectrum Management for Loop Transmission Systems – 2001
[3] ATIS T1.TRQ.PP.10-2003 – Splitters used for Line Splitting and Line Sharing Applications 2003
[4] ANSI T1.424-2004 - Interface Between Networks and Customer Installations – Very-High
Speed Digital Subscriber Lines (VDSL) Metallic Interface - 2004
[5] IEEE Standard 455 - IEEE Standard Test Procedure for Measuring Longitudinal Balance of
Telephone Equipment Operating in the Voice Band, 1985 or later.
[6] IEEE Standard 743 - IEEE Standard Equipment Requirements and Measurement Techniques
for Analog Transmission Parameters for Telecommunications, 1995.
[7] Telcordia Technologies GR-57-CORE Issue: 01 2001-10-19, Functional Criteria for Digital
Loop Carrier Systems
[8] Telcordia Technologies GR-506-CORE Issue: 01 1996-00-00, - LSSGR: Signaling for Analog
Interfaces
[9] ITU-T G.993.2; Series G: Transmission Systems and Media, Digital Systems and Networks,
Digital transmission systems - Access networks, Very high speed digital subscriber line
transceivers 2 (VDSL2)
Page 6 of 24
3 DEFINITIONS, ABBREVIATIONS, ACRONYMS AND SYMBOLS
3.1
DEFINITIONS
Narrow band services Services that use a small portion of the 0Hz to 4 kHz frequency band.
Splitter
A network comprised of frequency-domain filters that separate the highfrequency DSL signals from the voice-band signals, at the respective
ports (DSL and POTS) (frequently called POTS splitters even though the
voice-band signals may comprise more than voice).
Sub-voice band
The 0Hz to 200Hz frequency band.
Voice band
The 200Hz to 4 kHz frequency band.
Voice band services Services that use the 300Hz to 4 kHz band or a major portion of it.
3.2
ABBREVIATIONS, ACRONYMS AND SYMBOLS
ADSL
ADSL+
ATM
BB
caps
CO
CPE
DAML
DC
DCR
DSL
DSLAM
ERL
FDI
HB
HDSL
HPF
LB
LPF
mA
MDF
NB
NID
nF
POTS
PSTN
RL
rms
RT
SAI
SDP
SDSL
SFRL
SHDSL
asymmetric digital subscriber line
asymmetric digital subscriber line with higher available bit rates
asynchronous transfer mode
broad-band
capacitors
central office
customer premise equipment
digital added main line
direct current
direct current resistance
digital subscriber line
digital subscriber line access multiplexer
echo return loss
feeder distribution interface
high-band
high bit-rate digital subscriber line
high-pass filter
longitudinal balance
low-pass filter
milli-amp
main distribution frame
narrow-band
network interface device
nano-Farad
plain ordinary telephone service
public switched telephone network
return loss
root-mean-square
remote terminal
serving area interface
subscriber demarcation point
symmetrical digital subscriber line
single frequency return loss
symmetrical high bit-rate digital subscriber line
Page 7 of 24
SRL-Hi
SRL-Lo
TU-C
TU-R
U-C
uF
U-R
usec
VDSL
xDSL
ZNL-r
ZHP
ZHP-r
ZTC
ZTR
singing return loss high
singing return loss low
DSL transceiver unit, central office end
DSL transceiver unit, remote end
“U” interface – central office end
micro Farad
“U” interface – remote end
microsecond
very high bit-rate digital subscriber line
types of DSL such as ADSL, ADSL+, HDSL, SDSL, SHDSL, or VDSL
non-loaded cable compromise impedance as seen from the remote
high-pass filter impedance
high-pass filter impedance of TU-R
network terminating impedance
remote telephone terminating impedance
Page 8 of 24
4.
REMOTE END SPLITTER REQUIREMENTS
4.1
INTRODUCTION
A service splitter is required at both ends of the line that carries DSL signals if existing narrowband services are to remain unaffected by the presence of DSL signals on the same wire-pair.
The requirements for a service splitter at the remote customer side are defined in this clause.
The term ‘splitter’ could be interpreted to include both a high-pass filter for the DSL, and a lowpass filter for voice. It should be noted, though, that most implementations of a remote-end
‘splitter’ do not include the high-pass filter functionality.
