IEC 61156-5:2020

IEC 61156-5 ®
Edition 3.0 2020-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Multicore and symmetrical pair/quad cables for digital communications –
Part 5: Symmetrical pair/quad cables with transmission characteristics
up to 1 000 MHz – Horizontal floor wiring – Sectional specification

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IEC 61156-5 ®
Edition 3.0 2020-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Multicore and symmetrical pair/quad cables for digital communications –

Part 5: Symmetrical pair/quad cables with transmission characteristics

up to 1 000 MHz – Horizontal floor wiring – Sectional specification

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.120.20 ISBN 978-2-8322-8147-5

– 2 – IEC 61156-5:2020 RLV © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Installation considerations . 8
4.1 General remarks . 8
4.2 Bending radius of installed cable. 8
4.3 Climatic conditions . 8
5 Materials and cable construction . 8
5.1 General remarks . 9
5.2 Cable construction . 9
5.2.1 Conductor . 9
5.2.2 Insulation . 9
5.2.3 Cable element . 9
5.2.4 Cable make-up . 9
5.2.5 Screening of the cable core . 9
5.2.6 Sheath . 9
5.2.7 Identification . 10
5.2.8 Finished cable . 10
6 Characteristics and requirements . 10
6.1 General remarks . 10
6.2 Electrical characteristics and tests . 10
6.2.1 Conductor resistance . 10
6.2.2 Resistance unbalance. 11
6.2.3 Dielectric strength . 11
6.2.4 Insulation resistance . 11
6.2.5 Mutual capacitance . 11
6.2.6 Capacitance unbalance . 11
6.2.7 Transfer impedance . 11
6.2.8 Coupling attenuation . 12
6.2.9 Current-carrying capacity . 13
6.3 Transmission characteristics . 13
6.3.1 Velocity of propagation (phase velocity) . 13
6.3.2 Phase delay and differential delay (delay skew) . 13
6.3.3 Attenuation (α) . 14
6.3.4 Unbalance attenuation (TCL) . 15
6.3.5 Near-end crosstalk (NEXT) . 16
6.3.6 Far-end crosstalk (FEXT ACR-F) . 16
6.3.7 Alien (exogenous) near-end crosstalk (ANEXT) . 17
6.3.8 Alien (exogenous) far-end crosstalk (AFEXT AACR-F) . 17
6.3.9 Alien (exogenous) crosstalk of bundled cables . 17
6.3.10 Impedance . 17
6.3.11 Return loss (RL) . 17
6.4 Mechanical and dimensional characteristics and requirements . 20
6.4.1 Dimensional requirements . 20
6.4.2 Elongation at break of the conductors . 20

6.4.3 Tensile strength of the insulation . 20
6.4.4 Elongation at break of the insulation . 20
6.4.5 Adhesion of the insulation to the conductor . 20
6.4.6 Elongation at break of the sheath . 20
6.4.7 Tensile strength of the sheath . 20
6.4.8 Crush test of the cable . 20
6.4.9 Impact test of the cable . 20
6.4.10 Bending under tension . 20
6.4.11 Repeated bending of the cable . 20
6.4.12 Tensile performance of the cable . 20
6.4.13 Shock-test requirements of the cable . 20
6.4.14 Bump-test requirements of the cable . 21
6.4.15 Vibration-test requirements of the cable . 21
6.5 Environmental characteristics . 21
6.5.1 Shrinkage of insulation . 21
6.5.2 Wrapping test of insulation after thermal ageing . 21
6.5.3 Bending test of insulation at low temperature . 21
6.5.4 Elongation at break of the sheath after ageing . 21
6.5.5 Tensile strength of the sheath after ageing . 21
6.5.6 Sheath pressure test at high temperature . 21
6.5.7 Cold bend test of the cable . 21
6.5.8 Heat shock test . 21
6.5.9 Damp heat steady state . 21
6.5.10 Solar radiation (UV test) . 21
6.5.11 Solvents and contaminating fluids . 22
6.5.12 Salt mist and sulphur dioxide . 22
6.5.13 Water immersion . 22
6.5.14 Hygroscopicity . 22
6.5.15 Wicking. 22
6.5.16 Flame propagation characteristics of a single cable . 22
6.5.17 Flame propagation characteristics of bunched cables . 22
6.5.18 Halogen gas evolution . 22
6.5.19 Smoke generation . 22
6.5.20 Toxic gas emission . 22
6.5.21 Integrated fire test . 22
7 Category 5e multipair cable . 22
7.1 General . 22
7.2 Transmission . 23
8 Introduction to the blank detail specification . 23
Annex A (informative) Acronyms for common cable constructions .
Annex A (informative) Blank detail specification . 26
Bibliography . 31

