IEC 60512-28-100:2013

IEC 60512-28-100 ®
Edition 1.0 2013-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Connectors for electronic equipment – Tests and measurements –
Part 28-100: Signal integrity tests up to 1 000 MHz on IEC 60603-7 and
IEC 61076-3 series connectors – Tests 28a to 28g

Connecteurs pour équipements électroniques – Essais et mesures –
Partie 28-100: Essais d'intégrité des signaux jusqu'à 1 000 MHz sur les
connecteurs des séries CEI 60603-7 et CEI 61076-3 – Essais 28a à 28g

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IEC 60512-28-100 ®
Edition 1.0 2013-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Connectors for electronic equipment – Tests and measurements –

Part 28-100: Signal integrity tests up to 1 000 MHz on IEC 60603-7 and

IEC 61076-3 series connectors – Tests 28a to 28g

Connecteurs pour équipements électroniques – Essais et mesures –

Partie 28-100: Essais d'intégrité des signaux jusqu'à 1 000 MHz sur les

connecteurs des séries CEI 60603-7 et CEI 61076-3 – Essais 28a à 28g

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 31.220.10 ISBN 978-2-83220-639-3

– 2 – 60512-28-100 © IEC:2013
CONTENTS
FOREWORD . 5

1 Scope . 7

2 Normative references . 7

3 Terms, definitions and acronyms . 8

3.1 Terms and definitions . 8

3.2 Acronyms . 8

4 Overall test arrangement . 9

4.1 Test instrumentation . 9
4.2 Measurement precautions . 9
4.3 Mixed mode S-parameter nomenclature . 10
4.4 Coaxial cables and interconnect for network analysers . 11
4.5 Requirements for switching matrices . 11
4.6 Test fixture requirements . 12
4.7 Requirements for termination performance at calibration plane. 13
4.8 Reference loads for calibration . 13
4.9 Calibration . 14
4.10 Termination loads for termination of conductor pairs . 14
4.10.1 General . 14
4.10.2 Verification of termination loads . 15
4.11 Termination of screens . 15
4.12 Test specimen and reference planes . 15
4.12.1 General . 15
4.12.2 Interconnections between device under test (DUT) and the
calibration plane . 16
4.13 Overall test setup requirements . 18
5 Connector measurement up to 1 000 MHz . 18
5.1 General . 18
5.2 Insertion loss, Test 28a . 19
5.2.1 Object. 19
5.2.2 Connecting hardware insertion loss . 19
5.2.3 Test method . 19
5.2.4 Test set-up . 19

5.2.5 Procedure . 19
5.2.6 Test report . 20
5.2.7 Accuracy . 20
5.3 Return loss, Test 28b . 20
5.3.1 Object. 20
5.3.2 Connecting hardware return loss . 20
5.3.3 Test method . 20
5.3.4 Test set-up . 21
5.3.5 Procedure . 21
5.3.6 Test report . 21
5.3.7 Accuracy . 21
5.4 Near-end crosstalk (NEXT), Test 28c . 21
5.4.1 Object. 21
5.4.2 Connecting hardware NEXT . 21

60512-28-100 © IEC:2013 – 3 –
5.4.3 Test method . 21

5.4.4 Test set-up . 22

5.4.5 Procedure . 22

5.4.6 Test report . 23

5.4.7 Accuracy . 23

5.5 Far-end crosstalk (FEXT), Test 28d . 23

5.5.1 Object. 23

5.5.2 Connecting hardware FEXT . 23

5.5.3 Test method . 23

5.5.4 Test set-up . 23

5.5.5 Procedure . 24
5.5.6 Test report . 24
5.5.7 Accuracy . 24
5.6 Transfer impedance (Z ), Test 28e . 25
T
5.7 Transverse conversion loss (TCL), Test 28f. 25
5.7.1 Object. 25
5.7.2 Connecting hardware TCL . 25
5.7.3 Test method . 25
5.7.4 Test set-up . 25
5.7.5 Procedure . 25
5.7.6 Test report . 26
5.7.7 Accuracy . 26
5.8 Transverse conversion transfer loss (TCTL), Test 28g . 26
5.8.1 Object. 26
5.8.2 Connecting hardware TCTL . 26
5.8.3 Test method . 27
5.8.4 Test set-up . 27
5.8.5 Procedure . 27
5.8.6 Test report . 27
5.8.7 Accuracy . 27
5.9 Coupling attenuation . 28
Annex A (informative) Example derivation of mixed mode parameters using the modal
decomposition technique . 29
Annex B (informative) Test pins – Dimensions and references . 32
Bibliography . 33

