IEC 63171:2025

IEC 63171 ®
Edition 2.0 2025-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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

Connecteurs pour équipements électriques et électroniques – Fiches et
embases écrantées ou non écrantées pour transmission de données sur une
seule paire symétrique avec courant admissible – Exigences générales et essais

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IEC 63171 ®
Edition 2.0 2025-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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

Connecteurs pour équipements électriques et électroniques – Fiches et

embases écrantées ou non écrantées pour transmission de données sur une

seule paire symétrique avec courant admissible – Exigences générales et

essais
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.220.10  ISBN 978-2-8327-0337-3

– 2 – IEC 63171:2025 © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 10
4 Common features and typical connector pair . 10
5 Characteristics . 11
5.1 General . 11
5.2 Pin assignment . 11
5.3 Temperature-related tests . 11
5.3.1 Classification into climatic category . 11
5.3.2 Rapid change of temperature . 12
5.3.3 Creepage and clearance distances . 12
5.3.4 Voltage proof . 12
5.3.5 Current-temperature derating. 13
5.3.6 Interface contact resistance – initial only . 14
5.3.7 Input to output DC resistance . 14
5.3.8 Input to output DC resistance unbalance . 15
5.3.9 Insulation resistance . 15
5.4 Transmission characteristics (data transmission portion for a combined
connector) . 15
5.4.1 General . 15
5.4.2 Insertion loss . 16
5.4.3 Return loss . 16
5.4.4 Propagation delay . 17
5.4.5 Transverse conversion loss (unshielded only) . 17
5.4.6 Transverse conversion transfer loss (unshielded only) . 18
5.4.7 Transfer impedance (shielded only) . 18
5.4.8 Coupling attenuation (shielded only) . 18
5.4.9 Power sum alien (exogenous) NEXT . 19
5.4.10 Power sum alien (exogenous) FEXT . 20
5.5 Mechanical characteristics (data transmission portion for a combined
connector) . 20
5.5.1 General . 20
5.5.2 Mechanical operation . 20
5.5.3 Effectiveness of connector coupling devices . 21
5.5.4 Insertion and withdrawal forces . 22
5.5.5 Polarizing method . 22
5.5.6 Vibration . 22
5.5.7 Shock . 22
6 Tests and test schedule . 23
6.1 General . 23
6.2 Example of an arrangement for input to output DC resistance measurement . 24
6.3 Example of an arrangement for interface contact resistance measurement . 25
6.4 Arrangement for vibration test (test phase DP) . 26
6.5 Test procedures and measuring methods . 26
6.6 Preconditioning . 26

6.7 Test schedules. 26
6.7.1 General . 26
6.7.2 Basic (minimum) test schedule . 26
6.7.3 Full test schedule . 26
Annex A (informative) Current product detail specifications. 35
Annex B (informative) Relationship between connector categories and application
references of IEEE . 39
Bibliography . 40

Figure 1 – Relationship between the IEC 63171 series and their related references. 7
Figure 2 – Example of front view of fixed connector pin assignment . 11
Figure 3 – Level I connector derating curve . 13
Figure 4 – Level II connector derating curve . 14
Figure 5 – Example of an arrangement for input to output DC resistance measurement . 24
Figure 6 – Example of arrangement for contact resistance measurement . 25

Table 1 – Climatic categories – selected values . 11
Table 2 – Maximum insertion loss . 16
Table 3 – Minimum return loss . 17
Table 4 – Minimum transverse conversion loss (unshielded only) . 17
Table 5 – Minimum transverse conversion transfer loss (unshielded only). 18
Table 6 – Maximum transfer impedance (shielded only) . 18
Table 7 – Minimum coupling attenuation (shielded only) . 19
Table 8 – Minimum power sum alien near end crosstalk (PS ANEXT) . 19
Table 9 – Minimum power sum alien far end crosstalk (PS AFEXT) . 20
Table 10 – Preferred values for the number of mating cycles . 21
Table 11 – Minimum pull-out force . 21
Table 12 – Test group P . 27
Table 13 – Test group AP . 28
Table 14 – Test group BP . 30
Table 15 – Test group CP . 31
Table 16 – Test group DP . 32
Table 17 – Test group EP . 33
Table 18 – Test group FP . 33
Table 19 – Test group GP . 34
Table A.1 – Overview of current product detail specifications . 36
Table B.1 – Overview of connector categories and application references of IEEE . 39