Figure 1 – Impedance template .
Figure A.1 – Common cable construction examples .

Table 1 – Cable categories . 7
Table 2 – Transfer impedance . 12

– 4 – IEC 61156-5:2020 RLV © IEC 2020
Table 3 – Coupling attenuation in dB . 13
Table 4 – Attenuation equation constants . 14
Table 5 – Near-end unbalance attenuation . 15
Table 6 – Worst-pair PS NEXT(1) values . 16
Table 7 – Worst-pair PS EL FEXT ACR-F (1) values . 16
Table 8 – PS ANEXT . 17
Table 9 – PS AACR-F . 17
Table 10 – Return loss . 19
Table A.1 – Cable construction acronyms .

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES
FOR DIGITAL COMMUNICATIONS –
Part 5: Symmetrical pair/quad cables with transmission
characteristics up to 1 000 MHz – Horizontal floor wiring –
Sectional specification
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

– 6 – IEC 61156-5:2020 RLV © IEC 2020
International Standard IEC 61156-5 has been prepared by subcommittee 46C: Wires and
symmetric cables, of IEC technical committee 46: Cables, wires, waveguides, RF connectors,
RF and microwave passive components and accessories.
This third edition cancels and replaces the second edition published in 2009 and
Amendment 1:2012. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) additional balance levels with respect to MICE implementation by certain cabling
specifications;
b) reference to current standards and technical reports with respect to measurement
techniques and remote powering.
The text of this International Standard is based on the following documents:
FDIS Report on voting
46C/1140/FDIS 46C/1144/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
This International Standard is to be used in conjunction with IEC 61156-1:2007 and
IEC 61156-1:2007/AMD1:2009.
A list of all parts in the IEC 61156 series, published under the general title Multicore and
symmetrical pair/quad cables for digital communications, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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.
MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES
FOR DIGITAL COMMUNICATIONS –
Part 5: Symmetrical pair/quad cables with transmission
characteristics up to 1 000 MHz – Horizontal floor wiring –
Sectional specification
1 Scope
This part of IEC 61156 describes the cables intended primarily for horizontal floor wiring as
defined in ISO/IEC 11801 (all parts).
It covers cable designs comprising individually screened, common screened and unscreened
pairs or quads (see Annex A). The transmission characteristics and the frequency range (see
Table 1) of the cables are specified at 20 °C.
Table 1 – Cable categories
Maximum referenced
Cable designation frequency
MHz
Category 5e 100
Category 6 250
Category 6 500
A
Category 7 600
Category 7 1 000
A
These cables can be used for various communication channels which use as many as four
pairs simultaneously. In this sense, this document provides the cable characteristics required
by system developers to evaluate new systems.
The cables covered by this document are intended to operate with voltages and currents
normally encountered in communication systems. While these cables are not intended to be
used in conjunction with low impedance sources, for example the electric power supplies of
public utility mains, they are intended to be used to support the delivery of low voltage and
remote powering applications such as IEEE 802.3af (Power over Ethernet) and or further
developments for example according to IEEE 802.3at (Power over Ethernet Plus) or IEEE
802.3bt. More information on the capacity to support these applications according to the
installation practices are given in IEC 61156-1-4, IEC TR 61156-1-6 and ISO/IEC TS 29125.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 61156-1:2007, Multicore and symmetrical pair/quad cables for digital communications –
Part 1: Generic specification
IEC 61156-1:2007/AMD1:2009
