ISO/IEC 11801-1:2017/Amd 1:2025
(Amendment)Information technology — Generic cabling for customer premises — Part 1: General requirements — Amendment 1
Information technology — Generic cabling for customer premises — Part 1: General requirements — Amendment 1
Technologies de l'information — Câblage générique des locaux d'utilisateurs — Partie 1: Titre manque — Amendement 1
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ISO/IEC 11801-1
Edition 1.0 2025-11
INTERNATIONAL
STANDARD
AMENDMENT 1
Information technology - Generic cabling for customer premises -
Part 1: General requirements
ICS 35.200 ISBN 978-2-8327- 0856-9
ISO/IEC 11801-1:2017-11/AMD1:2025-11(en)
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ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Information technology -
Generic cabling for customer premises -
Part 1: General requirements
AMENDMENT 1
FOREWORD
1) ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental,
in liaison with ISO and IEC, also take part in the work.
2) The formal decisions or agreements of IEC and ISO 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 and ISO National bodies.
3) IEC and ISO documents have the form of recommendations for international use and are accepted by IEC and
ISO National bodies in that sense. While all reasonable efforts are made to ensure that the technical content of
IEC and ISO documents is accurate, IEC and ISO 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 and ISO National bodies undertake to apply IEC and
ISO documents transparently to the maximum extent possible in their national and regional publications. Any
divergence between any IEC and ISO document and the corresponding national or regional publication shall be
clearly indicated in the latter.
5) IEC and ISO do not provide any attestation of conformity. Independent certification bodies provide conformity
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responsible for any services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this document.
7) No liability shall attach to IEC and ISO or their directors, employees, servants or agents including individual
experts and members of its technical committees and IEC and ISO National bodies 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 ISO/IEC document or any
other IEC and ISO documents.
8) Attention is drawn to the Normative references cited in this document. Use of the referenced publications is
indispensable for the correct application of this document.
9) IEC and ISO draw attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC and ISO take no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, IEC and ISO had not received notice of
(a) patent(s), which may be required to implement this document. However, implementers are cautioned that this
may not represent the latest information, which may be obtained from the patent database available at
https://patents.iec.ch and www.iso.org/patents. IEC and ISO shall not be held responsible for identifying any or
all such patent rights.
Amendment 1 to ISO/IEC 11801-1:2017 has been prepared by subcommittee 25:
Interconnection of information technology equipment, of ISO/IEC joint technical committee 1:
Information technology.
The text of this Amendment is based on the following documents:
Draft Report on voting
JTC1-SC25/3285/CDV JTC1-SC25/3337A/RVC
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 Amendment is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1, and the ISO/IEC Directives, JTC 1 Supplement
available at www.iec.ch/members_experts/refdocs and www.iso.org/directives.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
INTRODUCTION TO THE AMENDMENT
This document specifies single pair component Categories T1-A, T1-B, and T1-C, as well as
cabling channels and link Classes T1-A, T1-B, and T1-C to support single pair applications.
Balanced single pair channels and links specified in this document are not a replacement for
the generic 4-pair channels in ISO/IEC 11801-1:2017. They are an additional media type
intended for use in intelligent building and industrial automation devices (e.g. in network
sensors, actuators, and controllers). Because of the different types and locations of these
devices, single pair cabling will have distinct structures and distribution architectures that are
detailed in other parts of the ISO/IEC 11801 series.
This document also provides modifications and corrections to ISO/IEC 11801-1:2017.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
INTRODUCTION
Replace the existing Figure 1 with the following new figure:
Figure 1 – Relationships between the generic cabling documents
produced by ISO/IEC JTC 1/SC 25
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
1 Scope
Replace existing bullet b) with the following:
b) channel transmission, environmental and power delivery performance requirements;
2 Normative references
Add the following normative references at the end of the list:
IEC 60512-99-002, Connectors for electrical and electronic equipment - Tests and
measurements - Part 99-002: Endurance test schedules - Test 99b: Test schedule for unmating
under electrical load
IEC 61156-11, Multicore and symmetrical pair/quad cables for digital communications - Part 11:
Symmetrical single pair cables with transmission characteristics up to 1,25 GHz - Horizontal
floor wiring - Sectional specification
IEC 61156-12, Multicore and symmetrical pair/quad cables for digital communications - Part 12:
Symmetrical single pair cables with transmission characteristics up to 1,25 GHz - Work area
wiring - Sectional specification
IEC 61156-13, Multicore and symmetrical pair/quad cables for digital communications - Part 13:
Symmetrical single pair cables with transmission characteristics up to 20 MHz - Horizontal floor
wiring - Sectional specification
IEC 61156-14, Multicore and symmetrical pair/quad cables for digital communications - Part 14:
Symmetrical single pair cables with transmission characteristics up to 20 MHz - Work area
wiring - Sectional specification
IEC 61196-1-105, Coaxial communication cables - Part 1-105: Electrical test methods - Test for
withstand voltage of cable dielectric
IEC 61935-4, Specification for the testing of balanced and coaxial information technology
cabling - Part 4: Installed balanced single-pair cabling as specified in ISO/IEC 11801-1 and
related standards
IEC 63171, Connectors for electrical and electronic equipment - Shielded or unshielded free
and fixed connectors for balanced single-pair data transmission with current-carrying capacity -
General requirements and tests
IEC 63171-1, Connectors for electronic equipment - Part 1: Detail specification for two-way,
shielded or unshielded, free and fixed connectors - Mechanical mating information, pin
assignment and additional requirements for Type 1 copper LC style
IEC 63171-6, Connectors for electrical and electronic equipment - Part 6: Detail specification
for 2-way and 4-way (data/power), shielded, free and fixed connectors for power and data
transmission with frequencies up to 600 MHz
ISO/IEC TS 29125, Telecommunications cabling requirements for remote powering of terminal
equipment
___________
First edition under preparation. Stage at the time of publication: IEC CDV 61935-4:2025.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
3.2 Abbreviations
Add the following new abbreviations at the end of the list:
PON passive optical network
S-PoE single pair Power over Ethernet
SP single pair
SPE single pair Ethernet
5.3.1 Cabling subsystem 1
Replace the last paragraph with the following paragraph:
Although terminal equipment cords and equipment cords are used to connect terminal and
transmission equipment respectively to the cabling subsystem, they are not considered part of
the cabling subsystem because they can be application specific.
