ETSI TS 101 952-3 V1.1.1 (2012-02)

Technical Specification
Access, Terminals, Transmission and Multiplexing (ATTM);
Access network xDSL splitters for European deployment;
Part 3: Generic specification of static distributed filters for
xDSL over POTS
2 ETSI TS 101 952-3 V1.1.1 (2012-02)

Reference
RTS/ATTM-06019
Keywords
2-WIRE, access, ADSL, analogue, broadband,
distributed filters, POTS, splitter, VDSL
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ETSI
3 ETSI TS 101 952-3 V1.1.1 (2012-02)
Contents
Intellectual Property Rights . 6
Foreword . 6
Introduction . 7
1 Scope . 8
2 References . 8
2.1 Normative references . 8
2.2 Informative references . 9
3 Definitions, symbols and abbreviations . 10
3.1 Definitions . 10
3.2 Symbols . 11
3.3 Abbreviations . 12
4 General functional description of xDSL over POTS distributed filters . 13
4.1 Functional diagram . 14
4.2 High pass filter . 14
5 Circuit definitions, testing conditions and methods . 14
5.1 DC and ringing testing conditions . 14
5.1.1 Polarity independence . 14
5.1.2 DC feeding conditions (on-hook/off-hook) . 15
5.1.3 DC feeding and loading bridges . 15
5.1.4 Ringing signal voltage . 16
5.2 AC Terminating impedances . 16
5.2.1 Z and Z . 16
refDSL DSL
5.2.2 Z and Z , off-hook impedances . 17
R SL
5.2.3 Z , xDSL band impedance . 17
RHF
5.2.4 Z , on-hook high impedance . 17
OnHI
5.2.5 Z , on-hook low impedance . 18
OnLI
5.2.6 Z , impedance on-hook . 18
OnHo
5.2.7 Z , load impedance for ringing. 18
ring
5.2.8 Z , impedance of the metering device . 19
Meter
5.3 Absence of a high pass filter . 19
5.4 General transmission test setup . 19
5.4.1 General definition of the Insertion Loss (IL) measurement . 20
5.4.2 POTS signal loss: IL between LINE port and POTS port. 20
5.4.3 xDSL signal isolation: IL between LINE and POTS port . 21
5.4.4 xDSL signal loss: IL between LINE port and xDSL port . 22
5.4.5 General definition of the Return Loss . 23
5.4.6 Return Loss test set-up at LINE port and POTS port . 23
5.5 Unbalance measurement . 24
5.5.1 General definition of Longitudinal Conversion Loss . 24
5.5.2 General definition of Longitudinal Conversion Transfer Loss . 25
5.5.3 LCL and LCTL test set-up . 25
5.6 Noise measurement . 26
5.6.1 Psophometric noise in the POTS Band . 26
5.6.2 Noise in the xDSL Band . 26
5.7 Common Mode Rejection Ratio measurement . 26
6 Distributed filter requirements . 27
6.1 Classification of distributed filters according to requirements . 27
6.1.1 Justification of the classification . 27
6.1.2 Basic filter requirements . 27
6.1.3 Standard filter requirements . 27
6.1.4 Enhanced filter requirements . 28
6.1.5 Option A and Option B as defined for central splitters . 28
ETSI
4 ETSI TS 101 952-3 V1.1.1 (2012-02)
6.1.6 Option A and Option B as used for distributed filters . 28
6.1.7 Correlation and trade-offs between filter requirements (for information) . 28
6.2 DC requirements . 29
6.2.1 DC Insulation resistance between A-wire and B-wire . 29
6.2.2 DC series resistance . 29
6.2.3 DC signalling . 29
6.3 Ringing frequency requirements . 30
6.3.1 Ringing voltage drop at 25 Hz and 50 Hz . 30
6.3.2 Z impedance at 25 Hz and 50 Hz . 30
InRing
6.3.3 Total harmonic distortion at 25 Hz and 50 Hz . 30
6.4 POTS pass band loss requirements (on-hook) . 31
6.4.1 On-hook requirement for the case of high impedance termination . 31
6.4.2 On-hook requirement for the case of low impedance termination . 31
6.5 POTS Pass band loss requirements (off-hook) . 32
6.6 POTS Passband return loss requirements (off-hook) . 33
6.6.1 Return loss requirements at the POTS port . 33
6.6.1.1 Return Loss at the POTS port for Option A . 33
6.6.1.2 Return Loss at the POTS port for Option B . 34
6.6.2 Return Loss requirements at the LINE port Option A . 34
6.6.2.1 Return Loss at the Line Port Option A for Basic Filters . 34
6.6.2.2 Return Loss at the Line Port Option A for Standard Filters . 35
6.6.2.3 Return Loss at the Line Port Option A for Enhanced Filters . 35