Figure 1 – Diagram of a single ended 4 port device . 10
Figure 2 – Diagram of a balanced 2 port device . 10
Figure 4 – Calibration of reference loads . 14
Figure 5 – Resistor termination networks . 15
Figure 6 – Definition of reference planes . 16
Figure 7 – Insertion loss and TCTL measurement . 20
Figure 8 – NEXT measurement . 22
Figure 9 – FEXT measurement . 24
Figure 10 – Return loss and TCL measurement . 25
Figure A.1 – Voltage and current on balanced DUT. 29
Figure A.2 – Voltage and current on unbalanced DUT . 30

– 4 – 60512-28-100 © IEC:2013
Figure B.1 – Example of pin and fixed connector dimensions . 32

Table 1 – Mixed mode S-parameter nomenclature . 11

Table 2 – Switch performance recommendations . 12

Table 3 – Test fixture requirements . 13

Table 4 – Requirements for terminations at calibration plane . 13

Table 5 – Interconnection DM return loss requirements. 18

Table 6 – Overall test setup requirements . 18

60512-28-100 © IEC:2013 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
CONNECTORS FOR ELECTRONIC EQUIPMENT –

TESTS AND MEASUREMENTS –
Part 28-100: Signal integrity tests up to 1 000 MHz

on IEC 60603-7 and IEC 61076-3 series connectors –

Tests 28a to 28g
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, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60512-28-100 has been prepared by subcommittee 48B:
Connectors, of IEC technical committee 48: Electromechanical components and mechanical
structures for electronic equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
48B/2322/FDIS 48B/2332/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – 60512-28-100 © IEC:2013
A list of all parts of IEC 60512 series, under the general title Connectors for electronic

equipment – Tests and measurements, can be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be

• reconfirmed,
• withdrawn,
• replaced by a revised edition, or

• amended.
60512-28-100 © IEC:2013 – 7 –
CONNECTORS FOR ELECTRONIC EQUIPMENT –

TESTS AND MEASUREMENTS –
Part 28-100: Signal integrity tests up to 1 000 MHz

on IEC 60603-7 and IEC 61076-3 series connectors –

Tests 28a to 28g
1 Scope
This part of IEC 60512 specifies the test methods for transmission performance for
IEC 60603-7 and IEC 61076-3 series connectors up to 1 000 MHz. It is also suitable for
testing lower frequency connectors, however the test methodology specified in the detailed
specification for any given connector remains the reference conformance test for that
connector.
The test methods provided here are:
– insertion loss, test 28a;
– return loss, test 28b;
– near-end crosstalk (NEXT) test 28c;
– far-end crosstalk (FEXT), test 28d;
– transverse conversion loss (TCL), test 28f;
– transverse conversion transfer loss (TCTL), test 28g.
For the transfer impedance (ZT) test, see IEC 60512-26-100, test 26e.
For the coupling attenuation, see IEC 62153-4-12.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60050-581, International Electrotechnical Vocabulary (IEV) – Part 581: Electromechanical
components for electronic equipment
IEC 60512-1, Connectors for electronic equipment – Tests and measurements – Part 1:
General
IEC 60512-26-100:2008, Connectors for electronic equipment – Tests and measurements –
Part 26-100: Measurement setup, test and reference arrangement and measurements for
connectors according to IEC 60603-7 – Tests 26a to 26g
IEC 60603-7 (all parts), Connectors for electronic equipment
IEC 61076-1, Connectors for electronic equipment – Product requirements – Part 1: Generic
specification
– 8 – 60512-28-100 © IEC:2013
IEC 61076-3-104, Connectors for electronic equipment – Product requirements –

Part 3-104: Detail specification for 8-way, shielded free and fixed connectors for data

transmissions with frequencies up to 1 000 MHz

IEC 61076-3-110, Connectors for electronic equipment – Product requirements –

Part 3-110: Detail specification for shielded, free and fixed connectors for data transmission

with frequencies up to 1 000 MHz

IEC 61156 (all parts), Multicore and symmetrical pair/quad cables for digital communications

