ISO/IEC 11801:1995/AMD2:1999

INTERNATIONAL
ISO/IEC
STANDARD
AMENDMENT 2
1999-12
Amendment 2
Information technology –
Generic cabling for customer premises
Amendement 2
Technologies de l'information –
Câblage générique des locaux d'utilisateurs

 ISO/IEC 1999
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– 2 – 11801 Amend. 2 © ISO/IEC:1999(E)

FOREWORD
Amendment 2 to International Standard ISO/IEC 11801 was prepared by subcommittee 25:

Interconnection of information technology, of ISO/IEC joint technical committee 1: Information

technology.
Attention is drawn to the possibility that some of the elements in this amendment may be the

subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all

such patent rights.
__________
General
Update references to tables, the numbers of which have been changed.
Page 2
Insert, in the existing list, the titles of the following standards:
IEC 60793-1 (all parts), Optical fibres – Part 1: Generic specification
IEC 60874-19 (all parts), Connectors for optical fibres and cables
IEC 61035-1, Specification for conduit fittings for electrical installations – Part 1: General
requirements
IEC 61280-4 (all parts), Fibre optic communication subsystem basic test procedures – Part 4:
Fibre optic requirements
IEC 61935-1,— Generic specification for the testing of generic cabling in accordance with
1)
ISO/IEC 11801 – Part 1: Test methods
Page 5
3.1 Definitions
Add a new definition and renumber the following ones:
3.1.34
permanent link
the transmission path between two mated interfaces of generic cabling, excluding equipment
cables, work area cables and cross-connections
________
1)
To be published.
11801 Amend. 2 © ISO/IEC:1999(E) – 3 –

Page 8
4 Conformance
Add the following new paragraph:

References to the requirements and classifications specified in this International Standard

shall specifically differentiate components and systems conforming to ISO/IEC 11801 (1995) from

those that are qualified according to ISO/IEC 11801 (1995), including amendment 1 (1999)

and amendment 2 (1999), by specifically referencing ISO/IEC 11801 (1995), including amend-

ment 1 (1999) and amendment 2 (1999). For the purpose of component marking and system

identification, it is appropriate to directly reference the year of publication of the second
amendment, or to use a specific designation that provides linkage to it.
Page 18
6.1.1 Horizontal distances
Replace the entire subclause by the following new subclause:
The maximum horizontal cable length shall be 90 m independent of medium (see figure 6).
This is the cable length from the mechanical termination of the cable in the floor distributor to
the telecommunications outlet in the work area.
In establishing the maximum length of the horizontal channel, the optional use of a
crossconnect or an interconnect places different requirements on the total length of the
flexible cables used. Figure 7 shows examples of horizontal channel implementations which
reflect these differing requirements of maximum cable length.
Channel
Permanent link
EQP C C C C C TE
TP TO
FD
90 m max.
EB A
A + B + E = 9 m maximum
Figure 7a – Balanced copper horizontal cabling (with crossconnect)

Channel
Permanent link
EQP C C C C TE
TP TO
FD
90 m max.
EA
A + E = 10 m maximum
Figure 7b – Balanced copper horizontal cabling (with interconnect)

– 4 – 11801 Amend. 2 © ISO/IEC:1999(E)

Channel
Permanent link
EQP C C s s C C TE
TO
FD
90 m max.
EA
A + E = 10 m maximum
Figure 7c – Optical fibre cabling (with interconnect)
Key
C connection (e.g. plug and jack or mated optical connection)
S optical fibre splice
EQP application specific equipment
NOTE 1 All lengths are mechanical lengths.
NOTE 2 See annex C for further information on flexible cables.
Figure 7 – Examples of horizontal channel implementation
In figure 7a, the maximum total length of work area cable, equipment cable and patch cord
is 9 m based upon flexible cables with 50 % greater attenuation than the horizontal cable and
includes a crossconnect in the floor distributor. In figure 7b, the maximum total length of work
area cable and equipment cable is 10 m also based upon flexible cables with 50 % greater
attenuation than the horizontal cable and includes an interconnect in the floor distributor. In
both cases the transition point is optional. It is required that the performance of the horizontal
cabling is not degraded by the inclusion of the transition point.
For optical fibre, the implementation is shown in figure 7c. An optical fibre splice, in
accordance with clause 9, is allowed at both ends of the horizontal cable.
See clause 9 and annex C for requirements for patch cords and other flexible cables. In all
cases, equipment cables that meet or have better performance characteristics than patch cord
requirements are recommended.
Page 23
7 Link specifications
Replace the existing title and text of this clause by the following new text:
7 Permanent link and channel specifications
7.1 Permanent links and channels
7.1.1 General
This clause defines the permanent link and channel performance requirements of installed
generic cabling. The performance of the cabling is specified for individual permanent links and
channels and for two different media types (balanced cables and optical fibre). A tutorial on
the material in this clause is provided in annex F.