– 8 – IEC 61156-5:2020 RLV © IEC 2020
IEC 61156-5-1, Multicore and symmetrical pair/quad cables for digital communications –
Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz – Horizontal
floor wiring – Blank detail specification
IEC 62153-4-3, Metallic communication cables test methods – Part 4-3: Electromagnetic
compatibility (EMC) – Surface transfer impedance – Triaxial method
IEC 62153-4-5, Metallic communication cables test methods – Part 4-5: Electromagnetic
compatibility (EMC) – Coupling or screening attenuation – Absorbing clamp method
IEC 62153-4-9, Metallic communication cable test methods – Part 4-9: Electromagnetic
compatibility (EMC) – Coupling attenuation of screened balanced cables, triaxial method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61156-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Installation considerations
4.1 General remarks
Installation considerations are defined in IEC 61156-1:2007, Clause 4.
4.2 Bending radius of installed cable
The bending radius of the installed cable shall not be less than four times the outside
diameter of the cable.
4.3 Climatic conditions
Under static conditions, the cables shall operate in the temperature range from –40 °C to
+60 °C. The conductor and cable temperature dependence is specified for screened and
unscreened cables and should be taken into account for the design of an actual cabling
system.
Other temperature ranges may be specified in the relevant detail specification.
Under static conditions, the cable shall operate at least in the temperature range of the
environment from –20 °C to +60 °C.
The attenuation increase due to the elevated operating temperature (temperature of the
environment) is described in 6.3.3.3.
In the case of application of remote powering, the maximum temperature of the conductor
shall not exceed the maximum operation temperature under static conditions in order to
maintain the integrity of the dielectric material performance which is aligned to the
environmental temperature range.
Extended temperature ranges are permitted and may be specified in the relevant detail
specification.
5 Materials and cable construction
5.1 General remarks
The choice of materials and cable construction shall be suitable for the intended application
and installation of the cable. Particular care shall be taken to meet any requirements for EMC
and fire performance (such as burning properties, smoke generation, evolution of halogen gas,
etc.).
The cable construction shall be in accordance with the details and dimensions given in the
relevant detail specification.
5.2 Cable construction
5.2.1 Conductor
The conductor shall be a solid annealed copper conductor, in accordance with
IEC 61156-1:2007, 5.2.1 and should have a nominal diameter between 0,4 mm and 0,65 mm.
A conductor diameter of up to 0,8 mm may be used.
5.2.2 Insulation
The conductor shall be insulated with a suitable material. Examples of suitable materials are:
– polyolefin;
– fluoropolymer;
– low-smoke zero-halogen thermoplastic material.
The diameter of the insulated conductor shall be indicated in the relevant detail specification.
5.2.3 Cable element
5.2.3.1 General
The cable element shall be a twisted pair or quad.
5.2.3.2 Screening of the cable element
When required, the screen for the cable element shall be in accordance with
IEC 61156-1:2007, 5.2.3.2.
5.2.4 Cable make-up
A spacer may be used to separate the cable elements. The cable elements, including spacers,
shall be assembled to form the cable core.
The core of the cable may be wrapped with a protective layer of non-hygroscopic and non-
wicking material.
5.2.5 Screening of the cable core
When required by the relevant detail specification, a screen for the cable core shall be
provided.
The screen shall be in accordance with IEC 61156-1:2007, 5.2.5.
5.2.6 Sheath
The sheath material shall consist of a suitable material.