6.6.3 Return Loss requirements at the LINE port Option B . 36
6.6.3.1 Return Loss at the Line Port Option B for Basic Filters . 36
6.6.3.2 Return Loss at the Line Port Option B for Standard Filters . 37
6.6.3.3 Return Loss at the Line Port Option B for Enhanced Filters . 38
6.7 Requirements relating to metering pulses at 12 kHz or 16 kHz (optional). 38
6.8 Unbalance about Earth . 39
6.9 xDSL band requirements . 39
6.9.1 xDSL band on-hook isolation between LINE and POTS port . 40
6.9.2 xDSL band off-hook isolation between LINE and POTS port . 40
6.9.2.1 xDSL band off-hook loss requirements for basic filters. 40
6.9.2.2 xDSL band off-hook loss requirements for standard filters . 40
6.9.2.3 xDSL band off-hook loss requirements for enhanced filters . 41
6.9.3 Transition band signal loss: IL between POTS port and LINE port (optional) . 41
6.9.4 xDSL signal loss: IL between LINE port and xDSL port . 41
6.10 Noise . 41
6.10.1 POTS band audible noise level requirements . 42
6.10.2 xDSL band noise level . 42
6.11 Distortion . 42
6.11.1 POTS band intermodulation distortion (optional) . 42
6.11.2 DSL band intermodulation distortion (optional) . 42
6.12 Group delay distortion . 43
6.13 Requirements related to POTS transient effects (optional) . 43
Annex A (normative): Particular requirements for passive distributed filters . 44
A.1 Z and Z for specific xDSL over POTS variants . 44
DSL RefDSL
A.1.1 Generic definition of Z , using Z , C and L . 44
DSL RefDSL DSL DSL
A.1.2 Z for ADSL over POTS . 45
DSL
A.1.3 Z for European VDSL1 over POTS, with US0 starting at 25 kHz . 45
DSL
A.1.4 Z for VDSL2 over POTS with US0 . 45
DSL
A.2 Common requirements for passive distributed filters . 46
A.3 Specific requirements for passive filters for ADSL over POTS variants . 49
A.4 Specific requirements for passive filters for VDSL1 over POTS variants . 49
A.5 Specific requirements for passive filters for VDSL2 over POTS variants . 50
Annex B (informative): Evolution of the documents . 51
Annex C (informative): Correlation and trade-offs between filter requirements . 52
ETSI
5 ETSI TS 101 952-3 V1.1.1 (2012-02)
C.1 Detrimental effect of parallel distributed filters . 53
C.2 Trade-off between properties in POTS band and xDSL band . 55
C.3 Strong IL in the xDSL band affects POTS quality . 59
C.4 Effects of parallel filters differ at POTS and LINE port . 59
C.5 The effects of absence of the xDSL impedance Z . 60
DSL
Annex D (informative): Intrinsic IL and RL caused by the Z in the POTS band . 61
DSL
Annex E (informative): IL Measurement from LINE to xDSL inside Z . 62
DSL
Annex F (informative): Return Loss measurements: practical diagrams. 63
Annex G (informative): Insertion Loss measured with feeding and loading bridges . 65
Annex H (informative): Dynamic tests of distributed filters in the presence of xDSL
transceivers . 67
H.1 General Description of TR-127 of the Broadband Forum . 67
H.2 Distributed filter tests in TR-127. . 67
Annex I (informative): Optimal transmission of POTS and xDSL signals and their
separation . 68
Annex J (informative): More on feeding and loading bridges . 69
Annex K (informative): Additional requirements for Active Filters (F.F.S.) . 70
K.1 DC series resistance. 70
K.2 Bidirectional IL tests . 70
K.3 Noise measurements methods for active filters . 70
K.3.1 Psophometric noise in the POTS Band. 70
K.3.2 Noise in the xDSL Band . 71
K.4 On-hook loss requirements for dynamic or active filters . 71
K.5 Noise requirements for active filters . 71
K.5.1 POTS band audible noise level . 71
K.5.2 xDSL band noise level . 71
K.6 Distortion . 71
K.7 Transitional tests . 71
Annex L (informative): Amending the IL measurements for finite Z . 72
OnHo
Annex M (informative): Bibliography . 75
History . 76

ETSI
6 ETSI TS 101 952-3 V1.1.1 (2012-02)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Access, Terminals, Transmission
and Multiplexing (ATTM).