11801 Amend. 2 © ISO/IEC:1999(E) – 5 –

The design rules of clause 6 can be used to create generic cabling links and channels
containing components specified in clauses 8 and 9. It is not necessary to measure every

parameter specified in this clause as conformance may also be proven by suitable design.

The permanent link and channel specifications in this clause allow for the transmission of

defined classes of applications over distances other than those of clause 6, and/or using

media and components with different transmission performances than those of clauses 8

and 9.
The permanent link and channel performance requirements specified in this clause shall be

met at each interface specified for each medium.

The performance requirements described in this clause may be used as verification tests for
any implementation of this International Standard, using the test methods defined, or referred
to, by this clause. The permanent link requirements are primarily intended to provide a basis
for the acceptance testing of installed cabling. The channel requirements are primarily for
application developers but are able to be used for troubleshooting where application support
is under development.
Permanent link and channel performance specifications shall be met for all temperatures at
which the cabling is intended to operate. Performance testing may be carried out at ambient
temperature, but there shall be adequate margins to account for temperature dependence of
cabling components as per their specifications. The effects of ageing should also be taken
into account. In particular, consideration should be given to measuring performance at worst
case temperatures, or calculating worst case performance based on measurements made at
other temperatures.
Care should be exercised in the interpretation of any results obtained from alternative test
methods or practices. When needed, correlation factors should be identified and applied.
7.1.2 Permanent links
The performance of a permanent link is specified at and between interfaces to the link. The
permanent link comprises only passive sections of cable and connecting hardware. A
transition point may also be included in the horizontal subsystem. Active and passive
application specific hardware is not addressed by this International Standard (figure 11).
FD
TP
TO
Permanent link
Figure 11 – Permanent link
Figure 12a shows an example of terminal equipment in the work area connected to a host
using three links; two optical fibre links and a balanced cable link. The optical fibre and
balanced cable links are connected together using an optical fibre to balanced cable
converter, a cross-connect and two equipment cables. Interfaces to the cabling are at each
end of a permanent link. Interfaces to the cabling are specified at the TO and at any point
where application specific equipment is connected to the cabling; the work area and
equipment cables are not included in the permanent link.

– 6 – 11801 Amend. 2 © ISO/IEC:1999(E)

Interfaces to the cabling are at each end of a permanent link. Interfaces to the cabling are
specified at the TO and at any point where application specific equipment is connected to the

cabling; the work area and equipment cables are not included in the permanent link.

NOTE For balanced cabling the limits for the permanent link in this clause are calculated on the basis of 90 m of

installed cable and two connections.

7.1.3 Channels
The performance of the channel is specified at and between interfaces to the channel. The
cabling comprises only passive sections of cable, connecting hardware, work area cords,

equipment cords and patch cords.

Figure 12b shows an example of terminal equipment in the work area connected to a host
using two channels; an optical fibre channel and a balanced cabling channel. The optical fibre
and balanced cabling channels are connected together using an optical fibre to balanced
cable converter. There are four channel interfaces; one at each end of the copper channel,
and one at each end of the optical fibre channel. Equipment connections are not considered
to be part of the channel. All work area, equipment cables and patch cords are included in the
channel.
Terminal
CD BD
FD
equipment
TP TO
Balanced cable
Optical fibre
Optical fibre
permanent link
permanent
permanent
link link
Host
Opto-electronic
converter (optional)
Figure 12a – Location of cabling interfaces and extent of associated permanent links
Terminal
CD BD
FD
equipment
TO
TP
Balanced cable channel
Optical fibre
channel
Host
Opto-electronic
converter (optional)
Figure 12b – Location of cabling interfaces and extent of associated channels