– 4 – IEC 63171:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
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

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 this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 63171 has been prepared by subcommittee 48B: Electrical connectors, of IEC technical
committee 48: Electrical connectors and mechanical structures for electrical and electronic
equipment. It is an International Standard.
This second edition cancels and replaces the first edition published in 2021. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) added requirements related to multipole and combined connectors (that are connectors
including multiple data modules of this series, or connectors including one data module and
additional signal or power contacts);
b) alignment of transmission requirements with ISO/IEC 11801-1;

c) updating and reorganising of test groups.
The text of this International Standard is based on the following documents:
Draft Report on voting
48B/3150/FDIS 48B/3157/RVD
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 International Standard 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 ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 63171:2025 © IEC 2025
INTRODUCTION
This document, identified as IEC 63171, provides the general requirements and general tests
(general specification) of the whole IEC 63171 series, a set of International Standards covering
shielded or unshielded free and fixed connectors for balanced single-pair data transmission
with current-carrying capacity.
It provides the signal integrity requirements, common to the whole series.
Subsequent parts, identified as IEC 63171 followed by a dash and a progressive number
starting with 1, are the product detail specifications of this series; see Annex A, and do not
duplicate information given in this document, but list only additional requirements.
Each subsequent part is identified by a type of connector – or a set of connectors – covered
with the same number identifying the part. Some parts can describe more connector geometries
(rectangular, circular), sharing the core element and the relevant features.
Other requirements, which are necessary to describe e.g., additional power portion – if any –
of that connector, can be covered by referencing requirements provided by other relevant
documents, e.g.: IEC 61076-2 series, IEC 61076-3, or IEC 61984, as applicable.
For the complete specifications regarding a connector of this series, as well as of other series
calling up this document for the signal integrity requirements, both this product general
specification and the relevant product detail specification, see Annex A, as well as any other
sectional specification or safety requirement document referenced in the relevant subsequent
part of this series or in the relevant product detail specification, see Annex A, are therefore
required.
For the qualification of a connector of this series, all the requirements according to this general
specification and the relevant product detail specification, see Annex A, – including the
references made therein, if any, to other sectional specification or other safety-related
documents – are met.
Figure 1 shows the interrelation of the standards within this series:

Figure 1 – Relationship between the IEC 63171 series and their related references

– 8 – IEC 63171:2025 © IEC 2025
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

1 Scope
This document covers shielded or unshielded free and fixed connectors, circular or rectangular,
for balanced single-pair data transmission, with current-carrying capacity.
It also covers the portion for balanced single-pair data transmission of combined, shielded or
unshielded, free and fixed connectors, circular or rectangular, having additional contacts for
power transmission, whose performance requirements are described in a product detail
specification, see Annex A, of the IEC 63171-X series, (type X connectors), or in a separate
document, either an IEC product detail specification, see Annex A, or manufacturer's
specification.
This document does not describe a specific mating interface. It specifies the IEC 63171 series
– or other documents referencing it – common mechanical, electrical and transmission
characteristics and environmental requirements, as well as required test specifications.
Within their own type, the shielded and unshielded connectors are interoperable for their
transmission performance and can be exchanged, although the shielded version has improved
alien crosstalk and coupling attenuation properties.
Single-pair connectors of this series can be grouped to one body of multipole connectors or
combined with other connectors, e.g., power connectors, also known as combined (data or
signal, and power) connectors.
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 60050-581, International Electrotechnical Vocabulary (IEV) – Part 581: Electromechanical
components for electronic equipment
IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60068-2-38, Environmental testing – Part 2-38: Tests – Test Z/AD: Composite
temperature/humidity cyclic test
IEC 60512-1, Connectors for electrical and electronic equipment – Tests and measurements –
Part 1: Generic specification
IEC 60512-1-1, Connectors for electronic equipment – Tests and measurements – Part 1-1:
General examination – Test 1a: Visual examination
IEC 60512-1-2, Connectors for electronic equipment – Tests and measurements – Part 1-2:
General examination – Test 1b: Examination of dimension and mass