– 10 – IEC 61156-5:2020 RLV © IEC 2020
Examples of suitable materials are:
– polyolefin;
– PVC;
– fluoropolymer;
– low-smoke zero-halogen thermoplastic material.
The sheath shall be continuous, having a thickness as uniform as possible. A non-metallic
ripcord may be provided. When provided, the ripcord shall be non-hygroscopic and non-
wicking.
The colour of the sheath is not specified but should be specified in the relevant detail
specification.
5.2.7 Identification
Each length of cable shall be identified with the supplier's details, and when required, by
means of a traceability code, using one of the following methods:
a) appropriately coloured threads or tapes;
b) with a printed tape;
c) printing on the cable core wrapping;
d) marking on the sheath.
Additional markings, such as length marking, etc. are permitted. If used, such markings
should be indicated in the relevant detail specification.
5.2.8 Finished cable
The finished cable shall be adequately protected for storage and shipment.
6 Characteristics and requirements
6.1 General remarks
Clause 6 lists the characteristics and minimum requirements of a cable complying with this
document. Test methods shall be in accordance with IEC 61156-1:2007 and
IEC 61156-1:2007/AMD1:2009, Clause 6.
The tests according to 6.2 shall be carried out on a cable length of not less than 100 m,
unless otherwise specified.
All the tests according to 6.3 shall be carried out on a cable length of 100 m, unless otherwise
specified. If suitable, respective lengths correction formulas according to IEC 61156-1 shall
be used. For Category 7 , unless the test is performed with very sensitive test equipment, it is
A
recommended to limit the cable length to 50 m for a better accuracy in high frequencies.
In case balunless measurements are made, the procedures should be as per
IEC TR 61156-1-2:2009 and IEC TR 61156-1-2:2009/AMD1:2014 which covers the application
of balunless measurement technology.
6.2 Electrical characteristics and tests
The tests shall be carried out on a cable length of not less than 100 m, unless otherwise
specified.
NOTE For cat7A, unless the test is performed with very sensitive test equipment, it is recommended to limit the
cable length to 50 m for a better accuracy in high frequencies.
6.2.1 Conductor resistance
The maximum conductor resistance at or corrected to 20 °C shall not exceed 9,5 Ω for 100 m
of cable.
6.2.2 Resistance unbalance
6.2.2.1 Resistance unbalance within a pair
The resistance unbalance shall not exceed 2,0 %.
6.2.2.2 Resistance unbalance between pairs
The pair-to-pair resistance unbalance shall not exceed 4 % 5,0 %.
6.2.3 Dielectric strength
There shall be no failures when a test is performed on a conductor/conductor and, where
screen(s) are present, on a conductor/screen with 1,0 kV DC for 1 min or, alternately, with
2,5 kV DC for 2 s. An AC voltage may be used. The AC voltage levels in these cases shall be
0,7 kV AC for 1 min or, alternately, 1,7 kV AC for 2 s.
6.2.4 Insulation resistance
The test shall be performed both on
– conductor/conductor;
– conductor/screen (when present).
The minimum insulation resistance at or corrected to 20 °C shall be not less than 5 000 MΩ·m
5 000 MΩ · km.
6.2.5 Mutual capacitance
The mutual capacitance is not specified but may be indicated in the relevant detail
specification.
6.2.6 Capacitance unbalance
The maximum capacitance unbalance pair to ground shall not exceed 1 600 pF/km at a
frequency of 800 Hz or 1 000 Hz.
6.2.7 Transfer impedance
For cables containing a screen or screens, two grades of performance are recognized for
transfer impedance. The transfer impedance measured according to IEC 62153-4-3 shall not
exceed the values shown in Table 2 at the discrete frequencies indicated for each grade.

– 12 – IEC 61156-5:2020 RLV © IEC 2020
Table 2 – Transfer impedance
Frequency Maximum surface transfer impedance
MHz mΩ/m
Grade 1 Grade 2
1 10 50
10 10 100
30 30 200
100 100 1 000
Maximum surface transfer impedance
Frequency range
mΩ/m
MHz
Grade 1 Grade 2
-0,176 0,301
1 to 10 Z ≤ 15 × f Z ≤ 50 × f
t t
0,6309
10 to 30 Z ≤ 10 × f/10 Z ≤ 23,392 × f
t t
1,3368
30 to 100 Z ≤ 10 × f/10 Z ≤ 2,1206 × f
t t
NOTE The screen longitudinal DC resistance of 30 mΩ/m or less is an indicator for fulfilling the transfer
impedance requirement of Grade 2. A measurement of DC resistance cannot replace a transfer impedance
measurement.
6.2.8 Coupling attenuation
Three Four types of performance are recognized for coupling attenuation. When measured
using the absorbing clamp method (IEC 62153-4-5) or the triaxial method (IEC 62153-4-9),
the coupling attenuation in the frequency range from f = 30 MHz to 1 000 MHz shall meet the
requirements indicated in Table 3. For screened cables the triaxial method (IEC 62153-4-9)
may also be used, Type II is the minimum coupling attenuation requirement.