11801 Amend. 2 © ISO/IEC:1999(E) – 7 –

FD
TP
TO
C
A
Horizontal cable
B
(90 m)
A + B + C = 9 m
NOTE For balanced cabling, this example assumes the use of flexible cables with 50 % greater attenuation
(dB/m) than the horizontal cable, and a cross-connection in the floor distributor, thus 3 connections. In this case,
the maximum length of work area, equipment, and patch cable is 9 m. A longer channel length may be achieved by
using flexible cables with better attenuation performance.
Figure 12c – Class D channel implementation (with cross-connection)
FD
TP
TO
5 m
5 m
Horizontal cable
(90 m)
NOTE For balanced cabling, this example assumes the use of flexible cables with 50 % greater attenuation (dB/m) than
the horizontal cable. In this case, the maximum length of work area and equipment cables is 10 m. This example
results in a calculated channel attenuation of 23,9 dB at 100 MHz using category 5 component requirements.
Figure 12d – Class D channel implementation (with interconnection)
Key
Interface to the generic cabling
Optional interface when using a crossconnection
Figure 12 – Examples of cabling systems
7.2 Classification of applications, links and channels
7.2.1 Application classification

Five application classes for cabling have been identified for the purposes of this International
Standard. This ensures that the limiting requirements of one system do not unduly restrict
other systems.
The application classes are:
Class A includes speech band and low-frequency applications. Copper cabling permanent
links and channels supporting* Class A applications are referred to as Class A
permanent links and Class A channels respectively.
Class B includes medium bit rate data applications. Copper cabling permanent links
and channels supporting* Class B applications are referred to as Class B
permanent links and Class B channels respectively.

– 8 – 11801 Amend. 2 © ISO/IEC:1999(E)

Class C includes high bit rate data applications. Copper cabling permanent links and

channels supporting* Class C applications are referred to as Class C

permanent links and Class C channels respectively.

Class D includes very high bit rate data applications. Copper cabling permanent links

and channels supporting* Class D applications are referred to as Class D

permanent links and Class D channels respectively.

Optical Class includes high and very high bit rate data applications. Optical fibre permanent

links and channels supporting* Optical Class applications are referred to as

Optical Class permanent links and Optical Class channels respectively.

NOTE *Permanent link specifications are provided for field test verification. Channel values provide minimum
requirements for application support.
Annex G gives examples of applications that fall within the various classes.
7.2.2 Link and channel classification
Generic cabling, when configured to support particular applications, comprises one or more
permanent links and channels. Five permanent link and channel classes are defined, which
relate to the application classes as indicated in 7.2.1.
Permanent link/channel class A specified up to 100 kHz
Permanent link/channel class B specified up to 1 MHz
Permanent link/channel class C specified up to 16 MHz
Permanent link/channel class D specified up to 100 MHz
Optical permanent link/channel class specified to support applications specified at 10 MHz
and above.
For copper cabling, a class A to D permanent link or channel is specified so that channels will
provide the minimum transmission performance to support applications of the related
application class. Links and channels of a given class will support all applications of a lower
class. Permanent link/channel class A is regarded as the lowest class.
Optical parameters are specified for single-mode and multimode optical fibre permanent links
and channels.
Class C and D permanent links and channels correspond to full implementations of category 3
1)
and category 5 horizontal cabling subsystems respectively, as specified in 6.1.
Table 2 relates the permanent link and channel classes to the categories of clauses 8 and 9.
This table indicates the channel length over which the various applications may be supported.

The distances presented are based on NEXT loss (for copper cables), bandwidth (for optical
fibre cables), and attenuation limits for various classes. Other characteristics of applications,
for example propagation delay, may further limit these distances.
________
1)
The use of link in clause 6 allows for a wider range of configurations than a permanent link in this amendment.