IEC 60512-2-1, Connectors for electronic equipment – Tests and measurements – Part 2-1:
Electrical continuity and contact resistance tests – Test 2a: Contact resistance – Millivolt level
method
IEC 60512-2-5, Connectors for electronic equipment – Tests and measurements – Part 2-5:
Electrical continuity and contact resistance tests – Test 2e: Contact disturbance
IEC 60512-3-1, Connectors for electronic equipment – Tests and measurements – Part 3-1:
Insulation tests – Test 3a: Insulation resistance
IEC 60512-4-1, Connectors for electronic equipment – Tests and measurements – Part 4-1:
Voltage stress tests – Test 4a: Voltage proof
IEC 60512-5-2, Connectors for electronic equipment – Tests and measurements – Part 5-2:
Current-carrying capacity tests – Test 5b: Current-temperature derating
IEC 60512-6-3, Connectors for electronic equipment – Tests and measurements – Part 6-3:
Dynamic stress tests – Test 6c: Shock
IEC 60512-6-4, Connectors for electronic equipment – Tests and measurements – Part 6-4:
Dynamic stress tests – Test 6d: Vibration (sinusoidal)
IEC 60512-9-1, Connectors for electronic equipment – Tests and measurements – Part 9-1:
Endurance tests – Test 9a: Mechanical operation
IEC 60512-9-2, Connectors for electronic equipment – Tests and measurements – Part 9-2:
Endurance tests – Test 9b: Electrical load and temperature
IEC 60512-11-1, Connectors for electrical and electronic equipment – Tests and measurements
– Part 11-1: Climatic tests – Test 11a – Climatic sequence
IEC 60512-11-3, Connectors for electronic equipment – Tests and measurements – Part 11-3:
Climatic tests – Test 11c: Damp heat, steady state
IEC 60512-11-4, Connectors for electronic equipment – Tests and measurements – Part 11-4:
Climatic tests – Test 11d: Rapid change of temperature
IEC 60512-11-7, Connectors for electronic equipment – Tests and measurements – Part 11-7:
Climatic tests – Test 11g: Flowing mixed gas corrosion test
IEC 60512-11-9, Connectors for electronic equipment – Tests and measurements – Part 11-9:
Climatic tests – Test 11i: Dry heat
IEC 60512-13-2, Connectors for electronic equipment – Tests and measurements – Part 13-2:
Mechanical operation tests – Test 13b: Insertion and withdrawal forces
IEC 60512-13-5, Connectors for electronic equipment – Tests and measurements – Part 13-5:
Mechanical operation tests – Test 13e: Polarizing and keying method
IEC 60512-15-6, Connectors for electronic equipment – Tests and measurements – Part 15-6:
Connector tests (mechanical) – Test 15f: Effectiveness of connector coupling devices
IEC 60512-15-7, Connectors for electronic equipment – Tests and measurements – Part 15-7:
Connector tests (mechanical) – Test 15g: Robustness of protective cover attachment