The present document is part 3 of a multi-part deliverable covering Access network xDSL transmission filters, as
identified below:
Part 1: "Generic specification of xDSL over POTS splitters";
Part 2: "Generic specification of xDSL over ISDN splitters and xDSL universal splitters";
Part 3: "Generic specification of static distributed filters for xDSL over POTS";
Part 4: "Additional specifications for dynamic distributed filters for xDLS over POTS (under study)".
NOTE 1: The present document is derived from previous specifications of distributed filters for ADSL over POTS.
Before the publication of the 3 (or 4) parts as described above, the TS 101 952 was composed of 2 parts,
which discriminated between ADSL and VDSL, with several subparts. For reasons of simplicity the TS is
now restructured as a set of only 3 (potentially 4) documents, intended for both ADSL and VDSL when
applicable. The older structure of the documents is explained in the informative Annex B.
NOTE 2: Useful information on splitter tests also applicable to distributed filters may be found in
TR 101 953-1-1 [i.3] and TR 101 953-2-1 [i.5]. These documents are linked to the previous versions of
the splitter specifications. [i.3] and [i.5] e.g. describe the combination of the AC testing conditions of the
test set-ups with the DC conditions controlled via feeding and loading bridges. If there is a discrepancy
between the present document and the TR 101 953 series of documents [i.3] to [i.8], the present document
prevails.
NOTE 3: The use of distributed filters is not recommended for VDSL, but it is not excluded. For this reason the
parts 3 and 4 refer to distributed filters for xDSL and not just for ADSL.
NOTE 4: In the present document we introduce three classes of filters: basic, standard and enhanced. The reasoning
behind this approach is clarified in Clause 6.1.1.
NOTE 5: When multiple distributed filters are installed in parallel the quality of the POTS band signals tend to
degrade proportionally to the number of filters placed at the customer's premises. This effect is explained
in Clause C.1. This degradation effect is worse if multiple distributed filters of basic quality are used, or
filters that only fulfil the previous published requirement (TS 101 952-1-5 (V1.2.1) [i.17]). In that case
also the DSL signals can potentially be degraded. The latter is further addressed in the informative
Annex B.
The present document is fully in line with initiative "eEurope 2002 - An Information Society For All", under "The
contribution of European standardization to the eEurope Initiative, A rolling Action Plan" especially under the key
objective of a cheaper, faster and secure Internet.
ETSI
7 ETSI TS 101 952-3 V1.1.1 (2012-02)
Introduction
Remarks and limitations of the present document.
The present document covers all xDSL system variants, such as ADSL1, ADSL2, ADSL2plus, VDSL1 and VDSL2. It
is applicable at only at the Terminal Equipment (TE) (i.e. user) side of the line. There is no equivalent of the distributed
filter at the CO side. The CO side central splitter requirements for xDSL over POTS splitters are in TS 101 952-1 [11].