Such functionality is typically
implemented in the DSL transceiver. 2
The structure of the remote end splitter is given in Figure 4-1. The DSL port connects to the DSL
transceiver. The POTS port shall connect to the existing voice band equipment. The POTS-toLINE port function is that of a low-pass filter. Certain isolation is required between POTS and
DSL ports to prevent undesirable interaction between DSL and the used narrow-band service.
The remote end DSL splitter requirements guarantees the proper operation of POTS on lines that
carry DSL signals.
POTS
PORT
LPF
LINE
PORT
DSL
PORT
Figure 4-1: Structure of remote end DSL splitter
The remote end DSL splitter shall meet the requirements with all DSL transceiver impedance
values that are tolerated by its return loss specification.
4.1.1
Remote End Splitter Function Location
The remote end splitter can be located in four different locations, the NID, next to the NID, inside
the home, or inside the TU-R.
4.1.1.1 Splitter Located in the NID
Figure 4-2 shows the splitter when it is incorporated in a NID.
2
This document does not prohibit the inclusion of the high-pass filter functionality in the splitter.
Page 9 of 24
PSTN
NID
CO Splitter
POTS & DSL
POTS
LPF
Primary
Protector
TU-R
LOOP
LPF
MODEM
Remote End
Spliter
POTS
DATA
Figure 4-2: NID deployed remote end splitter
4.1.1.2 Splitter Located Next to the NID
Figure 4-3 shows the splitter when it is located in an ancillary position to the NID.
PSTN
NID
CO Splitter
POTS & DSL
POTS
LPF
Primary
Protector
TU-R
LOOP
MODEM
LPF
Remote End
Splitter
DATA
POTS
Figure 4-3: Ancillary remote end splitter
4.1.1.3 Splitter Located Inside the Home
Figure 4-4 shows the splitter when it is located inside the home. Splitters inside the home are
usually installed in a central location. Depending on the particular subscriber home wiring a
subscriber may be adept enough to install a splitter in the home.
Page 10 of 24
PSTN
NID
TU-R
CO Splitter
POTS & DSL
POTS
LPF
Primary
Protector
LPF
Home Remote
End Splitter
LOOP
POTS
MODEM
DATA
Figure 4-4: Remote end splitter located inside the home
4.1.1.4 Splitter Located With the TU-R Modem
Figure 4-5 shows the splitter when it is implemented with the TU-R modem. This configuration is
very similar to the splitter located inside the home. The TU-R with integrated splitter will be
installed in a central location so as to route the necessary internal CPE wiring.
PSTN
NID
CO Splitter
TU-R
POTS & DSL
POTS
LPF
Primary
Protector
LOOP
LPF
Integrated
Remote end
Splitter
POTS
MODEM
DATA
Figure 4-5: Remote end splitter located inside the modem
4.2
TEST REQUIREMENTS
4.2.1
Frequencies Used in Testing-Test Requirements
Two bands of frequencies shall be used for testing; voice band and DSL band. Testing shall not
be performed between 4 – 25 kHz but it is expected that the LPF shall be well behaved in this
area (i.e., the amplitude response is monotonically decreasing from 4 to 24 kHz)
Page 11 of 24
4.2.2
Balanced Terminations
All testing shall be done in a BALANCED (i.e. metallic) method. Test equipment with unbalanced
connections may be used as long as the resultant measurement maintains balance. Balun
transformers are often used on test equipment with unbalanced connections.
4.3
ZHP-R AND ZNL-R IMPEDANCES DEFINED
To facilitate testing of the DSL splitter independently of the actual modem or specific vendor,
ZHP-r is defined to allow proper termination of the DSL port during voice band testing for the
splitter at the remote customer end. (See Figure 4-6) The ZHP-r is valid only for voice band
frequencies.
ZNL-r is defined as lumped impedance models of loops for remote-end splitter design. The
requirements for ZNL-r are shown in Figure 4-7.
0.10 µF
0.12 µF
100 Ohm
0.10 µF
0.47 mH
0.12 µF
Component Tolerances Capacitors = 2.5%, Resistors = 1%, Coils = 5%
Figure 4-6: ZHP-r of DSL port termination for voice band testing
348 Ohm
1300 Ohm
100 nF
Component Tolerances Capacitors = 2.5%, Resistors = 1%
Figure 4-7: ZNL-r of POTS port termination for voice band testing
4.4
MAINTENANCE TEST SIGNATURES (MTS)
If the maintenance test signatures are provided for the remote-end splitter, they shall be as
shown in Figure 4-8.