– 10 – IEC 63171:2025 © IEC 2025
IEC 60512-25-9, Connectors for electronic equipment – Tests and measurements – Part 25-9:
Signal integrity tests – Test 25i: Alien crosstalk
IEC 60512-26-100, Connectors for electronic equipment – Tests and measurements – Part 26-
100: Measurement setup, test and reference arrangements and measurements for connectors
according to IEC 60603-7 – Tests 26a to 26g
IEC 60512-28-100, Connectors for electrical and electronic equipment – Tests and
measurements – Part 28-100: Signal integrity tests up to 2 000 MHz – Tests 28a to 28g
IEC 60664-1, Insulation coordination for equipment within low-voltage supply systems – Part 1:
Principles, requirements and tests
IEC 61156 (all parts), Multicore and symmetrical pair/quad cables for digital communications
IEC 61984, Connectors – Safety requirements and tests
IEC 62153-4-9, Metallic communication cable test methods – Part 4-9: Electromagnetic
compatibility (EMC) – Coupling attenuation of screened balanced cables, triaxial method
IEC 62153-4-15, Metallic cables and other passive components test methods – Part 4-15:
Electromagnetic compatibility (EMC) – Test method for measuring transfer impedance and
screening attenuation or coupling attenuation with triaxial cell
ISO/IEC 11801-1, Information technology – Generic cabling for customer premises – Part 1:
General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-581 and
IEC 60512-1, and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
shield contact resistance
contact resistance between shield parts of fixed and free connectors
4 Common features and typical connector pair
This document provides general requirements and tests for shielded or unshielded, free and
fixed connectors for balanced single-pair data transmission with current carrying capacity.
Detail information of mating interfaces complying with this document can be found either in the
product detail specification standards IEC 63171-X (type X), see Annex A, or in the relevant
product detail specification, IEC or manufacturer's, claiming compliance with this document
regarding signal integrity requirements.
NOTE 1 More information related to M8 and M12 connectors, some of whose features are employed e.g., by type 5,
some of type 6, and type 7 connectors in this series, can be found respectively, in IEC 61076-2-104 and
IEC 61076-2-101.
NOTE 2 Further information's about single-pair cabling can be found in ISO/IEC TR 11801-9906,
ISO/IEC TR 11801-9911 and ISO/IEC 11801-1.
5 Characteristics
5.1 General
Conformance to the test schedules provided in 6.7 shall ensure the reliability of all performance
parameters, including transmission parameters, over the range of operating climatic conditions.
5.2 Pin assignment
For those specifications where pin assignment is relevant, the pin assignment shall be specified
as shown in Figure 2, unless otherwise specified. For those connector interfaces foreseeing
multiple instances of the same 2-way interface within the same connector body, the pin
assignment shall be specified for each of such individual 2-way interfaces.

Figure 2 – Example of front view of fixed connector pin assignment
5.3 Temperature-related tests
5.3.1 Classification into climatic category
The temperature range (range of operating temperature) and the assigned climatic category for
connectors complying with this document shall be compatible with ISO/IEC 11801-1
classification of a M I C E environment. Higher MICE classifications can be assigned in the
1 1 1 1
product detail specifications, see Annex A.
The upper temperature of the climatic category shall be compatible with the upper limiting
temperature (ULT) and the current-carrying capacity requirements of 5.3.5 (derating diagram in
Figure 3 or Figure 4, ULT ≥ 90 °C).
Table 1 – Climatic categories – selected values
Climatic category Lower temperature Upper temperature Damp heat, steady state
°C °C days
40/090/21 -40 90 21
NOTE As detailed in IEC 60068-1:2013, Annex A.

The category is indicated by a series of three groups of digits separated by oblique strokes
corresponding respectively to the temperature in the cold test and that in the dry heat test, and
the number of days of exposure to damp heat (steady state) the components will withstand, as
follows:
– First set: two digits denoting the minimum ambient temperature of operation (cold test).
Where the temperature requires the use of only one digit, it shall be prefixed by the figure