6 Channel performance requirements
6.3.3.4.1 General
Delete the existing second paragraph.
6.3.3.6 Direct current loop resistance
Replace the existing Table 17 with the following new Table 17:
Table 17 – DC loop resistance for a channel
a
DC loop resistance
b b
Class
Maximum DC loop resistance at 60 °C Informative DC loop resistance at 20 °C
Ω Ω
A 560 472
B 170 143,3
C 40 33,7
c e
D, E, E , F, F
25 21,1
A A
BCT-B-L 4,0 3,4
BCT-B-M 6,9 5,8
d f
I, II
6,4 5,4
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
a
This requirement is based on channels designed for the MICE C1 environmental classification.
b
The requirements at 20 °C and 60 °C are equivalent according to the generic formula for temperature
correction of resistance. To correct DC loop resistance to a different temperature, the conversion is as follows:
( )
R R [1+ α T− T ]
ref ref
where
R is conductor resistance at temperature T in Ω;
R is conductor resistance at reference temperature T , usually 20 °C, in Ω;
ref ref
α is temperature coefficient of resistance for the conductor material (copper = 0,003 93) per °C;
T is conductor temperature in °C;
T is reference temperature that α is specified at for the conductor material in °C.
ref
c
The maximum DC loop resistance at 60 °C of each pair of a cable (excluding connections) within a 2-connector
link used in a channel shall be 0,22 Ω/m. This shall be achieved by an appropriate design.
d
The maximum DC loop resistance at 60 °C of each pair of a cable (excluding connections) within a 2-connector
link used in a channel shall be 0,16 Ω/m. This shall be achieved by an appropriate design.
e
The maximum DC loop resistance at 20 °C of each pair of a cable (excluding connections) within a 2-connector
link used in a channel shall be 0,19 Ω/m. This shall be achieved by an appropriate design.
f
The maximum DC loop resistance at 20 °C of each pair of a cable (excluding connections) within a 2-connector
link used in a channel shall be 0,14 Ω/m. This shall be achieved by an appropriate design.
6.3.3.12.2 Unbalance attenuation, near-end
Replace the existing Table 22 with the following new Table 22:
Table 22 – Informative TCL values for unscreened channels at key frequencies
Minimum TCL
dB
Frequency Class
MHz A B C D E, E
A
E , E , E E , E , E E , E , E E E E E E E
1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
0,1 30,0 40,0 – – – – – – –
1 – 20,0 30,0 40,0 40,0 40,0 40,0 40,0 40,0
16 – – 24,0 34,9 40,0 40,0 34,9 40,0 40,0
30 – – – 30,8 40,0 40,0 30,8 40,0 40,0
100 – – – 20,3 30,3 40,0 20,3 30,3 40,0
250 – – – – – – 12,3 22,3 32,3
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
6.3.3.12.4 Coupling attenuation
Add the following sentence after the first sentence of the second paragraph:
The coupling attenuation of each pair of a channel, with maximum implementation, at key
frequencies is given in Table 145 for information only.
=
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Add the following new table below the existing Table 29:
Table 145 – Informative coupling attenuation values
for a screened channel at key frequencies
Minimum coupling attenuation
dB
Frequency Class
a
MHz
BCT-B I, II
D, E, E , F, F
A A
E E E E E E E E E
1 2 3 1 2 3 1 2 3
30 40,0 50,0 60,0 85,0 85,0 85,0 50,0 50,0 60,0
100 40,0 50,0 60,0 85,0 85,0 85,0 50,0 50,0 60,0
250 32,0 42,0 52,0 85,0 85,0 85,0 42,0 42,0 52,0
500 26,0 36,0 46,0 75,0 75,0 75,0 36,0 36,0 46,0
1 000 20,0 30,0 40,0 75,0 75,0 75,0 30,0 30,0 40,0
1 600 – – – – – – 25,9 25,9 35,9
2 000 – – – – – – 24,0 24,0 34,0
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
a
The informative values are applicable to the upper frequency of the Class.
