ISO 19642-1:2023

INTERNATIONAL ISO
STANDARD 19642-1
Second edition
2023-08
Road vehicles — Automotive cables —
Part 1:
Vocabulary and design guidelines
Véhicules routiers — Câbles automobiles —
Partie 1: Vocabulaire et lignes directrices pour la conception
Reference number
ISO 19642-1:2023(E)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO 19642-1:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 19642-1:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms related to voltage rating . 1
3.2 Terms related to temperatures . 2
3.3 Terms related to cables . 2
3.4 Terms related to RF systems and properties . 10
Annex A (informative) Design guidelines for calculation of dimensions in multi-core cables .15
Annex B (informative) Recommended colour concentrations .23
Annex C (informative) Expert opinion on re-testing of existing cables .24
Bibliography .27
iii
© ISO 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO 19642-1:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic components and general system aspects.
This second edition cancels and replaces the first edition (ISO 19642-1:2019), which has been technically
revised.
The main changes are as follows:
— new parts have been added to the ISO 19642 series (ISO 19642-11 and ISO 19642-12);
— reflecting these additions ISO 19642-2 had to be amended;
— some new terms and definitions for screened RF cables have been added for a new standard of the
ISO 19642 series;
— Annex C has been added to give informative advice on how to address and manage requalification
of cables already released against the older ISO standards ISO 6722-1 and ISO 6722-2.
A list of all parts in the ISO 19642 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
 © ISO 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 19642-1:2023(E)
Introduction
This document was prepared following a joint resolution to improve the general structure of the ISO
automotive electric cable standards. This new structure adds more clarity and, by defining a new
standard family, opens up the standard for future amendments.
Many other standards currently refer to ISO 6722-1, ISO 6722-2 and ISO 14572. These standards will
stay valid at least until the next scheduled systematic review and will be replaced later by the ISO 19642
series.
For new automotive cable projects, customers and suppliers are advised to use the ISO 19642 series.
This document defines general terms used in cable engineering to lay a solid foundation for discussions
and written information transfer in this field.
Annex A informally defines a calculation method for many important cable parameters (e.g. resistance
limits, several cable dimension).
Annex B informally proposes preferred colour concentrations for automotive cables.
Annex C gives an expert opinion on how to address and manage requalification of single core cables
already released against the old, but still active, ISO standards ISO 6722-1 and ISO 6722-2.
v
© ISO 2023 – All rights reserved