In order to allow the DSL splitter to be managed by the network operational support systems and
to be identified by metallic loop test systems, the remote end DSL splitter function may contain a
signature that is activated by the metallic test systems. The signature is unique for all North
Page 12 of 24
American remote end VDSL/ADSL splitters. The signature is designed to be active only during
the maintenance mode and will not interfere with normal operation of the circuit. The signature is
located on the POTS side of the LPF function protecting the DSL band frequencies from the nonlinear effects of the diodes.
Tip
0.47 µF, 10%
6.8V, 10%
33 kOhm , 1%
Ring
Figure 4-8: Maintenance test signature
4.5
SIGNALING REQUIREMENTS
Unless otherwise noted, all of the requirements in this standard shall be met in the presence of all
of the following:



POTS loop currents from 0 mA to 100 mA;
POTS tip-to-ring DC voltages of 0 VDC to -60 VDC;
POTS ringing signals that meet the criteria in 4.5.1.
Compliance with the loop current range above may be demonstrated by meeting the
requirements of this standard with loop currents of 0, 20, 40, 60, 80 and 100 mA (+/- 1 mA for all
values) with a -50 VDC +/- 1 VDC source.
Compliance with the DC voltage range above may be demonstrated by meeting the requirements
of this standard with DC voltages of 0, -20, -40, and -60 VDC (+/- 1 VDC for all values) with 40
mA +/- 1 mA of loop current.
4.5.1
Applied Ringing Signals
For the purposes of meeting the ringing signal requirement in clause 4.5, applied ringing signals
shall meet the following criteria:





The DC component of the ringing signal shall be between 0 VDC and -60 VDC.
The AC component of the ringing signal shall be 20 Hz +/- 1 Hz;
The AC component of the ringing signal shall have an open circuit voltage of 104 Vrms
+/- 1 Vrms;
The AC component of the ringing signal shall have a crest factor of 1.4142 +/- .01
The AC component of the ringing signal shall be applied for 2.0 seconds +/- 0.2 seconds
and removed for 4 seconds +/- 0.4 seconds, then reapplied and removed for the same
durations in a repeating pattern that lasts at least two minutes.
Compliance with the applied ringing signal specified above may be demonstrated by meeting the
requirements of this standard with the ringing signal characteristics specified above with a DC
component of 0, -20, -40, and -60 VDC (+/- 1 VDC for all values).
Page 13 of 24
There is no specification for AC current during ringing because the rms value is typically less than
the DC current limit of 100 mA based on 104 VAC open circuit voltage and a five REN (1,400
ohm) load.
During a ring trip event there is a possibility that a large amount of current can flow through the
loop for a short period of time. Since the input of the majority of DSL low pass filters is inductive,
there is a high probability that this high current will saturate the magnetic material of these
inductive components. When saturation occurs, the inductive components will fail to operate
correctly. This can result in loss of data for a short period of time and can lower the quality of
service for video applications. Ring trip current can reach values of up to 1.0 Arms
4.5.2
DC Resistance
The DC resistance from tip to ring at the POTS interface with the U-R interface shorted shall be
less than or equal to 25 ohms. This requirement shall be met before and after all ring-trip events.
The DC resistance from tip to ground and from ring to ground at the POTS interface with the U-R
interface open shall be greater than or equal to 5 Mohms.
Page 14 of 24
4.6
VOICE BAND REQUIREMENTS
4.6.1
Metallic Balanced (Differential Mode)
4.6.1.1 Test Loops
Loops to be used for ADSL testing are divided into two groups. This is done to obtain more
specific requirements under a widely varying conditions of short and long loops and to account for
the effect the opposite splitter impedances being seen through the loop and effecting
performance.
Short Loops:
0, 0.5 Kft, 2.0 Kft, 5 Kft pairs of 26 AWG cables.
Long Loops:
ANSI T1.601 resistance design loops 7, 9, 13 and T1 TR28 CSA loops 4, 6, 7, 8.
Loops to be used for testing of VDSL splitters are defined in Section 12.1 of T1.424-2004
4.6.1.2 POTS to Line Insertion Loss
For each of the test loops specified in 4.6.1.1, the insertion loss from the source to the termination
shall be measured with and without the splitter/ZHP combination inserted. The increase in
insertion loss in the pass band on any of the test loops is due to the splitter/ZHP combination.