6.3.3.13.6 Alien crosstalk and coupling attenuation for screened channels
Replace the existing Table 38 with the following new Table 38:
Table 38 – Alien crosstalk and coupling attenuation for screened channels
Minimum coupling attenuation to Minimum coupling attenuation
Class Frequency
meet PS ANEXT limits to meet PS AACR-F limits
MHz dB dB
30≤
50 50
E
A
100≤≤f 500 90− 20lg ( f ) 90− 20lg ( f )
30≤
50 50
F
100≤≤f 600 90− 20lg ( f ) 90− 20lg ( f )
30≤
65 65
F
A
100≤≤f 1 000 105− 20lg ( f ) 105− 20lg ( f )
30≤
65 65
I
100≤≤f 2 000 105− 20lg ( f ) 105− 20lg ( f )
30≤
65 65
II
100≤≤f 2 000 105− 20lg ( f ) 105− 20lg ( f )
6.5.2.1 Channel attenuation
Replace the first paragraph with the following:
For the purpose of specifying channel limits, the cable requirements of Table 92 and the
connecting hardware requirements of Table 136 shall be used.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Insert new subclause:
6.6 Single pair cabling transmission performance
6.6.1 General
This document specifies the following Classes for single pair balanced cabling:
a) Class T1-A is specified from 0,1 MHz to 20 MHz,
b) Class T1-B is specified from 0,1 MHz to 600 MHz,
c) Class T1-C is specified from 0,1 MHz to 1 250 MHz.
The insertion loss, PS AACR-F, ELTCTL and other length related parameter performance of
Class T1-A cabling is further subdivided into three sub-Classes, T1-A-100, T1-A-400, and
T1-A-1000. These sub-Classes have identical performance requirements for all other
transmission parameters. The numerical identifiers at the end of the T1-A sub-Classes refer to
the assumptions of maximum channel length from the reference implementation for data
transmission.
A Class T1-A channel is specified so that it will provide the minimum transmission performance
to support Class T1-A applications. Channels of a given Class will support all applications of a
lower Class with the same length. For example, a 100 m Class T1-B channel is backward
compatible to a 100 m Class T1-A channel. Annex E lists known single pair balanced cabling
applications by Class. Annex G lists possible channel length reductions required when remote
powering is applied. Additional information related to cable heating, installation environments
and cable bundling is given in ISO/IEC TS 29125.
The requirements in 6.6 are given by limits computed to one decimal place, using the equation
for a defined frequency range. The limits for the propagation delay and delay skew are
computed to three decimal places. The informative tables show the calculated values derived
from the relevant equation at key frequencies. Many specifications in 6.6 have a plateau in the
specified requirement. These plateaus do not accurately depict the system performance. They
have been added for measurement purposes.
6.6.2 Component choice
The parameters specified in 6.6 apply to channels with screened or unscreened cable elements
unless explicitly stated otherwise.
The nominal differential mode impedance of channels is 100 Ω. This is achieved by suitable
design and appropriate choice of cabling components (irrespective of their nominal impedance).
6.6.3 Channel parameters
6.6.3.1 Return loss
The return loss requirements are applicable to all single pair cabling Classes.
The return loss (RL) of a single pair channel shall meet the requirements in Table 146. The RL
values for a single pair channel at key frequencies are given in Table 147 for information only.
The return loss requirements shall be met at both ends of the cabling. Return loss (RL) values
at frequencies where the insertion loss (IL) is below 3,0 dB are for information only.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 146 – Return loss for a single pair channel
Class Frequency Minimum return loss
MHz dB
0,1 ≤ f < 0,5 9 + 8 (f)
T1-A
0,5 ≤ f ≤ 20 13,0
0,1 ≤ f < 1 9 + 10 (f)
1 ≤ f < 10 19,0
10 ≤ f < 40 24 − 5 lg(f)
T1-B
40 ≤ f < 130 16,0
130 ≤ f < 400 37 − 10 lg(f)
400 ≤ f ≤ 600 11,0
0,1 ≤ f < 1 9 + 10 (f)
1 ≤ f < 10 19,0
10 ≤ f < 40 24 − 5 lg(f)
T1-C 40 ≤ f < 130 16,0
130 ≤ f < 400 37 − 10 lg(f)
400 ≤ f < 600 11,0
600 ≤ f ≤ 1 250 38,8 − 10 lg(f)
Table 147 – Informative return loss values for a single pair channel at key frequencies
Frequency Minimum return loss
MHz dB
Class
T1-A T1-B T1-C
0,1 9,8 10,0 10,0
1 13,0 19,0 19,0
20 13,0 17,5 17,5
100 – 16,0 16,0
250 – 13,0 13,0
500 – 11,0 11,0
600 – 11,0 11,0
1 000 – – 8,8
1 250 – – 7,8
6.6.3.2 Insertion loss
The insertion loss requirements are applicable to all single pair cabling Classes.
