Information technology — Generic cabling systems for customer premises — Part 9903: Matrix modelling of channels and links

ISO/IEC 11801-9903:2021 (E) establishes a matrix-model for formulating limits for mixed mode parameters within and between two pairs of balanced cabling. This is for the purpose of supporting new, improved balanced cabling channel and link specifications.

Technologies de l'information — Câblage générique des locaux d'utilisateurs — Partie 9903: Modelage de la matrice des canaux et liens

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ISO/IEC TS 11801-9903
Edition 1.0 2021-03

Information technology – Generic cabling systems for customer premises –
Part 9903: Matrix modelling of channels and links

ISO/IEC TS 11801-9903:2021-03(en)

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ISO/IEC TS 11801-9903

Edition 1.0 2021-03





Information technology – Generic cabling systems for customer premises –

Part 9903: Matrix modelling of channels and links




ICS 35.200 ISBN 978-2-8322-9498-7

  Warning! Make sure that you obtained this publication from an authorized distributor.

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– 2 – ISO/IEC TS 11801-9903:2021
 ISO/IEC 2021
1 Scope . 9
2 Normative references . 9
3 Terms, definitions and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Symbols and abbreviated terms . 10
4 Matrix model . 11
5 Matrix definition . 11
5.1 General . 11
5.2 Quadriports . 11
5.3 Matrix port definition for a two-pair system representative for modelling
purposes . 11
5.4 Operational scattering matrix . 12
5.5 General naming convention. 12
5.6 S-matrix . 13
5.7 Passivity . 13
5.8 Operational reflection loss matrix . 14
5.9 Transmission matrix (T-matrix) . 14
5.10 S-matrix of cabling . 14
6 Calculation with matrices using limit lines . 15
7 Extracting limit lines . 15
8 General case using mixed-mode matrices. 16
8.1 General . 16
8.2 M-parameters . 16
9 Submatrix DD . 17
9.1 General . 17
9.2 Equations to extract the cabling limit lines . 17
9.2.1 General . 17
9.2.2 Operational attenuation . 17
9.2.3 Near-end crosstalk . 17
9.2.4 Attenuation to far-end crosstalk ratio . 17
9.2.5 Reflection (RL) . 18
10 Component values to be used as input to the model . 18
10.1 General . 18
10.2 Cable . 19
10.2.1 General . 19
10.2.2 Wave attenuation . 19
10.2.3 Near-end crosstalk . 19
10.2.4 Far-end crosstalk . 19
10.2.5 Reflection . 20
10.3 Connections . 21
10.3.1 General . 21
10.3.2 As a point source of disturbance . 21
10.3.3 As a transmission line . 21
11 Submatrices CC, CD and DC . 22

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ISO/IEC TS 11801-9903:2021 – 3 –
 ISO/IEC 2021
11.1 General . 22
11.2 Submatrix CD . 22
11.3 Submatrix DC . 22
11.4 Submatrix CC . 22
Annex A (informative) Matrix conversion formulas . 23
A.1 Overview. 23
A.2 Formulas. 23
A.2.1 Mixed-mode to T-matrix . 23
A.2.2 T-matrix to M-matrix . 23
A.2.3 Conversion matrices . 23
Annex B (normative) Channel and permanent link models for balanced cabling . 25
B.1 General . 25
B.2 Insertion loss . 25
B.2.1 Insertion loss of the channel configuration . 25
B.2.2 Insertion loss of the permanent link configurations . 26
B.2.3 Assumptions for insertion loss . 26
B.3 NEXT . 27
B.3.1 NEXT of the channel configuration . 27
B.3.2 NEXT of the permanent link configurations . 27
B.3.3 Assumptions for NEXT . 28
B.4 ACR-F . 31
B.4.1 ACR-F of the channel configuration . 31
B.4.2 ACR-F for the permanent link configurations . 31
B.4.3 Assumptions for ACR-F . 32
B.5 No Return loss . 32
B.5.1 Return loss of the channel and permanent link configurations . 32
B.5.2 Assumptions for the return loss circuit analysis method . 33
B.6 PS ANEXT link modelling . 36
B.6.1 General . 36
B.6.2 PS ANEXT between connectors . 36
B.6.3 PS ANEXT between cable segments . 36
B.6.4 Principles of link modelling . 36
B.7 PS AACR-F link modelling . 37
B.7.1 General . 37
B.7.2 PS AFEXT between connectors . 37
B.7.3 PS AACR-F between cable segments . 37
B.7.4 Principles of link modelling . 37
B.7.5 Impact of PS AACR-F in channels and links with substantially different
lengths . 38
B.8 Component assumptions for modelling purposes. 41
Annex C (informative) Terms and definitions . 43
C.1 Comparison of namings . 43
C.2 General . 44
C.3 Background of terms and definitions . 44
C.3.1 Operational attenuation . 44
C.3.2 Operational transfer function (T ) . 46
C.3.3 Image or wave transfer function (T) . 46
C.3.4 Insertion transfer function of a two-port (T ) . 46