The requirements are defined in Table 4-1. Figure 4-9 defines the test configuration that shall be
used for all pass band insertion loss measurements for the remote end splitter.
Table 4-1: POTS to line insertion loss requirements
Splitter
Loop
ZTC (Ω)
ZTR (Ω)
Insertion loss (dB)
Frequency (kHz)
POTS
Short ADSL
Loops
900
600
< 1.0
1.004
POTS
Long ADSL
Loops
900
600
< 0.75
1.004
POTS
All VDSL
Loops
900
600
< 1.0
1.004
4.6.1.3 Attenuation Distortion in the Voice Band
The defined ZHP shall be connected to the DSL port of the splitter (if the splitter is an internal part
of the TU-R, then the modem remains connected as the DSL load). The attenuation distortion is
the increase of loss over frequency relative to the insertion loss at 1004 Hz caused by the
splitter/ZHP combination (or modem) measured in Figure 4-9. The requirements for attenuation
distortion are defined in Table 4-2.
Page 15 of 24
Table 4-2: Attenuation distortion requirements
Splitter type
Loop
ZTC Ω
ZTR Ω
Insertion loss (dB)
Frequency (kHz)
POTS
Short ADSL
Loops
900
600
± 1.5
0.2 to 3.4
POTS
Short ADSL
Loops
900
600
± 2.0
3.4 to 4.0
POTS
Long ADSL
Loops
900
600
+0.5, -1.5
0.2 to 3.4
POTS
Long ADSL
Loops
900
600
+0.5, -1.5
3.4 to 4.0
POTS
All VDSL
Loops
900
600
± 1.5
0.2 to 3.4
POTS
All VDSL
Loops
900
600
± 2.0
3.4 to 4.0
NOTE: Attenuation is a positive value, gain is a negative value.
POTS
U-R
U-C
Remote End POTS Splitter
POTS
Test Equipment
ZTR
LINE
Test Loop
LPF
DSL
ZHP-r
(Load)
NOTES

ZTC = 900 Ohm

ZTR = 600 Ohm

ZHP-r is the impedance presented to the POTS connection by a TU-R
Page 16 of 24
ZTC
Figure 4-9: Transmission measurements in the voice band
4.6.1.4 POTS to Line Envelope Delay Distortion
The envelope delay distortion of the remote end splitter shall be measured using the test
configuration of Figure 4-9. The increase in delay distortion caused by the remote end splitter as
measured from the POTS port to the U-R interface, for each of the test loops specified in 4.6.1.1,
shall meet the requirements of Table 4-3.
Table 4-3: POTS to line group delay requirements
Splitter Type
Loop
ZTC
(Ω)
ZTR
(Ω)
EDD (µs)
Frequency (kHz)
POTS
All Loops
900
600
200
0.2 to 3.2
POTS
All Loops
900
600
250
3.2 to 4.0
4.6.1.5 POTS to Line Return Loss
The remote-end VDSL splitter shall meet the return loss requirements defined in Table 4-4 with
and without ZHP connected. Individual frequencies start at 2200 Hz and sweep to 3400 Hz.
Return loss measurements shall be made in accordance with IEEE 743. Figure 4-10 defines the
test configuration that shall be used for return loss measurements on the remote end splitter.
Table 4-4: POTS to line return loss requirements
Splitter type
Loop
ZTR
(Ω)
ERL
SRL-L
SRL-H
(dB)
(dB)
(dB)
Comments
POTS
All Loops
600
>6
>5
>3
POTS
All Loops
600
N/A
N/A
>2
Page 17 of 24
Single frequency
POTS
U-R
U-C
Remote End POTS Splitter
POTS
Test Equipment
LINE
ZTC
Test Loop
LPF
DSL
ZHP-r
(Load)
ZNL-r
Return loss reference
impedance
NOTES

ZNL-r is the impedance of the non-loaded loop model seen from the RT

ZHP-r is the impedance presented to the POTS connection by a TU-R
Figure 4-10: POTS to line return loss measurement
4.6.1.6 POTS to Line Intermodulation Distortion
The intermodulation distortion contributed by the remote end splitter shall be measured using the
test configuration of Figure 4-9 and the null loop. With an applied tone set per IEEE 743, at a
level of -9 dBm, the second and third order intermodulation distortion products shall meet the
requirements of Table 4-5.