The insertion loss (IL) of a single pair channel shall meet the requirements in Table 148. The
insertion loss values for a single pair channel at key frequencies are given in Table 149 for
information only.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 148 – Insertion loss for a single pair channel
a
Class Frequency
Maximum insertion loss
MHz dB
0,2
b
T1-A-1000 0,1 ≤ f ≤ 20 10× 1,23 ff+ 0,01×+ + 10× 0,02 f
f
0,25
c
4,05× 1,82 ff+ 0,0091× + +×5 0,02 f
T1-A-400 0,1 ≤ f ≤ 20
f
0,25
c
0,1 ≤ f ≤ 20 1,05× 1,82 ff+ 0,0091× + + 4× 0,02 f
T1-A-100
f
0,25
c
0,1 ≤ f ≤ 600 1,05× 1,8 ff+ 0,005× + + 4× 0,02 f
T1-B
f
0,25
c
1,05× 1,8 ff+ 0,005× + + 4× 0,02 f
T1-C 0,1 ≤ f ≤ 1 250
f
a
Insertion loss (IL) at frequencies that correspond to calculated values of less than 3,0 dB shall revert to a
requirement of 3,0 dB.
b
Cord cable used in the channel is expected to have no de-rating based on construction.
c
10 m of 50 % de-rated (based on construction) cord cable is assumed in the equation.
Table 149 – Informative insertion loss values for a single pair channel
at key frequencies
Frequency Maximum insertion loss
MHz dB
Class
T1-A-1000 T1-A-400 T1-A-100 T1-B T1-C
0,1 10,3 5,6 3,0 3,0 3,0
1 14,6 8.5 3,0 3,0 3,0
20 58,3 34,4 9,2 9,0 9,0
100 – – – 20,3 20,3
250 – – – 32,5 32,5
500 – – – 46,7 46,7
600 – – – 51,4 51,4
1 000 – – – – 67,6
1 250 – – – – 76,2
6.6.3.3 Direct current (DC) loop resistance
The DC loop resistance requirements are applicable to all single pair cabling Classes.
The DC loop resistance of a single pair channel shall meet the requirements in Table 150.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 150 – Direct current (DC) loop resistance for a single pair channel at 20 °C
a
DC loop resistance
d
Class
Maximum DC loop resistance at 20 °C
Ω
b
47,0
T1-A-1000
c
58,5
T1-A-400
c
14,9
T1-A-100
c
T1-B 14,9
c
T1-C 14,9
a
This requirement is based on channels designed for the MICE C1 environmental classification.
b
The maximum DC loop resistance at 20 °C of the cable pair (excluding connections) within a link, used in a
channel shall be 0,046 Ω/m. This shall be achieved by an appropriate design.
c
The maximum DC loop resistance at 20 °C of the cable pair (excluding connections) within a link, used in a
channel shall be 0,145 Ω/m. This shall be achieved by an appropriate design.
d
To correct DC loop resistance to a different temperature, the conversion is as follows:
R R [1+ α(T− T )]
ref ref
where
R is conductor resistance at temperature T in Ω;
is conductor resistance at reference temperature T , usually 20 °C, in Ω;
R
ref ref
α is temperature coefficient of resistance for the conductor material (copper = 0,003 93) per °C;
T is conductor temperature in °C;
T is reference temperature that α is specified at for the conductor material in °C.
ref
6.6.3.4 Direct current (DC) resistance unbalance
The DC resistance unbalance requirements are applicable to all single pair cabling Classes.
The DC resistance unbalance between the two conductors of a single pair channel shall not
exceed 3 % or 200 mΩ, whichever is greater.
6.6.3.5 DC current carrying capacity
ISO/IEC TS 29125 shall be used to assess the DC current carrying capacity. ISO/IEC 14763-2
shall be used to apply proper planning and installation. Each conductor of a single pair cabling
channel is intended to support DC current carrying capacity of up to 2,0 A, dependent on
installation conditions. Single pair channels shall be administrated and labelled according to
ISO/IEC 14763-2.
Multi-pair cabling using Category 5 through Category 8.2 cabling components support 0,75 A.
When using these components within a single pair channel, the resulting channel is limited to
0,75 A, see ISO/IEC TR 11801-9911.
NOTE Table G.2 provides guidance regarding the maximum channel length in relation to remote powering.
=
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
6.6.3.6 Dielectric withstand
The minimum dielectric withstand requirements are applicable to all single pair cabling Classes.
Dielectric withstand of single pair channels shall be a minimum of 1 000 V DC conductor-to-
conductor and shall be a minimum of 1 000 V DC conductor-to-screen or conductor to earth, if
a screen is not present, in accordance with IEC 61196-1-105.
6.6.3.7 Propagation delay
The maximum propagation delay requirements are applicable to all single pair cabling Classes.
The propagation delay of a single pair channel shall meet the requirements in Table 151.
Propagation delay values for a single pair channel at key frequencies are given in Table 152
for information only.
Table 151 – Propagation delay for a single pair channel
Maximum propagation delay
Frequency
Class
µs
MHz
0,360
5, 340+ +×10 0, 002 5
0,1 ≤ f ≤ 20
T1-A-1000
f
0,144
2, 136+ +×5 0, 002 5
0,1 ≤ f ≤ 20
T1-A-400
f
0,036
0, 534+ + 4× 0, 002 5
0,1 ≤ f ≤ 20
T1-A-100
f
0,036
0, 534+ + 4× 0, 002 5
0,1 ≤ f ≤ 600
T1-B
f
0,036
0, 534+ + 4× 0, 002 5
0,1 ≤ f ≤ 1 250
T1-C
f
Table 152 – Informative propagation delay values for
a single pair channel at key frequencies
Frequency Maximum propagation delay
MHz µs
Class
T1-A-1000 T1-A-400 T1-A-100 T1-B T1-C
0,1 6,503 2,604 0,658 0,658 0,658
1 5,725 2,293 0,580 0,580 0,580
20 5,445 2,181 0,552 0,552 0,552
100 – – – 0,548 0,548
250 – – – 0,546 0,546
500 – – – 0,546 0,546
600 – – – 0,545 0,545
1 000 – – – – 0,545
1 250 – – – – 0,545
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
6.6.3.8 Unbalance attenuation and coupling attenuation
6.6.3.8.1 General
Unbalance attenuation (TCL and ELTCTL) is specified for unscreened systems. Coupling
attenuation is specified for screened systems.