The present document is derived from previous specifications of distributed filters for ADSL over POTS, and it corrects
the errors of the older versions as explained in Annex B. It now contains measurements and requirements for the
combined effect when multiple distributed filters are deployed in parallel.
A number of limitations and remarks of the present document should be listed:
1) Originally the present document was limited to distributed filters for ADSL. It is now extended to cover also
distributed filters for VDSL. In the ITU-T documents a warning note is recommending not to use distributed
filters for VDSL. E.g. see note 7 of section 5.4 of G.993.2 [i.13]). However, if distributed filters are used in
VDSL2 scenarios to achieve a faster and cheaper deployment of service, operators should realize that this
could prevent VDSL to attain its maximum theoretical transmission performances, and that ERM/EMC
problems of the VDSL could worsen.
2) The present document covering xDSL over POTS distributed filters was gained from the experience with
passive and static DSL splitters, the original state of the art for this application. Therefore, the requirements in
the present document are primarily intended for passive and static distributed filters at the TE side only.
3) There are other classes of filters possible, besides passive and static splitters. Such active and/or dynamic
filters are composed of other elements than passive components. Active/dynamic splitters require different and
additional requirements and test methods to be specified. Indeed, the dynamic behaviour of the splitter could
allow the requirements to differ depending on the state of the line, e.g. requiring isolation, attenuation,
rejection and insertion loss values to be adapted to the on-hook and the off-hook state of the line. The full
specification of requirements for active/dynamic splitter is F.F.S. An introduction to this is in the informative
Annex K. Additional requirements might be in TS 101 952-4 [i.14] (under study).
4) Distributed filters have less stringent isolation requirements than central splitters. The non-linearity of some
telephone sets may then cause audible back-ground noise in the POTS band, disturbing the phone conversation
and potentially even reducing the DSL capacity, particularly when the phone is picked-up.
5) Besides testing static requirements according to the present document, there exists a dynamic testing
methodology, compiled by the broadband forum, in TR-127 [i.15]. The TR-127 [i.15] methodology for POTS
splitters and filters is now published. A tutorial text on TR-127 [i.15] is given in informative Annex H. The
TR-127 [i.15] test methodology is considered a useful method of assessing overall filter performance and
could be carried out complementarily to the present specification. For certain properties the TR-127 [i.15]
methodology is sometimes the only feasible method at an acceptable complexity. Indeed, TR-127 [i.15] may
prove that a filter works correctly in a worst case xDSL test environment, including POTS DC and ringing
signals. The use of the TR-127 [i.15] methodology for this purpose is suggested for certain clauses in the
present document, but out of scope.
6) The use of Option A and B for defining Return Loss is kept in the present document in exactly the same way
as it is used for POTS splitters.
ETSI
8 ETSI TS 101 952-3 V1.1.1 (2012-02)
1 Scope
The present document specifies requirements and test methods for "xDSL over POTS" distributed filters. These filters
are at the user side of the local loop in the customer premise.
• Unlike the splitters (sometimes called central splitters to distinguish them from distributed filters) described in
TS 101 952-1 [11] and TS 101 952-2 [12], the distributed filters do not contain a high pass part. Therefore,
only the low pass part is tested.
• Furthermore, the central splitters mentioned above are used as a single device at each end of the line.
Distributed filters are often not used as a single device, but as multiple parallel devices. This aspect, which was
not tested in a previous version of the present document (see note 5 of the Foreword and the informative
Annex B), is now tested also.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] ETSI TBR 038: "Public Switched Telephone Network (PSTN); Attachment requirements for a
terminal equipment incorporating an analogue handset function capable of supporting the justified
case service when connected to the analogue interface of the PSTN in Europe".
[2] ITU-T Recommendation O.42: "Equipment to measure non-linear distortion using the 4-tone
intermodulation method".
[3] ETSI ES 203 021-3: "Access and Terminals (AT); Harmonized basic attachment requirements for
Terminals for connection to analogue interfaces of the Telephone Networks; Update of the
technical contents of TBR 021, EN 301 437, TBR 015, TBR 017; Part 3: Basic Interworking with
the Public Telephone Networks".