Table 4-5: POTS to line intermodulation distortion requirements
Splitter Type
Loop
ZTC
(Ω)
ZTR
(Ω)
2nd Order
(dB)
3rd Order
(dB)
Frequency
(kHz)
POTS
Null Loop
900
600
< -57
< -60
0.2 to 4.0
4.6.2
POTS to Line Longitudinal Balance
The longitudinal balance of the POTS splitter can be measured using two different techniques.
One technique is to treat the DSL splitter as a separate entity, which would require using a twoport test. The other technique is to treat the splitter, TU-C, and CO line card combination as a
one-port network. One port tests are usually performed on network end splitters.
4.6.2.1 POTS to Line Longitudinal Balance – Two-Port Technique
Two-port test method shall be used when testing the DSL splitter as a separate entity.
The longitudinal balance of the DSL splitter (without loops), measured as a two-port device in
either direction between the POTS and line port, shall be measured in accordance with IEEE
Standard 455 [12]. The DSL port shall be shorted in the case where DC blocking capacitors are
included as part of the splitter function. Otherwise, the DSL port shall be open. Because of the
Page 18 of 24
maintenance signature, the applied longitudinal voltage shall be a maximum of 3.0 V peak to
peak. A DC bias current of 25 mA shall be applied. The POTS to line longitudinal balance
requirements are specified in Table 4-6.
Table 4-6: POTS to line longitudinal balance requirements
Splitter Type
Loop
ZTC
(Ω)
ZTR
(Ω)
Long. Balance Two-Port
(dB)
Frequency
(kHz)
POTS
No Loop
900
600
> 58
0.2 to 1.0
POTS
No Loop
900
600
> 58 – 53 linearly
decreasing
3.2 to 4.0
The termination of the test set is for a series balance measurement per IEEE Standard 455 [12].
Prior to testing, a test circuit balance of 77 dB (58 + 19 dB) shall be achieved to insure 1 dB of
accuracy.
Figure 4-11 shows the test setup for the remote end DSL splitter with the DSL port open. If
testing longitudinal balance on an integrated network modem, the TU-R shall be connected but
powered down.
DSL Port
DSL
LB Test
Load
LINE
POTS
LB Test
Load
Figure 4-11: POTS to line longitudinal balance measurement per IEEE 455
4.6.3
Transparent Testing Capacitance
To minimize the effect of the splitter on the performance of metallic loop test systems, the input
impedance is defined for a special narrow frequency band.
4.6.3.1 Tip to Ring Capacitance
The intent of this requirement is to limit the maximum capacitance seen by metallic testing
systems. By setting this limit, the metallic test systems can test POTS services with the accuracy
and dependability of today.
Overall the admittance of the POTS or PSTN port shall be capacitive.
The capacitance present at either the POTS or PSTN interfaces in the frequency range of 20 to
30 Hz shall be a maximum of 300 nF. This amount includes the total capacitance due to the two
splitters at the network end and the remote end with the attached modems.
Page 19 of 24
The following, per end, maximum/minimums shall be met:
Remote end splitter without modem connected:
 115 nF Max
 20 nF Min
Modem input allowance:
 35 nF Max
 20 nF Min
Multiplying the above numbers by two (for two modems and two POTS splitters) results in 300 nF
maximum tip to ring capacitance.
DSL Port
DSL
LINE
POTS
 Capacitance
Figure 4-12: Capacitance measurement
4.6.3.2 Capacitance to Ground
There shall be no designed AC path to ground. The maximum stray capacitance from either tip
or ring of the splitter to ground shall be less than 1.0 nF.
4.7
VDSL BAND TESTING
The start and stop frequencies for testing in the DSL band are dependent on the technology
(ADSL vs. VDSL). For VDSL splitters, the start and stop frequencies are dependent on the
different profile options. The start frequency is denoted fmin will and the stop frequency is denoted
fmax.
