oSIST prEN 3475-808:2026

• Abstract:

  This document specifies a method for measuring the cross-talk of a cable or between cables.

• Status: Not Published
• Public Enquiry End Date: 30-Oct-2026
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 21-Aug-2026
• Due Date: 08-Jan-2027
• Ref Project: prEN 3475-808 - Aerospace series - Cables, electrical, aircraft use - Test methods - Part 808: Cross-talk

• Replaces: SIST EN 3475-808:2004 - Aerospace series - Cables, electrical, aircraft use - Test methods - Part 808: Cross-talk
• Effective Date: 24-Aug-2022
• Revises: SIST EN 3475-808:2004 - Aerospace series - Cables, electrical, aircraft use - Test methods - Part 808: Cross-talk
• Effective Date: 19-Jan-2023
• Revised: SIST EN 3475-808:2004 - Aerospace series - Cables, electrical, aircraft use - Test methods - Part 808: Cross-talk
• Effective Date: 18-Jan-2023

oSIST prEN 3475-808:2026 is a CEN draft European Standard in the Aerospace series for electrical cables used in aircraft. It specifies how to measure cross-talk on a cable or between cables, so cable makers, test laboratories, and aerospace buyers can use one test method to compare results and check product limits.

What does oSIST prEN 3475-808:2026 specify?

oSIST prEN 3475-808:2026 specifies a method for measuring cross-talk on electrical aircraft cables and between cables. It covers both symmetrical (balanced) cables and coaxial cables, and it ties the final acceptance to the limits given in the relevant product standard.

The document is organized around one general method clause, separate method routes for symmetrical cables and coaxial cables, and a requirement clause. A normative annex gives the termination loads used for conductor-pair terminations in the balun-less setup.

Annex	What it covers
Annex A	Termination loads for termination of conductor pairs, including verification of the termination networks

What are the key requirements of oSIST prEN 3475-808:2026?

oSIST prEN 3475-808:2026 is built around controlled test setups, defined terminations, and reported results in dB. In practice, the document is about getting repeatable cross-talk measurements that can be compared against a product standard.

Cable type drives the test route

Clause 4.1 bases the coaxial-cable method on IEC 61196-1-122:2006, and the symmetrical-cable method on IEC 61156-1:2023 and IEC 61156-1-2:2023. That matters because the same cable family does not use the same setup.

Sample length and preparation matter

For symmetrical (balanced) cables, Clause 4.2.1 calls for a cable under test (CUT) length of at least 25 m unless otherwise stated. Ends must be prepared to minimize the influence of the connection to the test equipment, and the twisting of pairs or quads must be maintained. For equal level far-end cross-talk attenuation (ACR-F), the measured far-end cross-talk attenuation (FEXT) must sit far enough above the vector network analyser (VNA) noise floor to give a usable reading.

All relevant pair combinations are measured

Clause 4.2.2 requires all pair combinations for cables with more than two pairs. The standard allows measuring only one direction for each pair combination because both directions are treated as essentially equivalent. For a cable with N pairs, the number of combinations is N × (N - 1) / 2, which tells the test lab how many measurements are needed.

Two measurement routes are defined for balanced cables

Clause 4.2.3 describes a balun-based setup using a VNA, baluns, calibration artefacts, and resistor termination networks (RTN). The baluns must meet Class A requirements from EN 50289-1-1:2017. Clause 4.2.4 gives the balun-less route, which is preferred above 1 000 MHz and uses a four-port VNA with mixed-mode conversion.

Termination and calibration are controlled

Inactive pairs must be terminated with the correct differential-mode and common-mode reference impedances. Clause 4.2.3.1 gives different common-mode target levels depending on cable construction, and Annex A provides the termination network approach for the balun-less method. Calibration is performed on the secondary side of the baluns in the balun-based method, and as a full four-port single ended (SE) calibration in the balun-less method.

Results are reported as cross-talk metrics

Clause 4.2.5 defines near-end cross-talk (NEXT), power sum NEXT (PS NEXT), FEXT, ACR-F, and power sum ACR-F. The formulas tell the reader how to turn VNA measurements into the cross-talk figures used for acceptance and comparison.

Pass/fail depends on the product standard

Clause 5 says the cross-talk attenuation shall be within the limits given in the product standard for all pair combinations. In practice, this document gives the test method, while the cable-specific standard gives the acceptance limit.

What changed in oSIST prEN 3475-808:2026 from the previous edition?

oSIST prEN 3475-808:2026 supersedes EN 3475-808:2002. The main technical changes stated in the foreword are the introduction of vector network analysers to replace older generator-and-oscilloscope test arrangements, more detailed descriptions of the different cross-talk configurations, and the addition of balun-less measurement configurations.