NOTE: ETSI TBR 021 has been made historical.
[4] ITU-T Recommendation O.41: "Psophometer for use on telephone-type circuits".
[5] ITU-T Recommendation O.9: "Measuring arrangements to assess the degree of unbalance about
earth".
[6] ETSI ES 201 970: "Access and Terminals (AT); Public Switched Telephone Network (PSTN);
Harmonized specification of physical and electrical characteristics at a 2-wire analogue presented
Network Termination Point (NTP)".
[7] ETSI EN 300 659-1: "Access and Terminals (AT); Analogue access to the Public Switched
Telephone Network (PSTN); Subscriber line protocol over the local loop for display (and related)
services; Part 1: On-hook data transmission".
[8] ETSI ES 200 778-1: "Access and Terminals (AT); Analogue access to the Public Switched
Telephone Network (PSTN); Protocol over the local loop for display and related services;
Terminal equipment requirements; Part 1: On-hook data transmission".
ETSI
9 ETSI TS 101 952-3 V1.1.1 (2012-02)
[9] ETSI ES 201 729: "Public Switched Telephone Network (PSTN); 2-wire analogue voice band
switched interfaces; Timed break recall (register recall); Specific requirements for terminals".
[10] ETSI ES 201 187: "2-wire analogue voice band interfaces; Loop Disconnect (LD) dialling specific
requirements".
[11] ETSI TS 101 952-1: "Access network xDSL splitters for European deployment; Part 1: Generic
specification of xDSL over POTS splitters".
[12] ETSI TS 101 952-2: "Access, Terminals, Transmission and Multiplexing (ATTM); Access
network xDSL splitters for European deployment; Part 2: Generic specification of xDSL over
ISDN splitters and xDSL universal splitters".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 102 139: "Compatibility of POTS terminal equipment with xDSL systems".
[i.2] ETSI TR 101 728: "Access and Terminals (AT); Study for the specification of low pass filter
section of POTS/ADSL splitters".
[i.3] ETSI TR 101 953-1-1: "Access and Terminals (AT); Unified and Generic Testing Methods for
European Specific DSL splitters; Part 1: ADSL splitters for European deployment; Sub-part 1:
Specification of Testing methods for Low Pass part of ADSL/POTS splitters".
[i.4] ETSI TR 101 953-1-2: "Access network xDSL transmission filters; Part 1: ADSL splitters for
European deployment; Sub-part 2: Testing methods for High Pass part of ADSL/POTS splitters".
[i.5] ETSI TR 101 953-2-1: "Access network xDSL transmission filters; Part 2: VDSL splitters for
European deployment; Sub-part 1: Specification of Testing methods for low pass part of
VDSL/POTS splitters".
[i.6] ETSI TR 101 953-2-2: "Access network xDSL transmission filters; Part 2: VDSL splitters for
European deployment; Sub-part 2: Specification of Testing methods for high pass part of
VDSL/POTS splitters".
[i.7] ETSI TR 101 953-1-3: "Access network xDSL transmission filters; Part 1: ADSL splitters for
European deployment; Sub-part 3: Testing methods for ADSL/ISDN splitters".
[i.8] ETSI TR 101 953-2-3: "Access network xDSL transmission filters; Part 2: VDSL splitters for
European deployment; Sub-part 3: Specification of Testing methods for VDSL/ISDN splitters".
[i.9] ITU-T Recommendation G.992.1: "Asymmetric Digital Subscriber Line (ADSL) transceivers".
[i.10] ITU-T Recommendation G.992.3: "Asymmetric Digital Subscriber Line transceivers 2 (ADSL2)".
[i.11] ITU-T Recommendation G.992.5: "Asymmetric Digital Subscriber Line (ADSL) transceivers -
Extended bandwidth ADSL2 (ADSL2plus)".
[i.12] ITU-T Recommendation G.993.1: "Very high speed Digital Subscriber Line transceivers
(VDSL)".
