EN IEC 61280-4-2:2024

SLOVENSKI STANDARD
01-september-2024
Postopki za preskušanje optičnih komunikacijskih podsistemov - 4-2. del:
Kabelska inštalacija - Meritve slabljenja v enorodovnih vlaknih in optičnih
povratnih izgub (IEC 61280-4-2:2024)
Fibre-optic communication subsystem test procedures - Part 4-2: Installed cabling plant -
Single-mode attenuation and optical return loss measurements (IEC 61280-4-2:2024)
Prüfverfahren für Lichtwellenleiter-Kommunikationsuntersysteme - Teil 4-2: Installierte
Kabelanlagen - Einmoden-Dämpfungs- und optische Rückflussdämpfungsmessung (IEC
61280-4-2:2024)
Procédures d’essai des sous-systèmes de télécommunication fibroniques - Partie 4-2:
Installations câblées - Mesure de l'affaiblissement de réflexion optique et de
l'affaiblissement des fibres unimodales (IEC 61280-4-2:2024)
Ta slovenski standard je istoveten z: EN IEC 61280-4-2:2024
ICS:
33.180.01 Sistemi z optičnimi vlakni na Fibre optic systems in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61280-4-2

NORME EUROPÉENNE
EUROPÄISCHE NORM June 2024
ICS 33.180.01 Supersedes EN 61280-4-2:2014
English Version
Fibre-optic communication subsystem test procedures - Part 4-2:
Installed cabling plant - Single-mode attenuation and optical
return loss measurements
(IEC 61280-4-2:2024)
Procédures d'essai des sous-systèmes de Prüfverfahren für Lichtwellenleiter-
télécommunication fibroniques - Partie 4-2: Installations Kommunikationsuntersysteme - Teil 4-2: Installierte
câblées - Mesures de l'affaiblissement de réflexion optique Kabelanlagen - Einmoden-Dämpfungs- und optische
et de l'affaiblissement des fibres unimodales Rückflussdämpfungsmessung
(IEC 61280-4-2:2024) (IEC 61280-4-2:2024)
This European Standard was approved by CENELEC on 2024-06-10. CENELEC 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.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61280-4-2:2024 E

European foreword
The text of document 86C/1912/FDIS, future edition 3 of IEC 61280-4-2, prepared by SC 86C "Fibre
optic systems and active devices" of IEC/TC 86 "Fibre optics" was submitted to the IEC-CENELEC
parallel vote and approved by CENELEC as EN IEC 61280-4-2:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-03-10
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-06-10
document have to be withdrawn
This document supersedes EN 61280-4-2:2014 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61280-4-2:2024 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60793-1-40 NOTE Approved as EN IEC 60793-1-40
IEC 60793-2 NOTE Approved as EN IEC 60793-2
IEC 60793-2-50 NOTE Approved as EN IEC 60793-2-50
IEC 61280-1-3 NOTE Approved as EN IEC 61280-1-3
IEC 61280-4-3:2022 NOTE Approved as EN IEC 61280-4-3:2022 (not modified)
IEC 61280-4-5 NOTE Approved as EN IEC 61280-4-5
IEC 61300-3-4 NOTE Approved as EN IEC 61300-3-4
IEC 61300-3-6 NOTE Approved as EN 61300-3-6
IEC 61745 NOTE Approved as EN 61745
IEC 61753-1 NOTE Approved as EN IEC 61753-1
IEC 61754-19 NOTE Approved as EN 61754-19
IEC 61755-1 NOTE Approved as EN IEC 61755-1
IEC 61755-2-1 NOTE Approved as EN IEC 61755-2-1
IEC 61755-2-2 NOTE Approved as EN IEC 61755-2-2
IEC 61755-2-4 NOTE Approved as EN 61755-2-4
IEC 61755-2-5 NOTE Approved as EN 61755-2-5
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60825-2 - Safety of laser products - Part 2: Safety of - -
optical fibre communication systems
(OFCSs)
IEC 61300-3-35 - Fibre optic interconnecting devices and EN IEC 61300-3-35 -
passive components - Basic test and
measurement procedures - Part 3-35:
Examinations and measurements - Visual
inspection of fibre optic connectors and
fibre-stub transceivers
IEC 61315 - Calibration of fibre-optic power meters EN IEC 61315 -
IEC 61746-1 2009 Calibration of optical time-domain EN 61746-1 2011
reflectometers (OTDR) - Part 1: OTDR for
single mode fibres
- - + AC 2014
IEC/TR 62627-01 - Fibre optic interconnecting devices and - -
passive components - Part 01: Fibre optic
connector cleaning methods
IEC 61280-4-2 ®
Edition 3.0 2024-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fibre- optic communication subsystem test procedures –