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 19642-1:2023(E)
Road vehicles — Automotive cables —
Part 1:
Vocabulary and design guidelines
1 Scope
This document defines terms in the field of cables applied in road vehicle general purpose applications,
for use in the other parts of the ISO 19642 series.
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.
ISO 19642-7, Road vehicles — Automotive cables — Part 7: Dimensions and requirements for 30 V a.c. or 60
V d.c. round, sheathed, screened or unscreened multi or single core copper conductor cables
ISO 19642-8, Road vehicles — Automotive cables — Part 8: Dimensions and requirements for 30 V a.c. or 60
V d.c. round, sheathed, screened or unscreened multi or single core aluminium conductor cables
3 Terms and definitions
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/
3.1 Terms related to voltage rating
3.1.1
AC voltage
voltage in an alternating current circuit that also periodically reverses because the current has a
periodic function of time
Note 1 to entry: Whenever AC voltage is specified in the ISO 19642 series, the AC root mean square (r.m.s.) value
shall be used.
3.1.2
60 V cable
cable (3.3.7) intended for use in road vehicle applications where the nominal system voltage (3.1.6) is
less than or equal to 30 V a.c. or 60 V d.c.
3.1.3
900 V cable
cable (3.3.7) intended for use in road vehicle applications where the nominal system voltage (3.1.6) is
less than or equal to 600 V a.c. or 900 V d.c.
1
© ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 19642-1:2023(E)
3.1.4
1 500 V cable
cable (3.3.7) intended for use in road vehicle applications where the nominal system voltage (3.1.6) is
less than or equal to 1 000 V a.c. or 1 500 V d.c.
3.1.5
DC voltage
non-alternating constant or pulsed voltage
3.1.6
nominal system voltage
maximum continuous voltage of a conductor (3.3.13) to its system ground under normal conditions
3.2 Terms related to temperatures
3.2.1
temperature class rating
temperature range for safe operation of the cable (3.3.7) divided into eight temperature classes as
defined in Table 1
Table 1 — Temperature class rating
Temperature
Class Is equivalent to Class
°C
A T 1 −40 to 85
B T 2 −40 to 100
C T 3 −40 to 125
D T 4 −40 to 150
E T 5 −40 to 175
F T 6 −40 to 200
G T 7 −40 to 225
H T 8 −40 to 250
3.2.2
room temperature
RT
situation with a temperature of (23 ± 3) °C and a relative humidity (RH) of 45 % to 75 %
3.3 Terms related to cables
3.3.1
bare conductor
metal cable (3.3.7) conductor (3.3.13) in which the strand or strands are not coated
3.3.2
bedding layer
non-metallic covering applied (normally extruded) around the assembly of the cores (3.3.14) (and fillers
(3.3.18), if any) of a multi-core cable (3.3.29) to obtain a more circular outline
3.3.3
braid
covering formed from bare or plated metallic or non-metallic material
3.3.4
braid parameter
parameter of a braid (3.3.3) as defined in Table 2
2
 © ISO 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 19642-1:2023(E)
Table 2 — Braid parameter formulae
Diameter Number of single strands in one Angle of lay perpendicular
over braid direction to cable axis
2×L
n
L
C
θ =arctan
DD=+4× D
nn=×
BC S
dS
π×+()DD
2
BC
Optical coverage,
2)
Coverage Lay length
braid percentage
nD×
dS
B = B<1
n
S
L ×cos()θ
BB=×()2 − B² ×100
L L =×25,4
o
L
2×P
11B≥
Key to braid parameters
D diameter of single strand, in mm
S
D diameter of core below the braid, in mm
C
D diameter over braid, in mm
B
n number of strands in one carrier
S
n number of single strands in one direction
d
n number of carriers
c
L lay length, in mm
L
θ angle of lay perpendicular to cable axis, in degrees
P picks per inch (number of braid crossover points in 1” = 25,4 mm)
B coverage, proportion of the covered surface by strands in one direction compared to the whole surface
B optical coverage, also called braid percentage; proportion of the covered surface by strands in both directions
o
compared to the whole surface, in percentage
Note 1 to entry: For better accuracy the angle θ shall not be measured directly but be calculated from the
measured dimensional parameters referenced in the formulae above.
Note 2 to entry: A value of B > 1 is physically impossible so, if due to measurement tolerances, a value of B > 1 is
obtained, it shall be adjusted to 1.
Note 3 to entry: A braid is formed by a number of single strands which are grouped into carriers and applied to
the cable (3.3.7) surface in two different directions (left and right or S and Z) in a form that each carrier of one
direction is alternatively above and below the adjacent carrier of the other direction.
Note 4 to entry: See Figure 1.
Figure 1 — Angle of lay
3
© ISO 2023 – All rights reserved

---------------------- Page: 8 ----------------------
ISO 19642-1:2023(E)
3.3.5
bunched conductor
conductor (3.3.13) in which individual strands are assembled together in helical formation, all in the
same direction and with the same length of lay
3.3.6
bunching loss
F
x,b
ratio of conductor (3.3.13) resistance before and after the bunching process of stranded conductors
(3.3.36)
Note 1 to entry: The factor, F , is derived by the formula:
x,b
mR ·· κ
mean mean
F =
x,b
1 000 · ρ
where
2
κ is the conductivity of the used conductor material in Sm/mm ;
3
ρ is the density of the conductor material in kg/dm = kg/l;
m is the mean of measured conductor mass in g/m;
mean
R is the mean of measured conductor resistance at 20 °C in mΩ/m.
mean
3.3.7
cable
single or multi-core wire (3.3.39)
Note 1 to entry: Cable dimension definitions are shown in Figure 2.
3.3.8
cable family
group with multiple conductor (3.3.13) sizes having the same conductor, strand coating, insulation
(3.3.23) formulation, and wall thickness type
3.3.9
cable dimension
property of a cable (3.3.7) with physical unit (mm)
Note 1 to entry: Cable dimension definitions are shown in Figure 2.
4
 © ISO 2023 – All rights reserved