[i.13] ITU-T Recommendation G.993.2: "Very high speed Digital Subscriber Line transceivers 2
(VDSL2)".
[i.14] ETSI TS 101 952-4: "Access, Terminals, Transmission and Multiplexing (ATTM); Access
network xDSL splitters for European deployment; Part 4: Additional specifications for dynamic
distributed filters for xDLS over POTS (under study)".
NOTE: This Document is under construction.
ETSI
10 ETSI TS 101 952-3 V1.1.1 (2012-02)
[i.15] Broadband Forum TR-127: "Dynamic Testing of Splitters and In-Line Filters with xDSL
Transceivers", Issue 1.
NOTE: This document can be downloaded at http://www.broadband-forum.org/technical/download/TR-127.pdf.
[i.16] ETSI TS 101 952-1-5 (V1.1.1): "Access network xDSL transmission filters; Part 1: ADSL splitters
for European deployment; Sub-part 5: Specification for ADSL over POTS distributed filters".
NOTE: This document is part of the earliest version of the distributed filter specifications. See comments in
Annex B.
[i.17] ETSI TS 101 952-1-5 (V.1.2.1): "Access network xDSL transmission filters; Part 1: ADSL
splitters for European deployment; Sub-part 5: Specification for ADSL over POTS distributed
filters".
NOTE: This document is part of the most recent previous version of the POTS splitter specs. See comments in
Annex B.
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
A-wire and B-wire: wires in the 2-wire local loop connection provided from the exchange to the NTP
active splitter or active distributed filter: splitter or filter containing some active components
balun: transformer, used to convert balanced into unbalanced signals or vice-versa
central splitter: splitter that is used to isolate xDSL frequencies from POTS frequencies at a single point (often called
NTP) at the customer's premises; (occasionally it is also called a master splitter)
distributed filter: low pass filter that is added in series with each of the parallel connected POTS TE
NOTE: Each of these parallel connected filters (in the in-house cabling) is known as a distributed filter. These
filters are also known as In-line filters or microfilters.
dynamic splitter or dynamic distributed filter: splitter or filter changing its transfer behaviour dynamically,
e.g. based on the state of the POTS connection
far end echo: speech that is fed back to the talker in a telephony connection with a round trip delay (i.e. the delay
between talking and hearing the feedback), of greater than 5 ms, resulting in a distinguishable echo
master splitter: See central splitter.
Network Termination Point (NTP): demarcation point between the access pair and the in-house wiring, where often
the central splitter is placed
off-hook: state of the POTS equipment at either end of a loop connection when the NTP terminal equipment is in the
steady loop state
NOTE: See ES 203 021-3 [3]. In the case where multiple TEs are present at the customer end of the loop, then the
TE is considered to be off-hook from the perspective of testing the central splitter or the distributed filter
when one terminal is off-hook.
on-hook: state of the POTS equipment at either end of a POTS loop connection when the NTP terminal equipment is in
the quiescent state
NOTE: See ES 203 021-3 [3]. In the case where multiple TEs are present at the customer end of the loop, then the
TEs is considered to be on-hook from the perspective of testing the central splitter or the distributed filter
only when all terminals are on-hook.
ETSI
11 ETSI TS 101 952-3 V1.1.1 (2012-02)
passive splitter or passive distributed filter: splitter or filter containing exclusively passive components
sidetone: speech that is fed back to the talker in a telephony connection with a round trip delay (i.e. the delay between
talking and hearing the feedback), of less than approximately 5 ms, making it indistinguishable from the original
utterance
static distributed filter: distributed filter not intended to change its transfer function based on the state of the POTS
connection
NOTE: These filters are also known as single state distributed filters.
static splitter: splitter not intended to change its transfer function based on the state of the POTS connection
NOTE: These splitters are also known as single state splitters.