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C.3.5 Insertion transfer function (T ) measured with a vector network
analyser . 46
C.3.6 Operational reflection loss transfer function (T = S ) of a junction . 46
ref ref
Bibliography . 48

Figure 1 – Link configurations of ISO/IEC 11801-1 . 7
Figure 2 – Matrix definition of a 4-port two twisted pair system . 12
Figure 3 – Operational scattering parameters example from port 2 . 12
Figure 4 – Transmission matrix concatenation showing an example of a 2-connector
permanent link . 14
Figure 5 – Graphical example of a NEXT calculation showing statistical results (red)

and final calculation (blue) . 16
Figure 6 – One pair M-matrix showing the submatrices . 16
Figure 7 – 100 m cable return loss without reflection at both ends . 20
Figure 8 – 100 m cable return loss with a reflection of 0,03 at both ends (6 Ω
mismatch, ~23 dB return loss at 1 MHz) . 21
Figure A.1 – X matrices . 24
Figure B.1 – Example of computation of NEXT with higher precision . 28
Figure B.2 – Example of increased impact of PS AFEXT . 38
Figure C.1 – Defining the operational attenuation and the operational transfer functions
of a two-port . 45
Figure C.2 – Defining the reflection transfer functions and the return loss of a junction . 47

Table 1 – All four ports operational scattering parameter definition . 12
Table 2 – Equal S-parameters for real components . 13
Table B.1 – Insertion loss deviation . 26
Table B.2 – Modelling assumptions for cable transmission parameters . 41
Table B.3 – Model input assumptions used in the statistical calculation (Class E ) . 41
Table B.4 – Model input assumptions used in the statistical calculation (Class F ) . 42
Table C.1 – Comparison of naming in ISO/IEC 11801-1 and ISO/IEC TS 11801-9903 . 43

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ISO/IEC TS 11801-9903:2021 – 5 –
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Part 9903: Matrix modelling of channels and links

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8) Attention is drawn to the Normative references cited in this document. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this ISO/IEC document may be the subject of
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ISO/IEC TS 11801-9903 has been prepared by subcommittee 25: Interconnection of information
technology equipment, of ISO/IEC joint technical committee 1: Information technology. It is a
Technical Specification.
This first edition of ISO/IEC TS 11801-9903 cancels and replaces ISO/IEC TR 11801-9903
published in 2015. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
a) the addition of further clarifications of the relations of parameters described in this edition
and referenced analogous parameters in IEC TR 62152, e.g. operational attenuation versus
operational transfer loss;
b) the introduction and description of the higher order M-parameters 8 × 8 matrix of mixed-
mode parameters, which includes the 4 × 4 submatrix of 4-port differential-mode-to-
differential-mode (DD) parameters, among three other submatrices of mixed-mode
c) Annex A, matrix conversion formulas, covers up to 16-port parameters matrices;
d) the expanded Annex B description of example calculations for channel and permanent link,
and updated component parameter tables.