---------------------- Page: 9 ----------------------
ISO 19642-1:2023(E)
Key
a conductor (3.3.13) diameter 2 core insulation (3.3.23)
b core (3.3.14) diameter 3 inner covering (3.3.22)
c twisted core diameter 4 filler (3.3.18)
d diameter under sheath 5 drain wire (3.3.17)
e outside cable diameter 6 foil
f wall thickness sheath 7 screen (3.3.32)
1 conductor 8 sheath (3.3.34)
Figure 2 — Cable dimension definitions
3.3.10
coaxial cable
cable (3.3.7) with one single inner conductor (3.3.13), an insulation (3.3.23) also called dielectric (3.3.16),
a concentric cylindrical screen (3.3.32) as an outer conductor and a sheath (3.3.34)
5
© ISO 2023 – All rights reserved

---------------------- Page: 10 ----------------------
ISO 19642-1:2023(E)
3.3.11
colour code
code of a cable (3.3.7) colour to make it visually distinguishable from the others
Note 1 to entry: The recommended colours are listed in Table 3.
Note 2 to entry: Annex B indicates recommended colour concentrations for the colours listed in Table 3.
Table 3 — Recommended colours and colour codes
Colour Colour code
Black BK
Blue BU
Brown BN
Green GN
Orange OG
Red RD
Violet (purple) VT
White WH
Yellow YE
NOTE Other colours can be used based on agreement between customer and supplier (see IEC 60757).
3.3.12
compressed conductor
stranded conductor (3.3.36) in which the interstices between the strands have been reduced by
mechanical compression into a circular shape with reduced outside diameter
Note 1 to entry: See Figure 3.
a) Compressed conductor b) Compressed conductor with insulation
(3.3.23) only
Figure 3 — Compressed conductor
3.3.13
conductor
one or multitude of bare, coated or cladded electrically conductive strands
3.3.14
core
insulated conductor (3.3.13) assembly comprising a conductor with its own insulation (3.3.23) (and
screens (3.3.32), if any)
6
  © ISO 2023 – All rights reserved

---------------------- Page: 11 ----------------------
ISO 19642-1:2023(E)
3.3.15
cross-sectional area
CSA
calculated or measured area of the conductor (3.3.13)
3.3.16
dielectric
insulation (3.3.23) of the inner core (3.3.14) of a coaxial cable (3.3.10)
3.3.17
drain wire
uninsulated or conductive coated conductor (3.3.13) laid in contact with a screen (3.3.32) or a shield
(3.3.32)
3.3.18
filler
component used to fill the interstices between the cores (3.3.14) or fill a void for roundness of a multi-
core cable (3.3.29)
3.3.19
flexibility
property of a cable (3.3.7) that allows for bending under the influence of an outside force
3.3.20
flex life
property of a cable (3.3.7) to withstand repeated bending
3.3.21
general purpose cable
cable (3.3.7) meeting basic requirements for standard automotive applications
3.3.22
inner covering
non-metallic covering which surrounds the assembly of the cores (3.3.14) (and fillers (3.3.18), if any) of a
multi-core cable (3.3.29) and over which the protective covering is applied
3.3.23
insulation
set of insulating materials incorporated on a conductor (3.3.13) or screen (3.3.32) with a specific
function of insulating and/or protecting the conductive elements
3.3.24
ISO conductor size
nominal value (3.3.30) / denomination of the ISO wire (3.3.39) used as a reference in this document
3.3.25
lay direction
direction of rotation of a component of a cable (3.3.7) in relation to the longitudinal axis of the cable
(3.3.7)
Note 1 to entry: The lay is said to be right-hand when the visible portion of the helix, together with the two cross-
sections limiting it, form the shape of a letter Z, and left-hand when they form the shape of a letter S. See Figure 4.
7
© ISO 2023 – All rights reserved