6.6.3.8.2 Unbalance attenuation, near-end
The unbalance attenuation near-end is measured as transverse conversion loss (TCL).
Minimum TCL requirements are applicable to unscreened systems. The TCL of a single pair
channel that is intended to be subjected to an environmental classification E shall meet the
x
requirements in Table 153. TCL values for a single pair unscreened channel at key frequencies
are given in Table 154 for information only.
The TCL requirements shall be met at both ends of the cabling.
Table 153 – TCL for a single pair channel for unscreened systems
Class Frequency Environmental classification
b b
MHz E
E E
2 3
a
Minimum TCL
dB
f f f
T1-A 0,1 ≤ f ≤ 20
50− 20lg 50− 20lg 60− 20lg
10 10 10
f f f
T1-B 0,1 ≤ f ≤ 600
50− 20lg 60− 20lg 70− 20lg
10 10 10
f f f
T1-C 0,1 ≤ f ≤ 1 250
50− 20lg 60− 20lg 70− 20lg
10 10 10
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
a
Calculated values of greater than 50 dB shall revert to a requirement of 50 dB.
b
Reference implementation does not ensure channel compliance for E or E .
2 3
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 154 – Informative TCL values for a single pair
unscreened channel at key frequencies
Frequency Minimum TCL
MHz dB
Class
T1-A T1-B T1-C
E E E E E E E E E
1 2 3 1 2 3 1 2 3
0,1 50,0 50,0 50,0 50,0 50,0 50,0 50,0 50,0 50,0
1 50,0 50,0 50,0 50,0 50,0 50,0 50,0 50,0 50,0
20 44,0 44,0 50,0 44,0 50,0 50,0 44,0 50,0 50,0
100 – – – 30,0 40,0 50,0 30,0 40,0 50,0
250 – – – 22,0 32,0 42,0 22,0 32,0 42,0
500 – – – 16,0 26,0 36,0 16,0 26,0 36,0
600 – – – 14,4 24,4 34,4 14,4 24,4 34,4
1 000 – – – – – – 10,0 20,0 30,0
1 250 – – – – – – 8,1 18,1 28,1
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
6.6.3.8.3 Unbalance attenuation, far-end
The unbalance attenuation far-end is measured as equal level transverse conversion transfer
loss (ELTCTL).
Minimum ELTCTL requirements are applicable to unscreened systems. The ELTCTL of a single
pair channel that is intended to be subjected to an environmental classification E shall meet
x
the requirements in Table 155. ELTCTL values for a single pair unscreened channel at key
frequencies are given in Table 156 for information only.
The ELTCTL requirements shall be met at both ends of the cabling.
Table 155 – ELTCTL for a single pair channel for unscreened systems
Class Frequency Environmental classification
MHz E E E
1 2 3
a, b, c
Minimum ELTCTL
dB
T1-A-1000 0,1 ≤ f ≤ 20 20− 20lg( f) 28− 20lg( f) 36− 20lg( f)
T1-A-400 0,1 ≤ f ≤ 20 24− 20lg( f) 32− 20lg( f) 40− 20lg( f)
34− 20lg( f) 50− 20lg( f)
T1-A-100 0,1 ≤ f ≤ 20 42− 20lg f
( )
34− 20lg f 50− 20lg f
( ) 42− 20lg f ( )
T1-B 0,1 ≤ f ≤ 600 ( )
42− 20lg( f) 50− 20lg( f)
T1-C 0,1 ≤ f ≤ 1 250 34− 20lg( f)
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
a
ELTCTL at frequencies that correspond to measured TCTL values of greater than 80,0 dB shall be for
information only.
b
Calculated values of greater than 50 dB shall revert to a requirement of 50 dB.
c
Calculated values of less than 3 dB shall revert to a requirement of 3 dB.
Table 156 – Informative ELTCTL values for a single pair
unscreened channel at key frequencies
Frequency Minimum ELTCTL
MHz dB
Class
a
T1-A-1000 T1-A-400
T1-A-100, T1-B, T1-C
E E E E E E E E E
1 2 3 1 2 3 1 2 3
0,1 40,0 48,0 56,0 44,0 50,0 50,0 50,0 50,0 50,0
1 20,0 28,0 36,0 24,0 32,0 40,0 34,0 42,0 50,0
20 3,0 3,0 10,0 3,0 6,0 14,0 8,0 16,0 24,0
100 – – – – – – 3,0 3,0 10,0
250 – – – – – – 3,0 3,0 3,0
500 – – – – – – 3,0 3,0 3,0
600 – – – – – – 3,0 3,0 3,0
1 000 – – – – – – 3,0 3,0 3,0
1 250 – – – – – – 3,0 3,0 3,0
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
a
The informative values are only applicable to the highest frequency of the referenced Class.