Table 4-7: Profile frequency minimum and maximum
Fmin [kHz]
Fmax [MHz]
Splitter Type
ADSL
32
1.104
ADSL
VDSL, 8a
25
8.5
VDSL2
VDSL, 8b
25
8.5
VDSL2
VDSL, 8c
25
8.5
VDSL2
Page 20 of 24
4.7.1
VDSL, 8d
25
8.5
VDSL2
VDSL, 12a
25
12
VDSL1, VDSL2
VDSL, 12b
138
12
VDSL1, VDSL2
VDSL, 17a
138
17.7
VDSL2
VDSL, 30a
138
30
VDSL2
DSL Band Attenuation
The insertion loss of the low-pass filter and ZHP (i.e., the difference in insertion loss measured
with and without the filter/ZHP combination), measured as shown in Figure 4-13, shall meet the
requirements in Table 4-8. The insertion loss caused by the low pass filter in the DSL band shall
be measured with an input level of 10 dBm.
Table 4-8: DSL band attenuation requirements
Splitter type
Loop
Line
(Ω)
ZTR
(Ω)
Insertion loss
(dB)
Frequency
(kHz)
POTS
Null Loop
100
600
> 65
32 - 300
POTS
Null Loop
100
600
> 55
300 - fmax
DSL Port
ZHP-r
POTS
LPF
Line Port
S
I
G
Vm
600 Ohm
Source 100 ohm
fmin - fmax Balanced
Page 21 of 24
Figure 4-13: DSL band attenuation measurement
4.7.2
DSL to Line Insertion Loss
The Insertion loss caused by the splitter in the DSL band between nominal impedances as shown
in Figure 4-14 shall meet the limits defined in Table 4-9. The insertion loss caused by the low
pass filter in the VDSL band shall be measured with an input level of -10 dBm.
Table 4-9: VDSL to line insertion loss requirements
Splitter Type
Loop
Line (Ω)
ZTR (Ω)
Insertion loss
(dB)
Frequency
(kHz)
POTS
Null Loop
100
600
0.5
fmin to fmax
DSL Port
Vm
100 Ohm
POTS
LPF
Line Port
S
I
G
600 Ohm
Source 100 ohm
fmin - fmax Balanced
Figure 4-14: VDSL to line insertion loss measurement
4.7.3
VDSL Non-Linear Distortion
The line and DSL ports of the splitter are terminated with 100 Ω and the POTS port is terminated
in 600 Ω. Two tones with frequencies specified in Table 4-10, each with a power of 8.5 dBm, shall
be injected into the DSL port and distortion shall be measured at the line port. The measured
spurious levels shall meet the requirements that IM2 and IM3 are less than the power levels
specified in the table.
Table 4-10: Remote End VDSL2 splitter intermodulation test parameters
VDSL2 Profile
Frequency 1
(MHz)
Frequency 2
(MHz)
IM2 (dBc)
IM3 (dBc)
8
0.12
3.8
≤ TBD
≤ TBD
Page 22 of 24
8
0.12
5.1
≤ TBD
≤ TBD
8
3.8
5.1
≤ TBD
≤ TBD
12 & 17
5.1
8.8
≤ TBD
≤ TBD
30
11.8
24.0
≤ TBD
≤ TBD
Page 23 of 24
5.
INFORMATIVE REFERENCES
ANSI T1.401.01-2000, “Interface between Carriers and Customer Installations - Analog Switched
Access Lines with the Line-Side Answer Supervision Feature.”
ATIS Committee T1Technical Requirements Document “Technical Requirements- Maximum
Voltage, Current, and Power Levels in Network Powered Devices.”
U.S. Department of Agriculture, Rural Utilities Services, Bulletin 1753E-001 (Form 522), “RUS
General Specification for Digital, Stored Program Controlled Central Office Equipment, RUS Form
522.”
UL 60950; Underwriting Laboratories, “The Standard for Safety of Information Technology
Equipment including Electrical Business Equipment.”
UL 1863; Underwriting Laboratories, “Communications-Circuit Accessories”, Issue 4, May 14,
2004
UL 497A; Underwriting Laboratories, “Secondary Protectors for Communications Circuits”, Issue
3, March 20, 2001.
Telcordia Technologies GR-1089-CORE Issue: 03 2000-06-30, – Electromagnetic Compatibility
and Electrical Safety – Generic Criteria for Network Telecommunications Transmission
Requirements and Objectives of the LATA Switching Systems Generic Requirements (LSSGR).
Telcordia Technologies GR-506-CORE Issue: 01 1996-00-00, - LSSGR: Signaling for Analog
Interfaces
Page 24 of 24