---------------------- Page: 12 ----------------------
ISO 19642-1:2023(E)
a) Right-hand b) Left-hand
Figure 4 — Lay direction
3.3.26
lay length
axial length of one complete rotation of the helix formed by one cable (3.3.7) component, for example an
individual strand or core (3.3.14)
Note 1 to entry: See Figure 5.
Key
L length where a core in the outermost layer of the bunching/twisting fulfils a full 360° turn
L
Figure 5 — Lay length
3.3.27
metal-coated conductor

3.3.27.1
cladded conductor
conductor (3.3.13) in which each individual strand is bonded with a thin layer of another different metal
or metal alloy
3.3.27.2
plated conductor
conductor (3.3.13) in which each individual strand is electroplated with a thin layer of another different
metal or metal alloy
3.3.28
percentage of International Annealed Copper Standard
percentage of the volume resistivity of a metal when compared to 100 % of pure annealed copper
2
having a volume resistivity of 0,017 24 Ω × mm /m at 20 °C as defined in IEC 60028
8
  © ISO 2023 – All rights reserved

---------------------- Page: 13 ----------------------
ISO 19642-1:2023(E)
3.3.29
multi-core cable
cable (3.3.7) having more than one core (3.3.14), some of which can be un-insulated (e.g. drain wire
(3.3.17))
Note 1 to entry: See Figure 6.
Note 2 to entry: Annex A provides design guidelines for calculating dimensions in multi-core cables.
Figure 6 — Multi-core cable with screen and sheath
3.3.30
nominal value
suitable approximate value used to designate or identify an attribute of a component
3.3.31
rope-stranded conductor
stranded conductor (3.3.36) consisting of a number of groups of strands assembled together in one or
more helical layers, the wires (3.3.39) in each group being either bunched or stranded
Note 1 to entry: See examples in Figure 7.
Figure 7 — Rope-stranded conductors
3.3.32
screen
shield
conductive material intended to reduce the penetration and/or radiation of a varying electromagnetic
field
Note 1 to entry: Metallic sheaths (3.3.35), foils, braids (3.3.3), armours and earthed concentric conductors (3.3.13)
may also serve as shields.
9
© ISO 2023 – All rights reserved

---------------------- Page: 14 ----------------------
ISO 19642-1:2023(E)
3.3.33
separator
thin layer used to facilitate the separation of, or as a barrier to prevent mutually detrimental effects
between different components of a cable (3.3.7), such as between the conductor (3.3.13) and the
insulation (3.3.23) or between the insulation and the sheath (3.3.34)
3.3.34
sheath
jacket
non-conductive, uniform and continuous covering of material, generally extruded
3.3.35
special purpose cable
cable (3.3.7) meeting basic requirements plus additional or enhanced performance requirements for
unique applications
Note 1 to entry: Unique requirements are as defined by the customer.
3.3.36
stranded conductor
conductor (3.3.13) consisting of a number of individual strands, all or some of which are wound in a
helix
3.3.37
strip force
force needed to remove or displace an outer layer of a cable (3.3.7) from the subjacent cable elements
Note 1 to entry: For a single inner conductor coaxial cable (3.3.10) three different strip forces and the
corresponding test procedures are defined in ISO 19642-2.
Note 2 to entry: The following strip forces are defined:
Strip force a) between inner conductor and dielectric cable insulation;
Strip force b) between dielectric cable core and the screen together with the sheath (screen + sheath
 composite);
Strip force c) between screen and sheath.
3.3.38
twisting loss
ratio of conductor (3.3.13) resistance before and after the twisting process of cores (3.3.14)
3.3.39
wire
stranded or solid cylindrical conductor (3.3.13), with or without an insulating covering
3.4 Terms related to RF systems and properties
3.4.1
100BASE-T1 Ethernet
standardized in IEEE 8802.3, physical layer which applies to a single balanced twisted pair cable
capable of transmitting 100 Mbit/s up to 15 m in total length
3.4.2
1000BASE-T1 Ethernet
standardized in IEEE 8802.3, physical layer which applies to a single balanced twisted pair cable
capable of transmitting 1 000 Mbit/s up to 15 m (segment A) or 40 m (segment B) in total length
10
  © ISO 2023 – All rights reserved

