Twinax cables for digital communications - Part 1: Generic specification

IEC 62783-1:2023 specifies definitions, requirements and test methods of twinax cables used in digital communication systems: computer rooms, data centres, servers, etc. These cables are intended to be used indoors.
This document details the requirements and transmission characteristics for single twinax elements as well as multiple twinax elements within the same sheath, i.e. “twinax cable”. IEC 62783-1 ED2 is applicable to twinax cables and also twinax cable assemblies. This document is supplemented with family specifications that give additional requirements based on the specific application, for example, the minimum and maximum specified frequency of the cables.

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IEC 62783-1 ®
Edition 2.0 2023-05
Twinax cables for digital communications –
Part 1: Generic specification
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IEC 62783-1 ®
Edition 2.0 2023-05
Twinax cables for digital communications –

Part 1: Generic specification
ICS 33.120.20 ISBN 978-2-8322-7002-8

– 2 – IEC 62783-1:2023 © IEC 2023
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 9
4 Materials and cable construction . 9
4.1 General remarks . 9
4.2 Cable construction . 10
4.2.1 General . 10
4.2.2 Conductor . 10
4.2.3 Insulation . 10
4.2.4 Cable element . 10
4.2.5 Cable make-up . 11
4.2.6 Screening of the cable core . 11
4.2.7 Sheath . 12
4.2.8 Identification . 12
4.2.9 Finished cable . 12
5 Requirements and test methods . 13
5.1 General requirements . 13
5.2 Electrical characteristics and tests . 13
5.2.1 General . 13
5.2.2 Conductor resistance . 13
5.2.3 Resistance unbalance. 13
5.2.4 Dielectric strength . 13
5.2.5 Insulation resistance . 13
5.2.6 Surface transfer impedance . 14
5.2.7 Coupling attenuation . 14
5.3 Transmission characteristics and tests . 14
5.3.1 General . 14
5.3.2 Length . 14
5.3.3 Characteristic impedance . 15
5.3.4 Return loss . 15
5.3.5 Attenuation . 15
5.3.6 Propagation delay, inter-pair skew, and intra-pair skew . 16
5.3.7 Near-end crosstalk (NEXT) . 16
5.3.8 Differential mode to common mode conversion (Scd21) . 17
5.3.9 Equal level transverse conversion transfer loss (Scd21-Sdd21) . 17
5.4 Mechanical and dimensional requirements and test methods . 17
5.4.1 General . 17
5.4.2 Measurement of dimensions . 17
5.4.3 Elongation at break of the conductor. 17
5.4.4 Tensile strength of the insulation . 17
5.4.5 Elongation at break of the sheath . 18
5.4.6 Tensile strength of the sheath . 18
5.4.7 Crush test of the cable . 18
5.4.8 Cold impact test of the cable . 18

5.4.9 Repeated bending of the cable . 18
5.4.10 Tensile performance of the cable . 18
5.4.11 Vibration test of the cable . 18
5.5 Environmental tests . 18
5.5.1 Shrinkage of the insulation . 18
5.5.2 Wrapping test of the insulation after thermal ageing . 18
5.5.3 Bending test of the insulation at low temperature . 18
5.5.4 Tensile strength and elongation of the sheath after ageing . 18
5.5.5 Sheath pressure test at high temperature . 18
5.5.6 Cold bend test of the cable . 19
5.5.7 Heat shock test . 19
5.5.8 Damp heat steady state . 19
5.5.9 Salt mist . 19
5.5.10 Flame propagation characteristics of a single cable . 19
5.5.11 Flame propagation characteristics of bunched cables . 19
5.5.12 Halogen-free compounds test . 19
5.5.13 Smoke generation . 19
5.5.14 Combined flame and smoke test for cables in environmental air
handling spaces . 19
Bibliography . 20

– 4 – IEC 62783-1:2023 © IEC 2023

Part 1: Generic specification
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IEC 62783-1 has been prepared by subcommittee 46C: Wires and symmetric cables, of IEC
technical committee 46: Cables, wires, waveguides, RF connectors, RF and microwave passive
components and accessories. It is an International Standard.
This second edition cancels and replaces the first edition published in 2019. This edition
constitutes a technical revision.
This edition includes the following significant technical changes compared with the previous
– 4.1: single

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