Table 3 – Coupling attenuation in dB
Coupling attenuation type Frequency range Coupling attenuation
MHz dB
30 – 100
≥ 85
Type I
100 – 1 000
≥ 85 – 20 × log (f /100)
30 – 100 ≥55
Type II
100 – 1 000 ≥ 55 – 20 × log (f /100)
30 – 100
≥40
Type III
100 – 1 000 ≥ 40 – 20 × log (f /100)
Frequency range
Coupling attenuation type
MHz
30 to 100 100 to 1 000
Type I ≥ 85 ≥ 85 – 20 × log (f /100)
Type Ib ≥ 70 ≥ 70 – 20 × log (f /100)
Type II ≥ 55 ≥ 55 – 20 × log (f /100)
Type III ≥ 40 ≥ 40 – 20 × log (f /100)
6.2.9 Current-carrying capacity
The maximum current-carrying capacity is not specified but may be indicated in the relevant
detail specification. Further guidance with respect to current carrying capacity is provided by
ISO/IEC TS 29125 and the test method described in IEC 61156-1-4.
6.3 Transmission characteristics
All the tests shall be carried out on a cable length of 100 m, unless otherwise specified.
6.3.1 Velocity of propagation (phase velocity)
The requirement is not specified but may be indicated in the relevant detail specification.
6.3.2 Phase delay and differential delay (delay skew)
6.3.2.1 Phase delay
τ
The phase delay, , shall not exceed the value obtained from Equation (1) in the frequency
range from 4 MHz to the maximum referenced frequency.
τ = 534 + (1)
f
where
τ is the phase delay in ns/100 m;
f is the frequency expressed in MHz.

– 14 – IEC 61156-5:2020 RLV © IEC 2020
6.3.2.2 Differential delay (delay skew)
When the delay is measured at (20 ± 1 20 ± 3) °C, the maximum delay skew between any two
pairs at a given temperature shall be not greater than 45 ns/100 m for Category 5e,
Category 6 and Category 6 cables and 25 ns/100 m for Category 7 and Category 7 cables
A A
in the frequency range from 4 MHz to the maximum referenced frequency.
6.3.3 Attenuation (α)
6.3.3.1 Attenuation at 20 °C operating temperature
The maximum attenuation, α, of any pair in the frequency range indicated in Table 4 shall not
exceed the value obtained from Equation (2).
c
α a ff++b (2)
f
where
α is the attenuation expressed in dB/100 m;
a, b, c are constants indicated in Table 4;
f is the frequency expressed in MHz.
Table 4 – Attenuation equation constants
Constants
Frequency range
Cable designation
MHz
a b c
Category 5e 1 to 100 1,967 0,023 0,100
Category 6 1 to 250 1,820 0,016 9 0,250
Category 6 1 to 500 1,820 0,009 1 0,250

A
Category 7 1 to 600 1,800 0,010 0,200
Category 7 1 to 1 000 1,800 0,005 0,250 0,240

A
The cable performance between 1 MHz and 4 MHz is achieved by design only and it is
therefore not necessary to test for this performance below 4 MHz.