---------------------- Page: 15 ----------------------
ISO 19642-1:2023(E)
3.4.3
alien crosstalk
exogenous crosstalk
unwanted disturbing signal, stated in dB, coupling from one balanced pair cable to another
3.4.4
balanced cable
data transmission cable consisting of two cores (3.3.14) which have uniform differential impedance
(3.4.17) along their length
Note 1 to entry: Common forms of balanced cables are twisted pair, parallel pair and twin lead cables.
3.4.5
bus capacitance
C
bus
capacitive load of differential data cores in multi-core cables (3.3.29) stated in pF/m
3.4.6
capacitance
C
ability to store electric charge between conductors (3.3.13) or conductor to ground, measured in pF/m
3.4.7
controller area network
CAN
serial data communication protocol
Note 1 to entry: See the ISO 11898 series.
3.4.8
CAN-FD
flexible data rate
extension to CAN (3.4.7) that is able to transmit data at a higher rate
3.4.9
characteristic impedance
ratio of the electric [V/m] and magnetic field [A/m] strengths of a single wave, the physical unit is (Ω)
Note 1 to entry: See Table 4 for a list of characteristic impedance modes:
Table 4 — Characteristic impedance modes
CICMF characteristic impedance common mode frequency domain
CICMT characteristic impedance common mode time domain
CIDMF characteristic impedance differential mode frequency domain
CIDMT characteristic impedance differential mode time domain
3.4.10
common mode
CM
mode of transmission where the signal is propagated in reference to the ground level
3.4.11
crosstalk
phenomenon of the unwanted signal transmitted from one aggressor circuit or channel of a transmission
system to the victim circuit or channel (for two or more channels in the same bundle)
11
© ISO 2023 – All rights reserved

---------------------- Page: 16 ----------------------
ISO 19642-1:2023(E)
3.4.11.1
far-end crosstalk
FEXT
level of interference that occurs between one pair and another within the same cable (3.3.7) measured
at the far end of the cable, stated in dB
3.4.11.2
near-end crosstalk
NEXT
level of interference that occurs between one pair and another within the same cable (3.3.7) measured
at the near end of the cable, stated in dB
3.4.11.3
alien near-end crosstalk
ANEXT
level of interference that occurs between one pair of a cable (3.3.7) and an exogenous source measured
at the near end of the cable, stated in dB
3.4.11.4
powersum attenuation to alien crosstalk ratio
PS-AACR-F
ANEXT ratio of the sum of the total power coupled to a wire (3.3.39) pair from exogenous sources
measured at the far-end minus the insertion loss (3.4.18) compared to the input power, stated in dB
3.4.12
de-embedding
mathematical method to remove the influence of connector and connecting hardware properties from
frequency domain (F) (3.4.15) cable measurement data
3.4.13
differential mode
DM
mode of transmission where the signal is propagated symmetrically to the reference voltage
3.4.14
FlexRay
automotive network communications protocol
Note 1 to entry: See the ISO 17458 series.
3.4.15
frequency domain
F
representation of a signal with respect to variable frequencies
3.4.16
gating
mathematical method to remove the influence of connector and connecting hardware properties from
time domain (T) (3.4.26) cable measurement data
3.4.17
impedance
Z
ratio of the voltage between the conductors (3.3.13) and the current in the conductors, described as a
complex number
12
  © ISO 2023 – All rights reserved