– 12 – IEC 63171:2025 © IEC 2025
"0" for a negative temperature or the symbol "+" for a positive temperature to make up the
two-character group.
– Second set: three digits denoting the maximum ambient temperature of operation (dry heat
test). Where the temperature requires the use of only two digits, they shall be prefixed by
the figure "0" to make up the three-digit group.
– Third set: two digits denoting the number of days of the damp heat, steady-state test (Test
CP2 in 6.7.3.5). Where the duration requires the use of only one digit, it shall be prefixed
by the figure "0" to make up the two-digit group. The figures "00" shall be used to indicate
that the component is not required to be exposed to damp heat (steady state).
In order to belong to a given category, components shall comply with the requirements of the
relevant specification when subjected to the complete set of tests prescribed for their category.
5.3.2 Rapid change of temperature
Conditions:
– IEC 60512-11-4, test 11d
– Mated connectors
– 25 cycles
– Upper and lower temperatures according to Table 1.
– T = 30 min
– Recovery time 2 h
5.3.3 Creepage and clearance distances
The permissible operating voltages depend on the application and the specified safety
requirements. Although insulation coordination is not required for safety aspects by the
connector covered in this document and in the relevant detail product specification, it is still
required for electrical functional requirements.
In general, for minimum values of clearances and creepage distances, IEC 60664-1 shall apply,
based on the assigned voltage rating for data connectors of 50 V AC and 60 V DC. For the
power portion of the connector, if any, clearances and creepage distances – within this portion
and between this portion and the data transmission portion – shall be in accordance with
IEC 60664-1 based on the declared rated voltage, rated impulse voltage and pollution degree
(see also IEC 61984).
NOTE As indicated in IEC 60664-1, IEC TR 63040 provides an alternative and more precise dimensioning
procedure for clearances equal to or less than 2 mm.
The creepage and clearance distances given in the relevant detail product specification apply
for mated connectors. The creepage and clearance distances that cover performance
requirements in IEC 60664-1 can be reduced, based on IEC TR 63040. Furthermore, in
practice, based on the conductive pattern of the printed board or the wiring used, reductions in
creepage or clearance distances are permitted.
5.3.4 Voltage proof
Conditions:
– IEC 60512-4-1, Test 4a, Method A.
– Standard atmospheric conditions.
– Mated connectors.
All data transmission portions:
– 1 000 V DC or AC peak: contact to contact.

– 1 500 V DC or AC peak: all contacts connected together, to shield (if applicable).
For the power portion of the connector, if any, the voltage proof requirement – within this portion
and between this and the data transmission portion – shall be in accordance with IEC 61984,
based on the declared rated voltage, rated impulse voltage and pollution degree.
NOTE For connector interfaces providing more than one individual 2-way shielded or unshielded connector, the test
is repeated on each of these individual connectors.
5.3.5 Current-temperature derating
Conditions:
– IEC 60512-5-2, Test 5b.
– All contacts connected in series.
– Testing shall be conducted with the minimum supported wire size.
– Testing shall be conducted at 60 °C with 1,25 times the value of the connector derating
curve of the level.
– The current-carrying capacity of the data transmission portions shall comply with the
derating values given in Figure 3 for Level I and Figure 4 for Level II.
NOTE For connector interfaces providing more than one individual 2-way shielded or unshielded connector, the
current-carrying capacity level provided either in Figure 3 (Level I) or in Figure 4 (Level II) is concurrently verified on
all of these individual connectors.

0,5
T

NOTE 1 The maximum permissible current for a given ambient temperature (T) is: I = 3,5×−1

(T)
90
NOTE 2 For ambient temperatures lower than 0 °C, the maximum permissible current per conductor is 3,5 A.
Figure 3 – Level I connector derating curve

– 14 – IEC 63171:2025 © IEC 2025

0,5
T

NOTE 1 The maximum permissible current for a given ambient temperature (T) is: I = 7,0×−1 .