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Att Attenuation in the xDSL Band (LINE port to xDSL port, or reversed)
DB
C The capacitor C part of the Z
DSL DSL
f highest of the used frequencies in the xDSL Band
H
f lowest of the used frequencies in the xDSL Band
L
f intermediate frequency, at the edge between US or US0 and the DS band for xDSL
M1
f maximum frequency above xDSL band for measurements
Max
IL Insertion Loss xDSL Band Off-Hook
DBOffH
IL Insertion Loss (Isolation) xDSL Band On-Hook
DBOnH
IL Maximal Insertion Loss Off-Hook (in the POTS band)
MaxOffH
IL Maximal Insertion Loss On-Hook (Low Impedance, in the POTS band)
MaxOnH
IL Insertion Loss for Metering (Off-Hook)
Meter
IL Insertion Loss POTS Pass Band On-Hook
PBOnH
IL Insertion Loss Transition Band, only measured in Off-Hook
TBOffH
IL Maximal Insertion Loss Variation Off-Hook (in the POTS band)
VarOffH
IL Maximal Insertion Loss Variation On-Hook (Low Impedance, in the POTS band)
VarOnH
LCL Longitudinal Conversion Loss
LCL LCL at the LINE port
LINEport
LCL LCL at the POTS port
POTSport
LCTL Longitudinal Conversion Transfer Loss
LCTL LCTL from POTS port to LINE port
POTStoLINE
L The inductance L part of the Z
DSL DSL
N Noise in the xDSL band
DB
N Noise in the POTS band (psophometric)
PB
R DC resistance between A and B wire
AtoB
R DC Resistance of a splitter or filter for POTS current
DC
R The resistive R part of the Z (R ≡ Z )
DSL DSL DSL RefDSL
R Variable DC feed resistor in Figure 3
FEED
R Variable DC load resistor in Figure 4
LOAD
RL Return Loss POTS Pass Band Off-Hook
PBOffH
S Switch to connect xDSL impedance Z to the test set-up
DSL DSL
S Switch to connect N-1 filters to the test set-up, in parallel with the main filter DUT
PAR
UaE Unbalance about Earth in the POTS Band
PB
V V Ring-Drop
RD
Z Generic name for the AC POTS impedance models
AC
Z Impedance model of the input filter of a particular xDSL
DSL
ETSI
12 ETSI TS 101 952-3 V1.1.1 (2012-02)
Z The input impedance of the splitter or filter at the ringing frequencies
InRing
Z Generic name of the load impedance, e.g. in the Figures in Clause 5.4.6 on RL test set-up
LOAD
Z Generic name of the POTS ON-hook impedance
ON
Z Impedance modelling POTS On-hook with High Impedance
OnHI
Z Impedance modelling multiple parallel on-hook phones
OnHo
Z Impedance modelling POTS On-hook with Low Impedance
OnLI
Z European harmonized complex reference POTS impedance
R
Z Generic name of Reference POTS impedance in RL formula in Clause 5.4.5
Ref
Z Nominal Reference Design Impedance of xDSL (Z ≡ R )
RefDSL RefDSL DSL
Z Complex POTS impedance, extending Z to higher frequencies, see TR 102 139 [i.1]
RHF R
Z Impedance modelling the load represented by ringer circuits
Ring
Z Impedance Z Short Loop, modelling a short line terminated on 600 Ω
SL
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
ADSL Asymmetric Digital Subscriber Line
ADSL1 Asymmetric Digital Subscriber Line 1
NOTE: ADSL limited to 1,1 MHz; specified in ITU Recommendation G.992.1 [i.9].
ADSL2 Asymmetric Digital Subscriber Line 2
NOTE: Revised in ITU-T Recommendation G.992.3 [i.10].
ADSL2plus ADSL2 "Plus"
NOTE: ADSL extended to 2,2 MHz; specified in ITU-T Recommendation G.992.5 [i.11].
CLI Calling Line Identification
CLIP Calling Line Identification Presentation
CMRR Common Mode Rejection Ratio
CO Central Office (≡ Local Exchange ≡ LE)
CM Common mode
CRC Cycle Redundancy Check
DC Direct Current
DS Downstream, i.e. LE to TE side
...