---------------------- Page: 17 ----------------------
ISO 19642-1:2023(E)
3.4.18
insertion loss
IL
attenuation
loss of signal power resulting in a transmission line and is stated in dB/m
Note 1 to entry: For unbalanced systems IL can be calculated from S-parameters S or S , for balanced systems
21 12
IL can be calculated from S-parameters S or S .
dd21 dd12
3.4.19
in-pair skew
intra-pair skew
difference of propagation delay (3.4.23) between the two primary wires (3.3.39) of a single pair
3.4.20
inter-pair skew
difference of propagation delay (3.4.23) between two pairs
3.4.21
JUTP
acronym for jacketed (sheathed) un-shielded twisted pair cable
3.4.22
mutual capacitance
capacitance (3.4.6) between two insulated wires (3.3.39) in a twisted pair, stated in (pF/m)
3.4.23
propagation delay
amount of time it takes for the head of a signal to travel from the sender to the receiver
3.4.24
resistance unbalance
difference in DC resistance between two conductors (3.3.13), usually in a twisted pair
3.4.25
return loss
RL
ratio stated in decibels (dB) of the power of the outgoing signal to the power of the reflected or returned
signal
Note 1 to entry: For unbalanced systems this is defined as S-parameter S or S , for balanced system S or
11 22 dd11
S .
dd22
3.4.26
time domain
representation of a signal with respect to a variable time
3.4.27
unbalance attenuation
combinations of common mode (3.4.10) versus differential mode (3.4.13) measurements
Note 1 to entry: For definitions of possible combinations see Table 5 and IEC TR 61156-1-2.
13
© ISO 2023 – All rights reserved

---------------------- Page: 18 ----------------------
ISO 19642-1:2023(E)
Table 5 — Unbalance measurement modes
Related
Definition S -parame- Measured output Stimulus input
ter
Acronym Name Mode End Mode End
c 1 d 1
TCL transverse conversion loss S
cd11
common near differential near
d 1 c 1
LCL longitudinal conversion loss S
dc11
differential near common near
transverse conversion c 2 1
TCTL S d differential
cd21
transfer loss common far near
equal level transverse conver- c 2 1
a
EL TCTL S d differential
cd21
sion transfer loss common far near
longitudinal conversion trans- d 2 c 1
LCTL S
dc21
fer loss differential far common near
equal level longitudinal conver- d 2 c 1
b
EL LCTL S
dc21
sion transfer loss differential far common near
a
It is the same as TCTL but attenuation (3.4.18) is taken into account in the power ratio calculation.
b
It is the same as LCTL but attenuation is taken into account in the power ratio calculation.
3.4.28
unbalanced cable
cable (3.3.7), often a coaxial cable (3.3.10), where the signal is transmitted in common mode (3.4.10)
3.4.29
UTP
acronym for unshielded twisted pair cable without jacket (3.3.34)
3.4.30
velocity of propagation
speed of a wave along a transmission line stated as a percentage of the speed of light
14
  © ISO 2023 – All rights reserved

---------------------- Page: 19 ----------------------
ISO 19642-1:2023(E)
Annex A
(informative)

Design guidelines for calculation of dimensions in multi-core
cables
A.1 General
Due to geometric principles and the effect of subsequent production processes like twisting, braiding
and sheath extrusion, the properties of the single cores in a multi-core cable are changed.
This annex provides guidelines on how these effects can be calculated.
It also gives guidelines on how to calculate the wall thicknesses of sheath and bedding layers and which
tolerances should be guaranteed.
A.2 Outside diameter of twisted cores
The maximum outside diameter of twisted cores, D , is calculated using the stranding factors in
t,max
Table A.1.
For certain numbers of cores (for example 5 or 6), filler cores may be used to get a stable bunching/
twisting. The outside diameter of the twisted cores and the diameter of filler cores are calculated
according to the following formulae:
D = F × D
t,max
...