6.6.3.8.4 Coupling attenuation
Minimum coupling attenuation requirements are applicable to screened systems.
The coupling attenuation of a single pair channel that is intended to be subjected to an
environmental classification E shall meet the requirements in Table 157. Coupling attenuation
x
values for a single pair screened channel at key frequencies are given in Table 158 for
information only.
The coupling attenuation requirements shall be met at both ends of the cabling and shall be
achieved by design and installation in accordance with manufacturer's instructions.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 157 – Coupling attenuation for a single pair channel for screened systems
Class Frequency Environmental classification
MHz E E E
1 2 3
Minimum coupling attenuation
dB
T1-A 0,1 ≤ f ≤ 20
54 64 74
0,1 ≤ f < 20 54 64 74
T1-B
80− 20lg f 90− 20lg f 100− 20lg f
20 ≤ f ≤ 600 ( ) ( ) ( )
0,1 ≤ f < 20 54 64 74
T1-C
20 ≤ f ≤ 1 250 80− 20lg( f) 90− 20lg( f) 100− 20lg( f)
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
Table 158 – Informative coupling attenuation values
for a single pair screened channel at key frequencies
Frequency Minimum coupling attenuation
MHz dB
Class
T1-A T1-B T1-C
E E E E E E E E E
1 2 3 1 2 3 1 2 3
0,1 54,0 64,0 74,0 54,0 64,0 74,0 54,0 64,0 74,0
1 54,0 64,0 74,0 54,0 64,0 74,0 54,0 64,0 74,0
20 54,0 64,0 74,0 54,0 64,0 74,0 54,0 64,0 74,0
100 – – – 40,0 50,0 60,0 40,0 50,0 60,0
250 – – – 32,0 42,0 52,0 32,0 42,0 52,0
500 – – – 26,0 36,0 46,0 26,0 36,0 46,0
600 – – – 24,4 34,4 44,4 24,4 34,4 44,4
1 000 – – – – – – 20,0 30,0 40,0
1 250 – – – – – – 18,1 28,1 38,1
NOTE E , E and E relate to the MICE environmental classification.
1 2 3
6.6.3.9 Alien crosstalk
6.6.3.9.1 General
The following alien crosstalk requirements are applicable to all single pair cabling Classes. For
screened channels, additional guidance is provided in 6.6.3.9.4.
6.6.3.9.2 Power sum alien NEXT (PS ANEXT)
The PS ANEXT of a single pair channel shall meet the requirements in Table 159. PS ANEXT
values for a single pair channel at key frequencies are given in Table 160 for information only.
The PS ANEXT requirements shall be met at both ends of the channel.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
PS ANEXT is computed as follows:
−ANEXT
l
N
PS ANEXT =−10 lg 10
∑ (25)
l= 1
where
l is the number of the disturbing channel,
N is the number of disturbing channels,
ANEXT is the alien near-end crosstalk loss coupled from disturbing channel (l) to the
l,
disturbed channel.
Table 159 – PS ANEXT for a single pair channel
a
Class Frequency Minimum PS ANEXT
MHz dB
f
T1-A 0,1 ≤ f ≤ 20
37,5− 17lg
20
f
0,1 ≤ f < 100 60− 10lg
100
T1-B
f
100 ≤ f ≤ 600 60− 15lg
100
f
0,1 ≤ f < 100 65− 10lg
100
T1-C 100 ≤ f < 600 65
f
600 ≤ f ≤ 1 250 65− 15lg
a
PS ANEXT at frequencies that correspond to calculated values of greater than 67,0 dB shall revert to a
requirement of 67,0 dB.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 160 – Informative PS ANEXT values for a single pair channel at key frequencies
Frequency Minimum PS ANEXT
MHz dB
Class
T1-A T1-B T1-C
0,1 67,0 67,0 67,0
1 59,6 67,0 67,0
20 37,5 67,0 67,0
100 – 60,0 65,0
250 – 54,0 65,0
500 – 49,5 65,0
600 – 48,3 65,0
1 000 – – 61,7
1 250 – – 60,2
6.6.3.9.3 Power sum alien ACR-F (PS AACR-F)
The PS AACR-F of a single pair channel shall meet the requirements in Table 161.
The PS AACR-F of each pair of a channel, at maximum implementation, at key frequencies is
given in Table 162 for information only.
The PS AACR-F shall be met at both ends of the channel.
The PS AACR-F is determined according to Equation (26).
PS AACR-F PS AFEXT− IL
(26)
where
IL is the measured insertion loss of the disturbed channel,
PS AFEXT is the power sum alien far-end crosstalk loss coupled to the disturbed channel.
=
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 161 – PS AACR-F for a single pair channel
a, b
Class Frequency
Minimum PS AACR-F
MHz dB
c
53,0 – 20 lg (f)
T1-A-1000 0,1 ≤ f ≤ 20
d
0,1 ≤ f ≤ 20 57,0 – 20 lg (f)
T1-A-400
e
0,1 ≤ f ≤ 20 62,0 – 20 lg (f)
T1-A-100
e
77,0 – 20 lg (f)
0,1 ≤ f ≤ 600
T1-B
e
T1-C 0,1 ≤ f ≤ 1 250 98,0 – 20 lg (f)
a
PS AACR-F at frequencies that correspond to calculated PS AFEXT values of greater than 80,0 dB shall be
for information only.
b
PS AACR-F at frequencies that correspond to calculated values of greater than 75,0 dB shall revert to a
requirement of 75,0 dB.
c
The reference length is 1 000 m.
d
The reference length is 400 m.
e
The reference length is 100 m.