Part 4-2: Installed cabling plant – Single-mode attenuation and optical return

loss measurements
Procédures d’essai des sous-systèmes de télécommunication fibroniques –

Partie 4-2: Installations câblées – Mesures de l'affaiblissement de réflexion

optique et de l'affaiblissement des fibres unimodales

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.01  ISBN 978-2-8322-8789-7

– 2 – IEC 61280-4-2:2024 © IEC 2024
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 11
3 Terms, definitions, graphical symbols and abbreviated terms. 12
3.1 Terms and definitions . 12
3.2 Graphical symbols . 14
3.3 Abbreviated terms . 16
4 Measurement methods . 16
4.1 General . 16
4.1.1 Document structure . 16
4.1.2 Attenuation . 17
4.1.3 Optical return loss . 17
4.2 Cabling configurations and applicable test methods . 18
4.2.1 Cabling configurations and applicable test methods for attenuation
measurements . 18
4.2.2 Cabling configurations and applicable test methods for optical return
loss measurements . 22
5 Overview of uncertainties for attenuation measurements . 22
5.1 General . 22
5.2 Sources of significant uncertainties . 22
5.3 Consideration of the power meter . 22
5.4 Consideration of test cord and connector grade . 23
5.4.1 General . 23
5.4.2 Mode field diameter variation . 23
5.5 Reflections from other interfaces. 23
5.6 Optical source . 24
5.7 Output power reference . 24
5.8 Bi-directional measurements . 24
5.9 Typical uncertainties for attenuation methods A, B, C, and D . 24
5.10 Typical uncertainty values for single-mode attenuation testing for method E . 26
6 Apparatus . 26
6.1 General . 26
6.2 Light source . 26
6.2.1 Stability . 26
6.2.2 Spectral characteristics . 27
6.3 Launch cord . 28
6.4 Receive or tail cords . 28
6.5 Substitution cord . 28
6.6 Power meter – LSPM methods only. 28
6.7 OTDR apparatus . 29
6.8 Return loss test set . 29
6.9 Connector end-face cleaning and inspection equipment . 30
6.10 Adapters . 30
7 Procedures . 31
7.1 General . 31
7.2 Common procedures . 31

IEC 61280-4-2:2024 © IEC 2024 – 3 –
7.2.1 Care of the test cords . 31
7.2.2 Make reference measurements (LSPM and OCWR methods only) . 31
7.2.3 Inspect and clean the ends of the fibres in the cabling . 31
7.2.4 Make the measurements . 32
7.2.5 Make the calculations . 32
7.3 Calibration . 32
7.4 Safety . 32
8 Calculations . 32
9 Documentation . 32
9.1 Information for each test . 32
9.2 Information to be made available . 33
Annex A (normative) One-cord reference method . 34
A.1 Applicability of test method . 34
A.2 Apparatus . 34
A.3 Procedure . 34
A.4 Calculation . 35
A.5 Components of reported attenuation . 36
Annex B (normative) Three-cord reference method . 37
B.1 Applicability of test method . 37
B.2 Apparatus . 37
B.3 Procedure . 37
B.4 Calculations . 38
B.5 Components of reported attenuation . 38
Annex C (normative) Two-cord reference method . 39
C.1 Applicability of test method . 39
C.2 Apparatus . 39
C.3 Procedure . 39
C.4 Calculations . 41
C.5 Components of reported attenuation . 41
Annex D (normative) Equipment cord method . 42
D.1 Applicability of the test method . 42
D.2 Apparatus . 42
D.3 Procedure . 42
D.4 Calculation . 43
D.5 Components of reported attenuation . 44
Annex E (normative) Optical time domain reflectometer . 45
E.1 Applicability of test method . 45
E.2 Apparatus . 45
E.2.1 General . 45
E.2.2 OTDR . 45
E.2.3 Test cords . 45
E.3 Procedure (test method) . 46
E.4 Calculation of attenuation . 47
E.4.1 General . 47
E.4.2 Connection location . 47
E.4.3 Definition of the power levels F and F . 48
1 2
E.4.4 Alternative calculation. 49
E.5 Calculation of optical return loss . 51