11801 Amend. 2 © ISO/IEC:1999(E) – 9 –

Table 2 – Channel lengths achievable with different categories and types of cabling

Medium Channel length
Class A Class B Class C Class D Optical class

1)
Category 3 balanced cable (8.1) 2 km 200 m ––
100 m
2)
Category 4 balanced cable (8.1) 3 km 260 m ––
150 m
2) 1)
Category 5 balanced cable (8.1) 3 km 260 m –
160 m 100 m
2) 2)
150 Ω balanced cable (8.2) 3 km 400 m –
250 m 150 m
3)
Multimode optical fibre (8.4) N/A N/A N/A N/A
2 km
4)
Singlemode optical fibre (8.5) N/A N/A N/A N/A
3 km
1)
The 100 m distance includes a 90 m length permanent link and a maximum allowance of 10 m of flexible
cable for patch cords/jumpers, work area and equipment connections.
2)
For distances greater than 100 m of balanced cable in the horizontal cabling subsystem, the applicable
application standards should be consulted.
3)
The minimum bandwidth for a 2 km multimode optical link is specified in 7.4.2. Multimode applications may
be limited to distances shorter than 2 km. Consult application standards for limitations.
4)
3 km is a limit defined by the scope of the International Standard and not a medium limitation.
Consideration should be given, when specifying and designing cabling, to the possible future
connection of cabling subsystems to form longer links and channels. The performance of
these longer links and channels will be lower than that of any of the individual subsystem links
and channels from which they are constructed. Measurement of permanent links and channels
should be made initially, upon installation of each cabling subsystem. Testing of combined
subsystems should be performed as required by the application.
7.3 Balanced cabling permanent links and channels
7.3.1 General
The parameters specified in this subclause apply to permanent links and channels with shielded
or unshielded cable elements, with or without an overall shield, unless explicitly stated otherwise.
Unless stated otherwise, outline test configurations for all measurements on balanced cabling
are given in annex A. Specialised test instruments are required for high frequency field
measurements on balanced cabling. The maximum application frequencies are based on
required permanent link and channel characteristics, and are not indicated by the maximum
specified frequency for the cabling. In the following tables, the requirements for attenuation,
NEXT loss, Power Sum NEXT loss, ACR, Power Sum ACR, ELFEXT and Power Sum ELFEXT
are given for discrete frequencies only. Transmission requirements shall also be met for all
intermediate frequencies. Requirements at intermediate frequencies are derived by linear

interpolation between frequencies on a semi-logarithmic (NEXT loss, Power Sum NEXT loss,
ACR, Power Sum ACR, ELFEXT and Power Sum ELFEXT) or logarithmic (attenuation) scale.
7.3.2 Nominal impedance
The designed nominal impedance of a permanent link and channel shall be 100 Ω, 120 Ω, or
150 Ω. The nominal impedance of permanent links and channels should be achieved by
suitable design, and the appropriate choice of cables and connecting hardware.
The variation of the input impedance of a permanent link and channel is characterised by the
return loss. The characteristic impedance of cables used in a permanent link and channel
shall be in accordance with the requirements of clause 8.

– 10 – 11801 Amend. 2 © ISO/IEC:1999(E)

7.3.3 Return loss
The return loss of a permanent link and channel shall meet or exceed the values shown in

tables 3 and 4. The return loss shall be measured according to IEC 61935-1. The return loss

shall be measured from both ends to allow a correct evaluation of the permanent link or

channel. Terminations that are matched to the nominal impedance of the cable (specifically

100 Ω, 120 Ω, 150 Ω) shall be connected to the cabling elements under test at the remote end

of the permanent link or channel.

Table 3 – Minimum return loss for permanent link

Frequency Minimum return loss
dB
MHz
Class C Class D
1 ≤ f < 16 15 17
16 ≤ f < 20 N/A 17
20 ≤ f ≤ 100 N/A 17-7 log(f/20)
Table 4 – Minimum return loss for a channel
Frequency Minimum return loss
dB
MHz
Class C Class D
1 ≤ f < 16 15 17
16 ≤ f < 20 N/A 17
20 ≤ f ≤ 100 N/A 17-10 log(f/20)
7.3.4 Attenuation (insertion loss)
The attenuation of a permanent link and channel shall not exceed the values shown in
tables 5 and 6 respectively, and shall be consistent with the design values of cable length and
cabling materials used. The attenuation of the permanent link or channel shall be measured
according to IEC 61935-1, except that the measured attenuation shall not be scaled to a
standard length. Class D permanent links and channels should comprise cables, which closely
follow the square root of frequency attenuation characteristic above 1 MHz.
The values in tables 5 and 6 are based on the requirements of the applications listed in annex G.
Table 5 – Maximum attenuation values for a permanent link