(T)
90
NOTE 2 For ambient temperatures lower than 0 °C, the maximum permissible current per conductor is 7,0 A.
Figure 4 – Level II connector derating curve
For the power portion of the connector, if any, the current-temperature derating requirement –
when loaded concurrently with the data transmission portion – shall be as specified in the
relevant part of IEC 63171-X or any other product detail specification, see Annex A, or
manufacturer specification which calls up this document.
5.3.6 Interface contact resistance – initial only
Conditions:
– IEC 60512-2-1, Test 2a.
– Arrange for measurement in accordance with 6.3.
– Mated connectors.
– Measuring points: as specified in Figure 5.
– All data transmission portions: 20 mΩ maximum.
– Shielding resistance for data transmission portions: 50 mΩ maximum (if applicable).
For the power portion of the connector, if any, the interface contact resistance requirement shall
be as specified in the relevant part of IEC 63171-X or any other product detail specification,
see Annex A, or manufacturer specification which calls up this document.
5.3.7 Input to output DC resistance
Conditions:
– IEC 60512-2-1, Test 2a.
– Arrange for measurement in accordance with 6.3.
– Mated connectors.
– Measuring points: as specified in Figure 5.
– All data transmission portions: 50 mΩ maximum.
– Shielding resistance for data connector sections (if applicable): 100 mΩ maximum.
– Maximum change from initial value for all data transmission portions: 20 mΩ.
– Maximum change from initial value of shield contact between free and fixed connector data
connector sections, according to 5.3.6 (if applicable): 50 mΩ.
– Maximum change from initial value of shielding resistance for data connector sections (if
applicable): 100 mΩ
For the power portion of the connector, if any, the input to output DC resistance requirement
shall be as specified in the relevant part of IEC 63171-X or any other product detail
specification, see Annex A, or manufacturer specification which calls up this document.
5.3.8 Input to output DC resistance unbalance
Conditions:
– IEC 60512-2-1, Test 2a.
– Arrange for measurement in accordance with 6.3.
– Mated connectors.
– Measuring points: as specified in Figure 5.
– Among all signal conductors, maximum difference.
– All data transmission portions: 25 mΩ maximum.
For the power portion of the connector, if any, the input to output DC resistance unbalance
requirement shall be as specified in the relevant part of IEC 63171-X or any other product detail
specification, see Annex A, or manufacturer specification which calls up this document.
5.3.9 Insulation resistance
Conditions:
– IEC 60512-3-1, Test 3a, Method A.
– Mated connectors.
– Test voltage: 100 V DC.
– All data transmission portions: 500 MΩ minimum.
For the power portion of the connector, if any, the insulation resistance requirement shall be as
specified in the relevant part of IEC 63171-X or any other product detail specification, see
Annex A, or manufacturer specification which calls up this document.
5.4 Transmission characteristics (data transmission portion for a combined
connector)
5.4.1 General
This document specifies five different performance categories:
– Category A specified from 0,1 MHz to 20 MHz;
– Category B specified from 0,1 MHz to 600 MHz;
– Category C specified from 0,1 MHz to 1 250 MHz;
– Category D specified from 0,1 MHz to 2 500 MHz;
– Category E specified from 0,1 MHz to 4 000 MHz.

– 16 – IEC 63171:2025 © IEC 2025
Compliance with this document, with respect to transmission characteristics, shall be
determined in accordance with specified test methods described in test group FP.
All transmission performance requirements shall apply between the reference planes specified
in IEC 60512-28-100.
NOTE Test methods are only up to 2 GHz and Categories D and E are not covered under ISO/IEC 11801 series.
The relationship between the connector categories and the IEEE applications is described in
Annex B.
All transmission performance results shall be reported as worst-case overall result after
assessing all samples.
5.4.2 Insertion loss
Conditions:
– IEC 60512-28-100, test 28a.
– Mated connectors.
Requirements: According to Table 2.
Table 2 – Maximum insertion loss
Category Frequency Maximum insertion loss
MHz dB
A 0,1 to 20
0,02× f
B 0,1 to 600
0,02× f
C 0,1 to 1 250
0,02× f
D 0,1 to 2 500
0,02× f
E 0,1 to 4 000
0,02× f
Whenever the equation results in a value less than 0,1 dB, the requirement shall revert to
0,1 dB.
5.4.3 Return loss
Conditions:
– IEC 60512-28-100, test 28b.
– Mated connectors.
Requirements: According to Table 3.

Table 3 – Minimum return loss
Category Frequency Minimum return loss
MHz dB
A 0,1 to 20 48 – 20 log(f)
B 0,1 to 600 74 – 20 log(f)
C 0,1 to 1 250 74 – 20 log(f)
D 0,1 to 101 30
101 to 2 500
9
150−−22,3log f 100 10
( )


E 0,1 to 101 30
101 to 4 000
9
150−−22,3log f 100 10
( )


Whenever the equation results
...