Table 162 – Informative PS AACR-F values for a single pair channel at key frequencies
Frequency Minimum PS AACR-F
MHz dB
Class
T1-A-1000 T1-A-400 T1-A-100 T1-B T1-C
a
75,0 75,0 75,0
0,1 73,0 75,0
a
53,0 57,0 62,0 75,0
1 75,0
20 27,0 31,0 36,0 51,0 72,0
100 – – – 37,0 58,0
250 – – – 29,0 50,0
500 – – – 23,0 44,0
600 – – – 21,4 42,4
1 000 – – – – 38,0
1 250 – – – – 36,1
a
PS AACR-F values at and below 1 MHz are affected by the computed insertion loss.
6.6.3.9.4 Alien crosstalk and coupling attenuation for single pair screened channels
When coupling attenuation for a channel meets or exceeds the values of Table 163, the
PS ANEXT and PSAACR-F limits are met by design.
The coupling attenuation of a single pair channel to meet PS ANEXT and PS AACR-F limits at
key frequencies is given in Table 164 for information only.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 163 – Alien crosstalk and coupling attenuation for single pair screened channels
Class Frequency Minimum coupling attenuation to meet PS ANEXT and PS AACR-F limits
MHz dB
T1-A 0,1 ≤ f ≤ 20 60,0
0,1 ≤ f < 20 64,0
T1-B
20 ≤ f ≤ 600 90− 20lg( f)
0,1 ≤ f < 20 79,0
T1-C
20 ≤ f ≤ 1 250 105− 20lg( f)
Table 164 – Informative coupling attenuation to meet alien crosstalk values
for a single pair screened channel at key frequencies
Frequency Minimum coupling attenuation to meet PS ANEXT and PS AACR-F limits
MHz dB
Class
T1-A T1-B T1-C
0,1 60,0 64,0 79,0
1 60,0 64,0 79,0
20 60,0 64,0 79,0
100 – 50,0 65,0
250 – 42,0 57,0
500 – 36,0 51,0
600 – 34,4 49,4
1 000 – – 45,0
1 250 – – 43,1
6.6.4 Cable sharing
When more than one single pair outlet is served by a single cable, each pair (channel) within
the shared sheath shall comply with all of the single pair channel specifications specified in 6.6.
The combined alien crosstalk from internal and external disturbers into the victim channel within
the shared sheath shall comply with the PS ANEXT and PS AACR-F specifications in 6.6.3.9.
See Annex H for additional information on cable sharing.
Classes C through F , Class I and II, shall be evaluated for compliance to all requirements of
A
6.6 before being used for cable sharing, see ISO/IEC TR 11801-9911.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
7 Link performance requirements
7.1 General
Replace the existing Figure 7 with the following new figure:
a
The limits for the 2-connection PL are those of a 2-connection link.
b
The limits for the CP link are those of a 2-connection link.
c
The limits for the 3-connection PL are those of a 3-connection link.
Figure 7 – Link designations
7.2 Balanced cabling
7.2.7 Direct current loop resistance
Replace the existing text and tables with the following new text and tables:
The DC loop resistance of each pair of a 2-connection or 3-connection link shall meet the
requirements derived by the equation in Table 60.
The DC loop resistance of each pair of a link, with maximum implementation, at key frequencies
is given in Table 61 for information only.
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 60 – DC loop resistance for a 2-connection or 3-connection link
a
DC loop resistance
b b
Class
Maximum DC loop resistance at 60 °C Informative DC loop resistance at 20 °C
Ω Ω
A 530 446,7
B 140 118
C 34 28,7
D (L/100) × 22 + n × 0,4 (L/100) × 18,86 + n × 0,4
E (L/100) × 22 + n × 0,4 (L/100) × 18,86 + n × 0,4
E (L/100) × 22 + n × 0,4 (L/100) × 18,86 + n × 0,4
A
F (L/100) × 22 + n × 0,4 (L/100) × 18,86 + n × 0,4
F (L/100) × 22 + n × 0,4 (L/100) × 18,86 + n × 0,4
A
BCT-B (L/100) × 22 + 2 × 0,4 (L/100) × 18,86 + 2 × 0,4
I (L/100) × 16,0 + 2 × 0,4 (L/100) × 14,0 + 2 × 0,4
II (L/100) × 16,0 + 2 × 0,4 (L/100) × 14,0 + 2 × 0,4
L = L + L × Y
FC CP
where
L is the length of fixed cable (m);
FC
L is the length of consolidation point cord, where present (m);
CP
Y is the the ratio of consolidation point cord cable insertion loss (dB/m) to fixed cable insertion loss (dB/m)
(see 9.3.2.6);
n = 2 for 2-connection link configurations (see Figure 6).
n = 3 for 3-connection link configurations (see Figure 6).
a
This requirement is based on links designed for the MICE C1 environmental classification.