Frequency Maximum attenuation
dB
MHz
Class A Class B Class C Class D
0,1 16,0 5,5 N/A N/A
1,0 N/A 5,8 3,1 2,1
4,0 N/A N/A 5,8 4,1
10,0 N/A N/A 9,6 6,1
16,0 N/A N/A 12,6 7,8
20,0 N/A N/A N/A 8,7
31,25 N/A N/A N/A 11,0
62,5 N/A N/A N/A 16,0
100,0 N/A N/A N/A 20,6
11801 Amend. 2 © ISO/IEC:1999(E) – 11 –

Table 6 – Maximum attenuation values for a channel

Frequency Maximum attenuation
dB
MHz
Class A Class B Class C Class D

0,1 16,0 5,5 N/A N/A
1,0 N/A 5,8 4,2 2,5
4,0 N/A N/A 7,3 4,5
10,0 N/A N/A 11,5 7,0
16,0 N/A N/A 14,9 9,2
20,0 N/A N/A N/A 10,3
31,25 N/A N/A N/A 12,8
62,5 N/A N/A N/A 18,5
100,0 N/A N/A N/A 24,0
7.3.5 NEXT loss
7.3.5.1 Pair-to-pair NEXT loss
The pair-to-pair NEXT loss of a permanent link and channel shall meet or exceed the
values shown in tables 7 and 8 respectively, and shall be consistent with the design values of
cable length and cabling materials used. The NEXT loss shall be measured according to
IEC 61935-1 except that the measured NEXT loss shall not be adjusted for length. The NEXT
loss shall be measured from both ends to allow a correct evaluation of the permanent link or
channel. See also A.1.1.
The values in tables 7 and 8 are based on the NEXT loss requirements of the applications
listed in annex G.
Table 7 – Minimum NEXT loss for a permanent link
Frequency Minimum NEXT loss
dB
MHz
Class A Class B Class C Class D
0,1 27,0 40,0 N/A N/A
1,0 N/A 25,0 40,1 61,2
4,0 N/A N/A 30,7 51,8
10,0 N/A N/A 24,3 45,5
16,0 N/A N/A 21,0 42,3
20,0 N/A N/A N/A 40,7
31,25 N/A N/A N/A 37,6
62,5 N/A N/A N/A 32,7
100,0 N/A N/A N/A 29,3
– 12 – 11801 Amend. 2 © ISO/IEC:1999(E)

Table 8 – Minimum NEXT loss for a channel

Frequency Minimum NEXT loss
dB
MHz
Class A Class B Class C Class D

0,1 27,0 40,0 N/A N/A
1,0 N/A 25,0 39,1 60,3
4,0 N/A N/A 29,3 50,6
10,0 N/A N/A 22,7 44,0
16,0 N/A N/A 19,3 40,6
20,0 N/A N/A N/A 39,0
31,25 N/A N/A N/A 35,7
62,5 N/A N/A N/A 30,6
100,0 N/A N/A N/A 27,1
Equipment connectors are not accounted for in table 8 and may contribute to additional
crosstalk degradation.
7.3.5.2 Power Sum NEXT loss (PSNEXT)
The PSNEXT parameter is applicable to class D only. The PSNEXT of a class D permanent
link and channel shall meet or exceed the values shown in tables 9 and 10 respectively.
PSNEXT is computed from pair-to-pair NEXT as follows:
−NEXT −NEXT −NEXT
pp,1 pp,2 pp,3
 
 
10 10 10
PSNEXT = −10 log 10 + 10 + 10
 
 
Table 9 – Minimum PSNEXT loss for a permanent link
Frequency Minimum PSNEXT loss
dB
MHz
Class D
1,0 58,2
4,0 48,8
10,0 42,5
16,0 39,3
20,0 37,7
31,25 34,6
62,5 29,7
100,0 26,3
11801 Amend. 2 © ISO/IEC:1999(E) – 13 –