IEC 61156-6, Multicore and symmetrical pair/quad cables for digital communications – Part 6:

Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz – Work area
wiring – Sectional specification
IEC 61169-16, Radio-frequency connectors – Part 16: RF coaxial connectors with inner
diameter of outer conductor 7 mm (0,276 in) with screw coupling – Characteristic impedance
50 ohms (75 ohms) (Type N)
IEC 62153-4-12, Metallic communication cable test methods – Part 4-12: Electromagnetic
compatibility (EMC) – Coupling attenuation or screening attenuation of connecting hardware –
Absorbing clamp method
ISO/IEC 11801, Information technology – Generic cabling for customer premises
3 Terms, definitions and acronyms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions of IEC 60050(581), IEC 61076-1,
IEC 60512-1, IEC 60603-7, IEC 61076-3-104 and IEC 61076-3-110 as well as the following,
apply.
3.1.1
mixed mode (parameter or measurement)
parameters or measurements containing differential mode, common mode, and intermodal
S-matrices
3.1.2
intermodal (parameter or measurement)
a parameter or measurement that either sources on the common mode and measures on the
differential mode or, sources on the differential mode and measures on the common mode

3.2 Acronyms
For ease of reference acronyms used in this document are given below.
CM common mode
DM differential mode
DUT device under test
FEXT far-end crosstalk loss
IEC International Electrotechnical Commission
LCL longitudinal conversion loss
LCTL longitudinal conversion transfer loss
NEXT near-end crosstalk loss
TCL transverse conversion loss

60512-28-100 © IEC:2013 – 9 –
TCTL transverse conversion transfer loss

SE single ended
Z transfer impedance
T
4 Overall test arrangement
4.1 Test instrumentation
All test instrumentation shall be capable of performing measurements over the frequency

range of 1 MHz to 1 000 MHz.
The test procedures hereby described require the use of a vector network analyser. The
analyser should have the capability of full 2-port calibrations. The analyser shall cover the
frequency range of 1 MHz to 1 000 MHz at least.
Measurements are to be taken using a mixed mode test set-up, which is often referred to as
an unbalanced, modal decomposition or balun-less setup. This allows measurements of
balanced devices without use of an RF balun in the signal path.
Such a configuration also allows testing with either a common or differential mode stimulus
and responses, ensuring that intermodal parameters can be measured without reconnection.
A 16 port network analyser is required to measure all combinations of a 4 pair device without
external switching, however the network analyser shall have a minimum of 2 ports (including
one bi-directional port) to enable the data to be collated and calculated.
It should be noted that the use of a 2 port analyser will involve successive repositioning of the
measurement port in order to measure any given parameter.
A 4 port network analyser is recommended as a practical minimum number of ports, as this
will allow the measurement of the full 16 term mixed mode S-parameter matrix on a given pair
combination without switching or reconnection in one direction.
In order to minimise the reconnection of the DUT for each pair combination the use of an
RF switching unit is also recommended.
Each conductor of the pair or pair combination under test shall be connected to a separate
port of the network analyser, and results are processed either by internal analysis within the
network analyser or by an external application.

Reference loads and through connections are needed for the calibration of the set-up.
Requirements for the reference loads are given in 4.8. Termination loads are needed for
termination of pairs, used and unused, which are not terminated by the network analyser.
Requirements for the termination loads are given in 4.7 and 4.10.
4.2 Measurement precautions
To ensure a high degree of reliability for transmission measurements, the following
precautions are required.
a) Consistent and stable resistor loads shall be used throughout the test sequence.
b) Cable and adapter discontinuities, as introduced by physical flexing, sharp bends and
restraints shall be avoided before, during and after the tests.
c) Consistent test methodology and termination resistors shall be used at all stages of
transmission performance qualifications.

– 10 – 60512-28-100 © IEC:2013

The relative spacing of conductors in the pairs shall be preserved throughout the tests to

the greatest extent possible.
d) The balance of the cables shall be maintained to the greatest extent possible by

consistent conductor lengths and pair twisting to the point of load.

e) The sensitivity to set-up variations for these measurements at high frequencies demands
attention to details for both the measurement equipment and the procedures.