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E.6 Calculation of reflectance for discrete components . 53
E.7 OTDR uncertainties . 55
Annex F (normative) Continuous wave optical return loss measurement – Method A. 56
F.1 Applicability of test method . 56
F.2 Apparatus . 56
F.2.1 General . 56
F.2.2 Light source . 56
F.2.3 Branching device or coupler . 56
F.2.4 Power meters . 57
F.2.5 Connector interface . 57
F.2.6 Low reflection termination . 57
F.3 Procedure . 57
F.3.1 Test set characterization. 57
F.3.2 Measurement procedure . 59
F.3.3 Calculations . 59
Annex G (normative) Continuous wave optical return loss measurement – Method B . 61
G.1 Applicability of test method . 61
G.2 Apparatus . 61
G.2.1 General requirements . 61
G.2.2 Known reflectance termination . 61
G.3 Procedure . 62
G.3.1 Set-up characterization . 62
G.3.2 Measurement procedure . 62
G.3.3 Calculation . 63
Annex H (normative) On the use of reference-grade test cords . 64
H.1 General . 64
H.2 Practical configurations and assumptions. 64
H.2.1 Component specifications . 64
H.2.2 Conventions . 65
H.2.3 Reference planes . 65
H.3 Impact of using reference-grade test cords for recommended LSPM methods . 66
H.4 Examples for LSPM measurements . 66
H.4.1 Example 1 (configuration A, one-cord method, Annex A) . 66
H.4.2 Example 2 (configuration B, three-cord method, Annex B) . 67
H.4.3 Example 3 (configuration C, two-cord method, Annex C) . 67
H.4.4 Example 4 – Long haul system (one-cord reference method) . 68
H.5 Impact of using reference-grade test cords for different configurations using
the OTDR test method . 68
H.5.1 Cabling configurations A, B and C . 68
H.5.2 Cabling configuration D . 69
Annex I (informative) OTDR configuration information . 71
I.1 Introductory remarks . 71
I.2 Fundamental parameters that define the operational capability of an OTDR . 72
I.2.1 Dynamic range . 72
I.2.2 Dynamic margin . 72
I.2.3 Pulse width . 72
I.2.4 Averaging time . 72
I.2.5 Dead zone . 72
I.3 Other parameters . 73

IEC 61280-4-2:2024 © IEC 2024 – 5 –
I.3.1 Index of refraction . 73
I.3.2 Measurement range . 73
I.3.3 Distance sampling . 73
I.4 Other measurement configurations . 73
I.4.1 General . 73
I.4.2 Macrobend attenuation measurement . 73
I.4.3 Splice attenuation measurement . 74
I.4.4 Measurement with high reflection connectors or short length cabling . 74
I.4.5 Ghost . 76
I.5 More on the measurement method . 77
I.6 Bi-directional measurement . 78
I.7 OTDR bi-directional trace analysis . 79
I.8 Non-recommended practices. 80
I.8.1 Measurement without tail cord . 80
I.8.2 Two cursors measurement . 80
Annex J (informative) Test cord attenuation verification . 81
J.1 Introductory remarks . 81
J.2 Apparatus . 81
J.3 Procedure . 81
J.3.1 General . 81
J.3.2 Test cord verification for the one-cord and two-cord reference test
methods when using non-pinned or unpinned and non-plug or socket
style connectors . 82
J.3.3 Test cord verification for the one-cord and two-cord reference test
methods using pinned-to-unpinned or plug-to-socket style connectors . 83
J.3.4 Test cord verification for the three-cord reference test method using
non-pinned or unpinned and non-plug or socket style connectors . 85
J.3.5 Test cord verification for the three-cord reference test method using
pinned-to-unpinned or plug-to-socket style connectors . 87
Annex K (informative) Spectral attenuation measurement . 89
K.1 Applicability of test method . 89
K.2 Apparatus . 89
K.2.1 Broadband light source . 89
K.2.2 Optical spectrum analyser . 89
K.3 Procedure . 90
K.3.1 Reference scan . 90
K.3.2 Measurement scan . 90
K.4 Calculations . 90
Bibliography . 91

Figure 1 – Connector symbols . 15
Figure 2 – Symbol for cabling under test . 16
Figure 3 – Configuration A – Start and end of measured attenuations in RTM . 19
Figure 4 – Configuration B – Start and end of measured attenuations in RTM . 20
Figure 5 – Configuration C – Start and end of measured attenuations in RTM . 20
Figure 6 – Configuration D – Start and end of measured attenuations in RTM . 21
Figure 7 – Typical OTDR schematic diagram . 29
Figure 8 – Illustration of return loss test set . 30