b
To correct DC loop resistance to a different temperature, the conversion is as follows:
R R [1+ α(T− T )]
ref ref
where
R is the conductor resistance at temperature T in Ω;
R is the conductor resistance at reference temperature T , usually 20 °C, in Ω;
ref ref
α is the temperature coefficient of resistance for the conductor material (copper = 0,003 93) per °C;
T is the conductor temperature in °C;
T is the reference temperature in °C that α is specified at for the conductor material.
ref
Table 61 – Informative DC loop resistance for links with
maximum implementation
Maximum DC loop resistance
Ω
Reference
temperature
Class
A B C D E E F F BCT-B-L BCT-B-M I II
A A
60 °C 530 140 34 21,0 21,0 21,0 21,0 21,0 2,5 5,4 5,0 5,0
20 °C 446,7 118 28,7 18,2 18,2 18,2 18,2 18,2 2,3 4,8 4,4 4,4
=
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
7.2.9 Propagation delay
Replace the existing text of the second paragraph with the following new text:
A method of establishing whether link propagation delay performance is sufficient to support
the channel requirements of Table 18 is to demonstrate that the margin between the measured
value and the channel limits of Table 18 is adequate to accommodate any additional cabling
components used to create a channel. This method requires a performance characterization of
the additional components to guarantee the channel performance can be met.
7.2.10 Delay skew
Replace the existing text of the second paragraph with the following new text:
A method of establishing whether link delay skew performance is sufficient to support the
channel requirements of Table 20 is to demonstrate that the margin between the measured
value and the channel limits of Table 20 is adequate to accommodate any additional cabling
components used to create a channel. This method requires a performance characterization of
the additional components to guarantee the channel performance can be met.
7.2.11 Unbalance attenuation and coupling attenuation
7.2.11.4 Coupling attenuation
Replace the existing text of the first paragraph with the following new text:
Minimum coupling attenuation requirements are only applicable to permanent link Classes D
through F , BCT-B, I and II. The coupling attenuation of a permanent link that is intended to be
A
subjected to an environmental classification E shall meet the requirements in Table 70.
x
Replace the existing Tables 70 and 71 with the following new tables:
Table 70 – Coupling attenuation for a screened permanent link
Class Frequency Environmental classification
MHz E E E
1 2 3
a
Minimum coupling attenuation
dB
30≤≤f 100 40 50 60
D, E, E , F, F
A A
a
80− 20lg ( f ) 90− 20lg ( f ) 100− 20lg ( f )
100 ≤ f ≤ f
u
30≤
85 85 85
300≤
BCT-B 80 80 80
75 75 75
470≤≤f 1000
30≤≤f 100 50 50 60
I, II
100≤≤f 2 000 90− 20lg ( f ) 90− 20lg ( f ) 100− 20lg ( f )
a
f is the upper frequency of the Class.
u
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Table 71 – Informative coupling attenuation values for
a screened permanent link at key frequencies
Frequency Minimum coupling attenuation
MHz dB
Class
a
BCT-B I, II
D, E, E , F, F
A A
E E E E E E E E E
1 2 3 1 2 3 1 2 3
30 40,0 50,0 60,0 85,0 85,0 85,0 50,0 50,0 60,0
100 40,0 50,0 60,0 85,0 85,0 85,0 50,0 50,0 60,0
250 32,0 42,0 52,0 85,0 85,0 85,0 42,0 42,0 52,0
500 26,0 36,0 46,0 75,0 75,0 75,0 36,0 36,0 46,0
1 000 20,0 30,0 40,0 75,0 75,0 75,0 30,0 30,0 40,0
1 600 – – – – – – 25,9 25,9 35,9
2 000 – – – – – – 24,0 24,0 34,0
a
The informative values are applicable to the upper frequency of the Class.
7.2.12.6 Alien crosstalk and coupling attenuation for screened links
Replace the existing Table 80 with the following revised table.
Table 80 – Alien crosstalk and coupling attenuation for screened links
Minimum coupling attenuation to Minimum coupling attenuation to
Class Frequency
meet PS ANEXT limits meet PS AACR-F limits
MHz dB dB
30≤≤f 100
50 50
E
A
100≤≤f 500 90− 20lg ( f ) 90− 20lg ( f )
30≤≤f 100
50 50
F
100≤≤f 600 90− 20lg ( f ) 90− 20lg ( f )
30≤≤f 100
65 65
F
A
100≤≤f 1 000 105− 20lg ( f ) 105− 20lg ( f )
30≤≤f 100
65 65
I
100≤≤f 2 000 105− 20lg ( f ) 105− 20lg ( f )
30≤≤f 100 65 65
II
100≤≤f 2 000 105− 20lg ( f ) 105− 20lg ( f )
7.4 Optical fibre cabling
Replace, in the last paragraph, "Table 93", with "Table 92".
ISO/IEC 11801-1:2017/AMD1:2025 © ISO/IEC 2025
Insert new subclause:
7.5 Single pair balanced cabling
7.5.1 General
Clause 7.5 contains requirements for single pair balanced links of Classes T1-A, T1-B and
T1-C.
The parameters specified in 7.5 apply to single pair balanced links with screened or unscreened
cable elements, with or without an overall screen, unless explicitly stated otherwise. When
requir
...
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