4.3 Mixed mode S-parameter nomenclature

The test methods specified in this standard are based on a balun-less test setup in which all

terminals of a device under test are measured and characterized as single ended (SE) ports,

i.e. signals (RF voltages and currents) are defined relative to a common ground. For a device
with 4 terminals, a diagram is given in Figure 1.

Port 1 Port 3
Port 2 DUT Port 4
IEC  338/13
Figure 1 – Diagram of a single ended 4 port device
The 4 port device in Figure 1 is characterized by the 16 term SE S-matrix given in Formula 1,
in which the S-parameter S expresses the relation between a single ended response on port
ba
“b” resulting from a single ended stimulus on port “a”.
S S S S
 
11 12 13 14
 
S S S S
21 22 23 24
 
S=
(1)
S S S S 
31 32 33 34
 
S S S S
41 42 34 44
 
For a balanced device, each port is considered to consist of a pair of terminals (= a balanced
port) as opposed to the SE ports defined above, see Figure 2.

Port 1 Port 2
DUT
(balanced)
IEC  339/13
.
Figure 2 – Diagram of a balanced 2 port device
In order to characterize the balanced device, both the differential mode and the common
mode signals on each balanced port shall be considered. The device can be characterized by
a mixed mode S-matrix that includes all combinations of modes and ports, e.g. the mixed
that expresses the relation between a differential mode response on
mode S-parameter S
DC21
60512-28-100 © IEC:2013 – 11 –

port 2 resulting from a common mode stimulus on port 1. Using this nomenclature, the full set

of mixed mode S-parameters for a 2-port can be presented as in Table 1.

Table 1 – Mixed mode S-parameter nomenclature

Differential mode Common mode
stimulus stimulus
Port 1 Port 2 Port 1 Port 2
Differential Port 1 S S S S
DD11 DD12 DC11 DC12
mode
Port 2 S S S S
response
DD21 DD22 DC21 DC22
Common  Port 1 S S S S
CD11 CD12 CC11 CC12
mode
Port 2 S S S S
response
CD21 CD22 CC21 CC22
A 4 terminal device can be represented both as a 4 port SE device as in Figure 1
characterized by a single ended S-matrix (Formula 1) and as a 2 port balanced device as in
Figure 2 characterized by a mixed mode S-matrix (Table 1). As applying a SE signal to a port
is mathematically equivalent to applying superposed differential and common mode signals,
the SE and the mixed mode characterizations of the device are interrelated. The conversion
from SE to mixed mode S-parameters is given in Annex A. Making use of this conversion, the
mixed mode S-parameters may be derived from the measured SE S-matrix.
4.4 Coaxial cables and interconnect for network analysers
Assuming that the characteristic impedance of the network analyser is 50 Ω, coaxial cables
used to interconnect the network analyser, switching matrix and the test fixture shall be of
50 Ω characteristic impedance and of low transfer impedance (double screen or more).
These coaxial cables should be as short as possible. (It is recommended that they do not
exceed 1 000 mm each.)
The screens of each cable shall be electrically bonded to a common ground plane.
To optimize dynamic range, the total interconnecting cable insertion loss should be less than
3 dB at 1 000 MHz.
4.5 Requirements for switching matrices
Switches (if used) shall be of a minimum of 2x4 configuration, although a switch with a higher
number of ports (e.g. 2x8, 1x16) is recommended as this can allow more complete or even
total measurement of the DUT without reconnection or moving the DUT. When such switching

is used, it shall be constructed such that each port be configurable as either input, output or
50 Ω termination. All inactive ports of the switch shall be terminated with a 50 Ω impedance
load.
The switch shall be capable of swapping the ports of the network analyser in a paired fashion
to correctly connect to each conductor of the DUT transmission pair.
The switch should be constructed to minimise the different path lengths for each signal path
of the pair.
The switch shall comply to the minimum switch performance recommendations given by
Table 2.
– 12 – 60512-28-100 © IEC:2013

Table 2 – Switch performance recommendations

Frequency
Parameter Requirement up to 1 000 MHz

MHz
Insertion loss (dB)
≤ 0,5 dB
≥68-20log(f) dB
Return loss (dB) 1 ≤ f ≤ 1 000) 40 dB max