6.3.3.2 Category 5e special consideration
The constants for Category 5e in Table 4 are based on the use of patch cables for work area
wiring having up to a 20 % higher attenuation than the horizontal cable. When patch cables
for work area wiring having an attenuation up to 50 % higher than the horizontal cable are
used, the constants should be 1,910 8, 0,022 2 and 0,200 for a, b and c respectively.
6.3.3.3 Attenuation at elevated operating temperature
The increase in of the maximum attenuation obtained from Equation (2) due to an elevated
environmental temperature above 20°C, shall be is obtained by calculation as follows:
– for unscreened cables: 0,4 %/°C, for the temperature range from 20 °C to 40 °C and
0,6 %/°C for the temperature range 40 °C to 60 °C.
– for screened cables: 0,2 %/°C in the temperature range 20 °C to 60 °C.
In the case of application of remote powering, the actual conductor temperature shall be
considered to calculate the attenuation increase. If an extended environmental temperature
range is specified (see 4.3) the temperature coefficients given in 6.3.3.3 might not be
=
applicable. The method provided in IEC 61156-1 shall be used to determine temperature
coefficients in this case.
6.3.4 Unbalance attenuation (TCL)
Two Four levels of performance are recognized for unbalance attenuation. The minimum near-
end unbalance attenuation (transverse conversion loss or TCL) shall not be less than the
value obtained from Equation (3) (Level 1) or from Equation (4) (Level 2) to Equation (6)
(Level 4), for all frequencies, f, in the frequency ranges indicated in Table 5.
Level 1: TCL 40,0−×10 log f (dB) (3)
( )
Level 2: TCL 50,0−×10 log ( f ) (dB) (4)
Level 3: TCL 60,0−×10 log f (dB) (5)
( )
Level 4: TCL 70,0−×10 log f (dB) (6)
( )
NOTE If the intention is to increase the frequency range of balance measurements, IEC TR 61156-1-2 provides
guidance on the respective (e.g. balunless) measurement techniques.
Table 5 – Near-end unbalance attenuation
Frequency range
Cable category
MHz
Category 5e 1 to 100
Category 6 1 to 250
Category 6 1 to 250
A
Category 7 1 to 250
Category 7 1 to 250
A
For those frequencies where the calculated value of TCL is greater than 50 dB, the
requirement shall be 50 dB. TCL requirements for frequencies higher than 250 MHz may be
defined in the detail specification.
The minimum equal-level far-end unbalance attenuation (equal-level transverse conversion
transfer loss or EL TCTL) for all categories shall not be less than the value obtained from
Equation (7) to Equation (9) for all frequencies, f, in the range from 1 MHz to 30 MHz.
Level 1, Level 2 EL TCTL 35,0− 20×log f (dB) (7)
( )
Level 3 EL TCTL 45,0− 20×log ( f ) (dB) (8)
Level 4 EL TCTL 55,0− 20×log f (dB) (9)
( )
For those frequencies where the calculated value of EL TCTL is greater than 40 dB, the
requirement shall be 40 dB. EL TCTL requirements for frequencies higher than 30 MHz may
be defined in the detail specification.
=
=
=
=
=
=
=
– 16 – IEC 61156-5:2020 RLV © IEC 2020
6.3.5 Near-end crosstalk (NEXT)
The worst pair power sum near-end crosstalk, PS NEXT, at all frequencies, f, in the frequency
range indicated in Table 6 shall not be less than the value obtained from Equation (10) using
the corresponding value of PS NEXT(1) indicated in Table 6.
PS NEXT(f) = PS NEXT(1) – 15 x log (f) (dB) (10)
Table 6 – Worst-pair PS NEXT(1) values
Frequency range PS NEXT(1)
Cable designation
MHz dB
Category 5e 1 to 100 62,3
Category 6 1 to 250 72,3
Category 6 1 to 500 72,3
A
Category 7 1 to 600 99,4
Category 7 1 to 1 000 102,4
A
NOTE The cable performance between 1 MHz and 4 MHz is achieved by design only
and it is therefore not necessary to test for this performance below 4 MHz.

For those frequencies where the calculated value of PS NEXT is greater than 75 dB, the
requirement shall be 75 dB.
The minimum pair-to-pair NEXT for any pair combination shall be at least 3 dB better than the
PS NEXT for any pair.
6.3.6 Far-end crosstalk (FEXT ACR-F)
The worst-pair power-sum equal-level far-end crosstalk, PS EL FEXT ACR-F, at all frequencies,
f, in the frequency range indicated in Table 7 shall not be less than the value obtained from
Equation (11) using the corresponding value of PS EL FEXT ACR-F (1) given in Table 7.
( ) ( ) ( )
PS EL FEXT f = PS EL FEXT 1 − 20 ×log f
PS ACR− F f PS ACR− F 1− 20×log f (dB) (11)
( ) ( ) ( )
Table 7 – Worst-pair PS EL FEXT ACR-F (1) values
Frequency range PS EL FEXT ACR-F(1)
Cable designation
MHz dB for 100 m
Category 5e 4 1 to 100 61,0
Category 6 4 1 to 250 65,0
Category 6 4 1 to 500 65,0
A
Category 7 4 1 to 600 91,0
Category 7 4 1 to 1 000 92,3
A
NOTE 1 If FEXT loss is greater than 90 dB, EL FEXT PS ACR-F loss may not be
calculated.
NOTE 2 The cable performance between 1 MHz and 4 MHz is achieved by design only
and it is therefore not necessary to test for this performance below 4 MHz.