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Figure A.1 – One-cord reference measurement . 35
Figure A.2 – One-cord test measurement . 35
Figure B.1 – Three-cord reference measurement . 37
Figure B.2 – Three-cord test measurement . 38
Figure C.1 – Two-cord reference measurement. 40
Figure C.2 – Two-cord test measurement. 40
Figure C.3 – Two-cord test measurement for plug-to-socket style connectors . 40
Figure D.1 – Reference measurement . 43
Figure D.2 – Test measurement . 43
Figure E.1 – Test measurement for OTDR method . 47
Figure E.2 – Location of the cabling under test ports . 48
Figure E.3 – Graphic construction of F and F . 49
1 2
Figure E.4 – Graphic construction of F , F , F and F . 51
1 11 21 2
Figure E.5 – Graphic representation of OTDR ORL measurement . 53
Figure E.6 – Graphic representation of reflectance measurement . 54
Figure F.1 – Return loss test set illustration . 56
Figure F.2 – Measurement of the system internal attenuation P . 58
ref2
Figure F.3 – Measurement of the system internal attenuation P . 58
ref1
Figure F.4 – Measurement of the system reflected power P . 58
rs
Figure F.5 – Measurement of the input power P . 59
in
Figure F.6 – Measurement of the reflected power P . 59
r
Figure G.1 – Return loss test set illustration . 61
Figure G.2 – Measurement of P with reflections suppressed . 62
rs
Figure G.3 – Measurement of P with reference reflector . 62
ref
Figure G.4 – Measurement of the system reflected power P . 63
rs
Figure G.5 – Measurement of the reflected power P . 63
r
Figure H.1 – Cabling configurations A, B and C tested with the OTDR method . 68
Figure H.2 – Cabling configuration D tested with the OTDR method . 70
Figure I.1 – Splice and macrobend attenuation measurement . 74
Figure I.2 – Attenuation measurement with high reflection connectors . 75
Figure I.3 – Attenuation measurement of a short length cabling . 76
Figure I.4 – OTDR trace with ghost . 77
Figure I.5 – Cursor positioning . 78
Figure I.6 – Bi-directional OTDR trace display . 79
Figure I.7 – Bi-directional OTDR trace attenuation analysis . 80
Figure J.1 – Obtaining reference power level P . 83
Figure J.2 – Obtaining power level P . 83
Figure J.3 – Obtaining reference power level P . 84
Figure J.4 – Obtaining power level P . 84
Figure J.5 – Obtaining reference power level P . 85
IEC 61280-4-2:2024 © IEC 2024 – 7 –
Figure J.6 – Obtaining power level P . 85
Figure J.7 – Obtaining reference power level P . 86
Figure J.8 – Obtaining power level P . 87
Figure J.9 – Obtaining power level P . 87
Figure J.10 – Obtaining reference power level P . 88
Figure J.11 – Obtaining power level P . 88
Figure K.1 – Result of spectral attenuation measurement . 90

Table 1 – Cabling configurations . 18
Table 2 – Test methods and configurations . 21
Table 3 – Test limit adjustment and uncertainty related to test cord connector grade . 23
Table 4 – Uncertainty for given fibre length and attenuation at
1 310 nm, 1 550 nm and 1 625 nm . 25
Table 5 – Uncertainty for a given fibre length at 1 310 nm and 1 550 nm using an
OTDR . 26
Table 6 – Spectral requirements . 27
Table E.1 – Typical launch and tail cord lengths . 46
Table H.1 – Expected attenuation for examples . 65
Table H.2 – Test limit adjustment when using reference-grade test cords . 66
Table H.3 – Test limit adjustment when using reference-grade test cords – OTDR test
method . 69
Table I.1 – Example of effective group index of refraction values . 73

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE-OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 4-2: Installed cabling plant –
Single-mode attenuation and optical return loss measurements

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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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)
patent(s). IEC 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, 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 61280-4-2 has been prepared by subcommittee 86C: Fibre optic systems and active
devices, of IEC technical committee 86: Fibre optics. It is an International Standard.
This third edition cancels and replaces the second edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of the equipment cord method;
b) addition of test limit adjustment related to test cord grades;
c) refinements on measurement uncertainties.

IEC 61280-4-2:2024 © IEC 2024 – 9 –
The text of this International Standard is based on the following documents:
Draft Report on voting
86C/1912/FDIS 86C/1916/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.
A list of all parts in the IEC 61280 series, published under the general title Fibre optic
communication subsystem test procedures, can be found on the IEC website.
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.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 10 – IEC 61280-4-2:2024 © IEC 2024
INTRODUCTION
This document is part of a series of IEC standards for measurements of installed fibre optic
cabling plants. This document is applicabl
...