24 dB min
Crosstalk (dB)
≥ 95 dB
4.6 Test fixture requirements
For ease of interfacing to test fixtures, a pin and fixed connector interface with dimensions as
shown in Figure 3 is recommended. Information concerning examples of fixed connectors that
may be used for this interface is given in Annex B.
Dimensions in millimeters
2,54
NOTE 1
NOTE 4
NOTE 3
NOTE 2
1,27
IEC  340/13
NOTE 1 Ground
NOTE 2 Ground
NOTE 3 First conductor in a pair
NOTE 4 Second conductor in a pair
Figure 3 – Test interface pattern
Test fixtures shall meet the requirements of Table 3 when tested using appropriate resistor
terminations at the DUT interface fixed connectors of the fixture after the network analyser
has been calibrated at the end of the coaxial cables intended to interface to the fixture.

2,21
4,42
60512-28-100 © IEC:2013 – 13 –

Table 3 – Test fixture requirements

Parameter Frequency Requirement up to 1 000 MHz

MHz
≥72-20log(f) dB
SE Port (50 Ω) return loss (dB)
40 dB max
≥78-20log(f) dB
DM port (100 Ω) return loss (dB)

40 dB max
≥68-20log(f) dB
CM port (100 Ω) return loss (dB)
35 dB max
≥114-20log(f) dB
SE (50 Ω) Port to Port Isolation NEXT and FEXT
75 dB max
1 ≤ f ≤ 1 000
≥130-20log(f) dB
DM (100 Ω) Port to Port Isolation NEXT and FEXT pair to pair
94 dB max
DM (100 Ω) insertion loss < 0,5 dB
≥100-20log(f) dB
TCL LCL
70 dB max
≥90-20log(f) dB
TCTL LCTL
50 dB max
4.7 Requirements for termination performance at calibration plane
Termination performance at the calibration plane shall meet the requirements of Table 4.
Table 4 – Requirements for terminations at calibration plane
Parameter Frequency Requirement up to 1 000 MHz
MHz
≥74-20log(f) dB
SE Port (50 Ω) return loss (dB)
40 dB max
≥74-20log(f) dB
DM port (100 Ω) return loss (dB) 1 ≤ f ≤ 1 000
40 dB max
≥130-20log(f) dB
DM Port to Port residual NEXT
94 dB max
4.8 Reference loads for calibration
To perform a one or two-port calibration of the test equipment, a short circuit, an open circuit
and a reference load are required. These devices shall be used to obtain a calibration.
The reference load shall be calibrated against a calibration reference, which shall be a 50 Ω
load, traceable to an international reference standard. One 50 Ω reference load shall be
calibrated against the calibration reference. The reference load for calibration shall be placed
in an N-type connector according to IEC 61169-16, meant for panel mounting, which is
machined flat on the back side, see Figure 4.
The load shall be fixed to the flat side of the connector. A network analyser shall be
calibrated, 1-port full calibration, with the calibration reference. Thereafter, the return loss of
the reference load for calibration shall be measured. The verified return loss shall be >46 dB
at frequencies up to 100 MHz and >40 dB at frequencies above 100 MHz and up to the limit
for which the measurements are to be carried out.

– 14 – 60512-28-100 © IEC:2013

Machined flat
Load for calibration
N type connector
IEC  341/13
Figure 4 – Calibration of reference loads
4.9 Calibration
Isolation measurements shall be used as part of the calibration.
The calibration shall be equivalent to a minimum of a full 2-port SE calibration for
measurements where the response and stimulus ports are the same (Sxx11 and Sxx22), and
a minimum of a full 4 port SE calibration for measurements where the response and stimulus
ports are different (Sxx12 and Sxx21).
An individual calibration shall be performed for each signal path used for the measurements.
If a complete switching matrix and 4-port network analyser test setup is used, a full set of
measurements for a 4 pair device (i.e. 16 single-ended ports), will require 28 separate 4-port
calibrations, although many of the measurements within each calibration are in common with
other calibrations. A software or hardware package may be used to minimise the number of
calibration measurements required.
The calibration shall be applied such that the calibration plane shall be at the ends of the
fixed connectors of the test fixture.
The calibration may be performed at the test interface using appropriate calibration artefacts,
or at the ends of the coaxial test cable using coaxial terminations.
Where calibration is performed at the test interface, open, short and load measurements shall
be taken on each SE port concerned, and through and isolation measurements shall be taken
on every pair combination of those ports.
Where calibration is performed at the end of the coaxial test cables, open, short and load
measurements shall be taken on each port concerned, and through and isolation