Table 10 – Minimum PSNEXT loss for a channel

Frequency
Minimum PSNEXT loss
dB
MHz
Class D
1,0 57,3
4,0 47,6
10,0 41,0
16,0 37,6
20,0 36,0
31,25 32,7
62,5 27,6
100,0 24,1
Power Sum NEXT is met if measured pair-to-pair NEXT values for each pair combination are
at least 1,8 dB better than those specified in tables 7 and 8 for permanent links and channels
respectively.
7.3.6 Attenuation to crosstalk loss ratio
7.3.6.1 Pair-to-pair ACR
This is the difference between the NEXT loss and the attenuation of the cabling in dB. It is
related to, but distinct from, the signal to crosstalk ratio (SCR) which accommodates the
transmit and receive signal levels of an application. By applying the requirements of 7.3.3,
7.3.4 and 7.3.5, the transmission requirements of the applications listed in annex G will be
met. The ACR of cabling is calculated by:
ACR = a − a (dB)
N
where
ACR is the attenuation to crosstalk loss ratio;
a is the NEXT loss, measured between any two pairs of the cabling. The NEXT loss shall
N
be measured according to IEC 61935-1, except that the measured NEXT loss shall not
be adjusted for length;
a is the attenuation of the cabling when measured according to IEC 61935-1, except that
the measured attenuation shall not be scaled to a standard length.
Table 11 – Minimum ACR values for permanent link

Frequency Minimum ACR
dB
MHz
Class D
1,0 59,1
4,0 47,7
10,0 39,4
16,0 34,5
20,0 32,0
31,25 26,6
62,5 16,7
100,0  8,7
– 14 – 11801 Amend. 2 © ISO/IEC:1999(E)

Table 12 – Minimum ACR values for channels

Frequency Minimum ACR
dB
MHz
Class D
1,0 57,8
4,0 46,1
10,0 37,0
16,0 31,4
20,0 28,7
31,25 22,9
62,5 12,1
100,0  3,1
7.3.6.2 Power Sum ACR (PSACR)
The PSACR parameter is applicable to class D only. The PSACR of a class D permanent link
and channel shall meet or exceed the values shown in tables 13 and 14 respectively. The
Power Sum ACR is computed from Power Sum NEXT and attenuation as follows:
PSACR = PSNEXT – a
Table 13 – Minimum PSACR values for permanent link
Frequency Minimum ACR
dB
MHz
Class D
1,0 56,1
4,0 44,7
10,0 36,4
16,0 31,5
20,0 29,0
31,25 23,6
62,5 13,7
100,0 5,7
Table 14 – Minimum PSACR values for channels

Frequency Minimum ACR
dB
MHz
Class D
1,0 54,8
4,0 43,1
10,0 34,0
16,0 28,4
20,0 25,7
31,25 19,9
62,5 9,1
100,0 0,1
11801 Amend. 2 © ISO/IEC:1999(E) – 15 –

7.3.7 ELFEXT
7.3.7.1 Pair-to-pair ELFEXT
The ELFEXT shall be measured from both ends to allow a correct evaluation of the permanent

link or channel.
Table 15 – Minimum ELFEXT values for permanent link

Frequency Minimum ELFEXT
dB
MHz
Class D
1,0 59,6
4,0 47,6
10,0 39,6
16,0 35,5
20,0 33,6
31,25 29,7
62,5 23,7
100,0 19,6
Table 16 – Minimum ELFEXT values for channels
Frequency Minimum ELFEXT
dB
MHz
Class D
1,0 57,0
4,0 45,0
10,0 37,0
16,0 32,9
20,0 31,0
31,25 27,1
62,5 21,1
100,0 17,0
7.3.7.2 Power Sum ELFEXT
The PSELFEXT parameter is applicable to class D only. The PSELFEXT of a class D
permanent link and channel shall meet or exceed the values shown in tables 17 and 18
respectively. PSELFEXT is computed from pair-to-pair ELFEXT as follows:
−ELFEXT −ELFEXT −ELFEXT
pp,1 pp,2 pp,3
 
 
10 10 10
PSELFEXT = −10 log 10 + 10 + 10
 
 
– 16 – 11801 Amend. 2 © ISO/IEC:1999(E)

Table 17 – Minimum Power Sum ELFEXT values for permanent link

Frequency Min
...