Which standards are used with oSIST prEN 3475-808:2026?

oSIST prEN 3475-808:2026 refers to these documents for the test method and its supporting terminology:

• EN 50289-1-1:2017 - gives general requirements for electrical test methods and supports calibration and balun-related requirements.
• IEC 61196-1-122:2006 - provides the cross-talk test method for coaxial cables.
• IEC 61156-1:2023 - supports the method basis for symmetrical pair and quad cables.
• IEC 61156-1-2:2023 - supports the electrical transmission characteristics and test methods for symmetrical pair and quad cables.
• EN 3475-100 - listed in the bibliography as the general aerospace cable test-method reference for the series.

What does the oSIST prEN 3475-808:2026 document contain?

oSIST prEN 3475-808:2026 contains test setups for balun-based and balun-less measurement, including figures for near-end and far-end cross-talk arrangements. It also gives the formulas used to calculate NEXT, PS NEXT, FEXT, ACR-F, and PS ACR-F from VNA measurements.

Annex A contains the termination-load method for conductor pairs and a verification approach based on return loss measurement of the termination network. That annex is the practical guide for building and checking the resistor terminations used in the balun-less configuration, which is important for test repeatability and for lab qualification work.

SLOVENSKI STANDARD
01-oktober-2026
Nadomešča:
SIST EN 3475-808:2004
Aeronavtika - Električni kabli za uporabo v zračnih plovilih - Preskusne metode -
808. del: Presluh
Aerospace series - Cables, electrical, aircraft use - Test methods - Part 808: Cross-talk
Luft- und Raumfahrt – Elektrische Leitungen für Luftfahrt-Verwendung – Prüfverfahren–
Teil808: Nebensprechen
Série aérospatiale - Câbles électriques à usage aéronautique - Méthodes d'essais -
Partie 808 : Diaphonie
Ta slovenski standard je istoveten z: prEN 3475-808
ICS:
49.060 Letalska in vesoljska Aerospace electric
električna oprema in sistemi equipment and systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2026
ICS 49.060 Will supersede EN 3475-808:2002
English Version
Aerospace series - Cables, electrical, aircraft use - Test
methods - Part 808: Cross-talk
Série aérospatiale - Câbles électriques à usage Luft- und Raumfahrt - Elektrische Leitungen für
aéronautique - Méthodes d'essais - Partie 808 : Luftfahrt-Verwendung - Prüfverfahren- Teil808:
Diaphonie Nebensprechen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 3475-808:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Methods . 4
4.1 General. 4
4.2 Symmetrical (balanced) cables . 4
4.2.1 Test sample . 4
4.2.2 Pair combinations. 4
4.2.3 Balun based measurement . 5
4.2.4 Balun-less measurement . 8
4.2.5 Expression of test results . 11
4.3 Coaxial cables . 13
5 Requirement . 13
Annex A (normative) Termination loads for termination of conductor pairs . 14
Bibliography . 16