measurements shall be taken on every pair combination of those ports. In addition, the test
fixture shall then be de-embedded from the measurements. The de-embedding techniques
shall incorporate a fully populated 16 port S-matrix. It is not acceptable to perform a de-
embedded calibration using only reflection terms (S , S , S , S ) or only near end terms
11 22 33 44
(S ,S ,S , S ).
11 21 12 22
De-embedding using reduced term S-matrices may be used for post-processing of results.
4.10 Termination loads for termination of conductor pairs
4.10.1 General
50 Ω wire to ground terminations shall be used on all active pairs under test. 50 Ω differential
mode to ground terminations shall be used on all inactive pairs and on the opposite ends of
active pairs for NEXT and FEXT testing. Inactive pairs for return loss testing shall be
terminated with 50 Ω differential mode to ground terminations. See Figure 5.

60512-28-100 © IEC:2013 – 15 –

50 Ω ± 0,1 %
50 Ω ± 0,1 %
50 Ω differential mode to
ground terminations
IEC  342/13
Figure 5 – Resistor termination networks

Small geometry chip resistors shall be used for the construction of resistor terminations. The
two 50 Ω DM terminating resistors shall be matched to within 0,1 % at DC, and 2% at 1
000 MHz (corresponding to a 40dB Return loss requirement at 1 000 MHz). The length of
connections to impedance terminating resistors shall be minimized. Use of soldered
connections without leads is recommended.
4.10.2 Verification of termination loads
The performance of impedance matching resistor termination networks shall be verified by
measuring the return loss of the termination and the residual NEXT between any two resistor
termination networks at the calibration plane.
For the return loss measurement, a two port SE calibration is required using a reference load
verified according to 4.8.
After calibration, connect the resistor termination network and perform a full two port SE S-
matrix measurement. The measured SE S-matrix shall be transformed into the associated
mixed mode S-matrix to obtain the S-parameters S and S from which the differential
DD11 CC11
mode return loss RL and the common mode return loss RL are determined. The return
DM CM
loss of the resistor termination network shall meet the requirements of Table 4.
For the residual NEXT measurement, a four port SE calibration is required. After calibration,
connect the resistor termination networks and perform a full four port SE S-matrix
measurement. The measured S-matrix shall be transformed into the associated mixed mode
S-matrix to obtain the S-parameter S from which the residual NEXT of the terminations,
DD21
NEXT , is determined. The residual NEXT shall meet the requirements of Table 4.
residual_term
4.11 Termination of screens
If the connector under test is screened, screened measurement cables shall be applied.

The screen or screens of these cables shall be fixed to the ground plane as close as possible
to the calibration plane.
4.12 Test specimen and reference planes
4.12.1 General
The test specimen is a mated pair of relevant connectors. The connector reference plane for
the test specimen is the point at which the cable sheath enters the connector (the back end of
the connector) or the point at which the internal geometry of the cable is no longer
maintained, whichever is farther from the connector, see Figure 6. This definition applies to
both ends of the test specimen. The fixed connector shall be terminated in accordance with
the manufacturer’s instructions and shall be compatible with the measurement test set up and
fixtures.
– 16 – 60512-28-100 © IEC:2013

Plug side Socket side
Connector reference planes
IEC  343/13
Figure 6 – Definition of reference planes
4.12.2 Interconnections between device under test (DUT) and the calibration plane
4.12.2.1 General
Twisted-pair interconnect, printed circuits or other interconnections are used between the
connector reference plane of the DUT and the calibration plane. It is necessary to control the
characteristics of these interconnections to the best extent possible as they are beyond the
calibration plane. These interconnections should be as short as practical and their CM and
DM impedances shall be managed to minimize their effects on measurement. Refer to
Annex B for additional information about test pins which may be used to facilitate impedance
management.
The return loss performance of the interconnections shall meet the requirements of Table 5.
The insertion loss performance of the interconnections is assumed to be less than 0,1 dB over
the frequ
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