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 ISO/IEC 2021
The list of all currently available parts of the ISO/IEC 11801 series, under the general title
Information technology – Generic cabling for customer premises, can be found on the IEC and
ISO web sites.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
JTC1-SC25/2959/DTS JTC1-SC25/2993/RVDTS

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1, available at

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

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ISO/IEC TS 11801-9903:2021 – 7 –
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The pass/fail limits for defined channel and permanent link cabling configurations have an
implicit impact on the component limits for the cabling components used. The channel
configurations and the link configurations are specified in ISO/IEC 11801-1:2017, Clause 6 and
Clause 7, respectively.
The permanent link configurations, which represent the fixed portion of the cabling, have two
possible topologies:
– a connection plus a segment of cable plus a connection (2-connector topology);
– a connection plus a segment of cable plus a connection plus another segment of cable plus
another connection (3-connector topology).
The link configurations of ISO/IEC 11801-1 are shown in Figure 1.

a) Configuration PL1

b) Configuration PL2

c) Configuration PL3

d) Configuration CP1

Figure 1 – Link configurations of ISO/IEC 11801-1
This document includes models and assumptions, which support pass/fail limits for the channel
and permanent link test configurations in ISO/IEC 11801-1. These are based on the
performance requirements of cable and connecting hardware as specified in IEC standards.
This document provides reasonable assurance that a channel created by adding compliant
patch cords to a previously certified permanent link will meet the applicable channel
performance limits.

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Over the years the frequencies of the classes increased, but the theory for calculating the limits
stayed the same. Especially the higher order effects had to be considered and in the end only
by doing a Monte Carlo calculation, assuming that not all components would be at the limit at
the same time, allowed compliance to be proved.
The model uses two pairs for all calculations. The limits are equal for pairs or pair combinations
but in reality measured values could be different. If results are required that need more pairs to
be considered, then this calculation can be done based on the results from multiple two-pair
calculations with appropriate inputs (worst case). An example of such a calculation is the power
sum and average limit lines for four pairs.
Symmetry and additional contributions that result from unbalanced signals and differential-to-
common and common-to-differential mode coupling are included in this document by increasing
the matrix size.
For details on the naming of transmission parameters, see Clause 3 and Clause C.1.

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ISO/IEC TS 11801-9903:2021 – 9 –
 ISO/IEC 2021

Part 9903: Matrix modelling of channels and links

1 Scope
This part of ISO/IEC 11801, which is a Technical Specification, establishes a matrix-model for
formulating limits for mixed-mode parameters within and between two pairs of balanced cabling.
This is for the purpose of supporting new, improved balanced cabling channel and link
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
ISO/IEC 11801-1, Information technology – Generic cabling for customer premises – Part 1:
General requirements
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 11801-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
• IEC Electropedia: available at
• ISO Online browsing platform: available at
diminishing of signal strength
Note 1 to entry: Details need to be added to indicate the exact usage.
two mated connectors
EXAMPLE Jack and plug.
image attenuation
wave attenuation
attenuation when a two-port is terminated by its input and output characteristic impedances with
no reflections at input and output
Note 1 to entry: The wave attenuation of cables is length scalable.

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insertion loss
attenuation or loss caused by a two-port inserted into a system
insertion loss deviation
deviation of attenuation loss with regard to the wave attenuation due to mismatches or internal
operational attenuation
ratio of the square root of the maximum available power wave vector emitted by the generator
and the square root of the power wave vector absorbed by the load of the two-port
Note 1 to entry: The operational attenuation is not length scalable (see also C.3.1 and C.3.2).
Note 2 to entry: The operational attenuation is expressed in decibels (dB) and radians (rad).
property of an electrical system that the output power at all ports does not exceed the input
power at all ports
mathematical concept for matrices to define passivity
operational reflection
loss due to the reflection at a junction
Note 1 to entry: See also C.3.6.
3.2 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviated terms given in ISO/IEC 11801-
1 and the following apply.
f frequency (MHz)
RL return loss limit (dB)
ρ (rho) operational reflection transfer function, junction reflection coefficient
DRL distributed return loss (dB)
IL insertion loss limit (dB)
A operational wave attenuation (Np)
A operational wave transfer function (Np)
B operational phase (rad)
B operational phase transfer function (rad)
B random phase (rad)
NEXT operational near-end crosstalk loss limit (dB)
NEXT operational near-end crosstalk transfer function (dB)
FEXT operational far-end crosstalk loss limit (dB)
FEXT operational far-end crosstalk transfer function (dB)

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ISO/IEC TS 11801-9903:2021 – 11 –
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4 Matrix model
The model to be used is a concatenated matrix calculation as discussed in IEC TR 62152 [1]
for a 2-port system. For a 2-pair balanced cabling calculation, a 4-port differential matrix as
shown in Figure 2 shall be used.
The model assumes that all components are specified with S-paramet

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