=
For those frequencies where the calculated value of PS EL FEXT ACR-F is greater than 75 dB,
the requirement shall be 75 dB.
The minimum pair-to-pair EL FEXT ACR-F for any pair combination shall be at least 3 dB
better than the PS EL FEXT ACR-F for any pair.
6.3.7 Alien (exogenous) near-end crosstalk (ANEXT)
Alien (exogenous) near-end crosstalk, ANEXT, is only a measurement consideration for
Type III cables according to 6.2.8. For Type I, Type Ib and Type II screened cables as defined
in Table 3, ANEXT is proven by design.
The PS ANEXT (power sum alien (exogenous) near-end crosstalk) of cable when tested in
accordance with IEC 61156-1:2007, 6.3.7.1 shall be not less than the values obtained from
Table 8.
Table 8 – PS ANEXT
Category Frequency range Minimum PS ANEXT
MHz dB
Category 6 1 ≤ f ≤ to 500 92,5 – 15 × log (f)
A 10
Category 7 107,5 – 15 × log (f)
1 ≤ f ≤ to 1 000
A 10
NOTE Calculated values greater than 67 dB revert to a value of 67 dB.

6.3.8 Alien (exogenous) far-end crosstalk (AFEXT AACR-F)
Alien (exogenous) far-end crosstalk, AFEXT AACR-F, is only a measurement consideration for
unscreened cables. For Type I, Type Ib and Type II screened cables as defined in Table 3,
AFEXT AACR-F is proven by design.
The PS AACR-F (power-sum alien attenuation to crosstalk ratio far-end) of the cable when
tested in accordance with IEC 61156-1:2007, 6.3.8, shall not be less than the values obtained
from Table 9.
Table 9 – PS AACR-F
Category Frequency range Minimum PS AACR-F
MHz dB
Category 6 78,2 – 20 × log (f)
1 ≤ f ≤ to 500
A 10
Category 7 93,2 – 20 × log (f)
1 ≤ f ≤ to 1 000
A 10
NOTE Calculated values greater than 67 dB revert to a value of 67 dB.

6.3.9 Alien (exogenous) crosstalk of bundled cables
The minimum requirement is not specified but should be stated in the relevant detail
specification.
6.3.10 Impedance
The impedance requirement is specified by either case A or case B below as specified in the
relevant detail specification.
Case A (Fitted or mean characteristic impedance):

– 18 – IEC 61156-5:2020 RLV © IEC 2020
The impedance measured in accordance with 6.3.10.2 or 6.3.10.3 of IEC 61156-1 shall be
100 Ω ± 5 Ω at 100 MHz. In this case, the return loss shall also be measured.
Case B (Characteristic impedance):
The impedance measured in accordance with 6.3.10.1.1 of IEC 61156-1 shall fall within the
impedance template limits given in Figure 1. The relevant template limits are derived using
Equation (8) and Equation (9) for the corresponding cable category, frequency range and
return loss requirement given in Table 10.
Cables that meet the requirements of the template are not required to be measured for return
loss; alternately cables that meet the return loss requirements given in 6.3.11 are not required
to be measured for characteristic impedance.
The upper impedance limit, Zu of the template is given by Equation (8),
(1 + ρ )
Zu = Z ⋅ (8)
(1 − ρ )
The lower impedance limit, Zl of the template is given by Equation (9),
(1 − ρ )
Zl = Z ⋅ (9)
(1 + ρ )
where
Z is 100 Ω;
|ρ| is the reflection coefficient magnitude calculated from Equation (10),
R
...