European foreword
This document (prEN 3475-808:2026) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 3475-808:2002.
EN 3475-808:2002:
— the use of vector network analysers has been introduced to replace outdated test configurations
using a generator and an oscilloscope. The different cross-talk configurations are described in
detail. Balun less measurement configurations are introduced.
1 Scope
This document specifies a method for measuring the cross-talk of a cable or between cables.
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.
EN 50289-1-1:2017, Communication cables — Specifications for test methods — Part 1-1: Electrical test
methods — General requirements
IEC 61196-1-122:2006, Coaxial communication cables — Part 1-122: Electrical test methods — Test for
cross-talk between coaxial cables
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
4 Methods
4.1 General
The test methods for the cross-talk between coaxial cables are based on IEC 61196-1-122:2006.
The test methods for the cross-talk of symmetrical (balanced) cables are based on IEC 61156-1:2023
and IEC 61156-1-2:2023.
4.2 Symmetrical (balanced) cables
4.2.1 Test sample
The cable under test (CUT) shall have a length of at least 25 m, if not stated otherwise. The maximum
cable length for the measurement of equal level far-end cross-talk (ACR-F) shall be such that the
measured far-end cross-talk attenuation (FEXT) is at least 10 dB less than the noise floor of the vector
network analyser (VNA), e.g. 80 db.
NOTE Equal level far-end cross-talk (ACR-F) was formerly denoted EL FEXT. The meaning of the acronym
ACR-F is attenuation to cross-talk ratio at far-end.
Both ends of the CUT shall be prepared, such that when connected to the terminals of the test
equipment the influence on the test result is minimized. The twisting of the pairs/quads shall be
maintained.
4.2.2 Pair combinations
In case of cables with more than two pairs (one quad) all pair combinations shall be measured. It is
admitted that measuring from pair A to pair B and pair B to pair A will essentially give the same results.
Therefore, in a cable with N pairs only N × (N-1) / 2 combinations may be measured. For example, in a
four pair cable, only six combinations may be measured: 1-2, 1-3, 1-4, 2-3, 2-4 and 3-4.
4.2.3 Balun based measurement
4.2.3.1 Test equipment
The test equipment shall be capable to measure the scattering parameters (as a complex quantity) of
the CUT in the frequency domain. A vector network analyser (VNA) having at least two ports and the
following is suitable:
— S-parameter set-up (shall be capable of performing measurements);
— baluns to convert the unbalanced signal of the VNA to a balanced signal. The baluns shall have an
impedance on the primary (unbalanced) side equal to the nominal impedance of the measuring
devices (in general 50 Ω) and on the secondary (balanced) side equal to the nominal impedance of
the cable under test (CUT) (e.g. 100 Ω). The baluns shall fulfil the requirements of Class A baluns as
described in EN 50289-1-1:2017;
— calibration artefacts to perform the required calibration of the test equipment on the secondary side
of the baluns. To perform a full two-port calibration a short circuit, an open circuit, a reference load,
and a short connection cable or similar, are required. The short circuit shall have negligible
inductance and the open circuit shall have negligible capacitance. The load resistor shall have a
value close (within 1 %) to the nominal impedance of the CUT (e.g. 100 Ω) and with negligible
inductance and capacitance. The connection cable shall be as short as possible and well matched to
the nominal impedance;
— resistor termination networks (RTN) for termination of inactive pairs. The resistor termination
network shall provide the differential mode and the common mode reference termination
impedances. For cables having a nominal (differential) impedance (Z ) of 100, the common-mode
diff
impedance (Z ) is:
com
• about 75 Ω for up to twenty-5 pair-count unscreened pair cables;
• about 50 Ω for common screened pair cables and more than twenty-5 pair-count unscreened
pair cables;
• about 25 Ω for individually screened pair cables.
In principle in balun measurements, the test shall be carried out with the condition that differential
mode impedance (Z ) and common mode impedance (Z ) of test specimen is matched by the balun
diff com
and the vector network analyser (or equivalent instruments) respectively.
But in practice, as the vector network analyser (or equivalent instrument) used in the measurement has
50 Ω ports in general and the common mode impedance of the balun is also 50 Ω, the common mode
impedance of the test specimen shall be assumed 50 Ω unless otherwise specified. This is to simplify
measurements when the common mode impedance of test specimen vary from 25 Ω to 75 Ω,
see Figure 1. Baluns may be used for termination of the inactive pairs if they provide the specified
differential and common mode terminations.
Key
Z is differential-mode termination resistor (Ω);
dm
Z is common-mode termination resistor (Ω);
cm
Z is differential-mode impedance of cable (Ω);
diff
Z is common-mode impedance of cable (Ω).
com
Figure 1 — Resistor terminations in balun measurements
4.2.3.2 Calibration procedure
It is not the intent of the standard to detail the algorithms applied by a VNA to correct the measured
results based on a calibration procedure, but to detail the calibration procedure. Further information
can be obtained in the manuals of the VNA supplier.
The calibration shall be performed on the secondary side of the baluns. A full two-port calibration is
recommended using open, short, and load calibration artefacts at the terminals of the balun, and a short
connection cable between the two baluns for the through calibration.
4.2.3.3 Measurement procedure for near-end cross-talk
The cable under test (CUT) shall be connected to the terminals of the test equipment as depicted in
Figure 2, including proper termination of the active pairs, the inactive pairs, and the screen.
The connection of the CUT to the test ports shall be optimized, such that the mismatch at the connection
is minimized.
One end of the pairs under test shall be connected to baluns, the other end shall be connected to ground
through appropriate common-mode and differential-mode terminations (see 4.2.3.1).
All pairs not under test shall be connected to ground through appropriate common-mode and
differential-mode terminations at the near and far end (see 4.2.3.1).
The screens, if any, shall be connected to ground at both ends of the cable. Precautions shall be taken to
minimize end effect couplings. When the cable sheath is removed, the pairs shall maintain their twist
and shall be well separated.
Measure the forward transmission scattering parameter differential mode, S .
dd21
Key
CUT cable under test
VNA/G network analyser port or generator
VNA/R network analyser port or receiver
* common-mode termination resistor
** differential-mode termination resistor (matched in pairs)
L length of cable under test (m)
Figure 2 — Balun based test set-up for near-end cross-talk
4.2.3.4 Measurement pr
...