EN IEC 61280-4-1:2019

Fibre-optic communication subsystem test procedures - Part 4-1: Installed cabling plant - Multimode attenuation measurement

IEC 61280-4-1: 2019 is applicable to the measurement of attenuation of installed optical fibre cabling plant using multimode optical fibre. This cabling plant can include multimode optical fibres, connectors, adapters, splices, and other passive devices. The cabling can be installed in a variety of environments including residential, commercial, industrial, and data centre premises, as well as outside plant environments. The test equipment used in this document has one single fibre connector interface or two single fibre connector interfaces. In this document, the optical fibres that are addressed include sub-categories A1-OMx, where x = 2, 3, 4 and 5 (50/125 μm) and A1-OM1 (62,5/125 μm) multimode optical fibres, as specified in IEC 60793-2-10. The attenuation measurements of the other multimode categories can be made using the approaches of this document, but the source conditions for the other categories have not been defined. This third edition cancels and replaces the second edition, published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) changes to Annex F on encircled flux to harmonise with IEC TR 62614-2, but keeping the encircled flux limits defined in Tables F.2 to F.5 unchanged; b) addition of an equipment cord method in Annex D; c) inclusion of testing bend insensitive multimode optical fibre; d) updates to measurement uncertainty; e) definition of additional cabling configurations; f) changes to Table 5 on spectral requirements. Keywords: measurement of attenuation

Prüfverfahren für Lichtwellenleiter-Kommunikationsuntersysteme - Teil 4-1: Lichtwellenleiter-Kabelanlagen - Mehrmoden-Dämpfungsmessungen

Procédures d'essai des sous-systèmes de télécommunication fibroniques - Partie 4-1: Installation câblée - Mesure de l'affaiblissement en multimodal

IEC 61280-4-1: 2019 s'applique au mesurage de l'affaiblissement d'une installation câblée en fibre optique utilisant des fibres optiques multimodales. Cette installation câblée peut inclure des fibres multimodales, des connecteurs, des adaptateurs, des épissures et d'autres dispositifs passifs. Le câblage peut être installé dans une diversité d'environnements, notamment dans des locaux résidentiels, commerciaux ou industriels et des centres de traitement de données, ainsi que dans des environnements d'installations extérieures. L'équipement d'essai utilisé dans le présent document possède une ou deux interfaces de connecteur monofibre. Les fibres optiques qui relèvent du présent document comprennent les fibres optiques multimodales des sous-catégories A1-OMx, où x = 2, 3, 4 et 5 (50/125 μm) et A1-OM1 (62,5/125 μm), spécifiées dans l'IEC 60793-2-10. Les mesurages d'affaiblissement des autres catégories multimodales peuvent être réalisés en adoptant les approches du présent document, mais les conditions de la source n'ont pas été définies. Cette troisième édition annule et remplace la deuxième édition parue en 2009. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) modification de l'Annexe F relative au flux inscrit afin de l'harmoniser par rapport à l'IEC TR 62614-2, mais les limites du flux inscrit définies dans les Tableaux F.2 à F.5 ont été conservées en l'état; b) ajout de la méthode des cordons d'équipement à l'Annexe D; c) ajout d'essais des fibres optiques multimodales insensibles aux courbures; d) mise à jour de l'incertitude de mesure; e) définition de configurations de câblage supplémentaires; g) modifications des exigences spectrales dans le Tableau 5. Mots clés : mesurage de l'affaiblissement

Postopki preskušanja optičnega komunikacijskega podsistema - 4-1. del: Vgrajene žične oblike - Meritev mnogorodovnega slabljenja (IEC 61280-4-1:2019)

Ta del standarda IEC 61280 se uporablja za meritve slabljenja vgrajenega optičnega kabelskega omrežja z večrodovnimi optičnimi vlakni. Ta kabelska inštalacija lahko vključuje večrodovna optična vlakna, konektorje, vmesnike, spojnice in druge pasivne naprave. Kable je mogoče položiti v različnih okoljih, vključno z stanovanjskimi, poslovnimi, industrijskimi prostori in prostori podatkovnih centrov, ter tudi v okoljih zunanjih inštalacij. Preskusna oprema, uporabljena v tem dokumentu, ima en vmesnik konektorjev z enojnim vlaknom ali dva vmesnika konektorjev z enojim vlaknom.
Optična vlakna, ki so obravnavana v tem dokumentu, zajemajo podkategoriji večrodovnih optičnih vlaken A1-OMx, pri čemer je x = 2, 3, 4 in 5 (50/125 μm), ter A1-OM1 (62,5/125 μm), kot je opredeljeno v standardu IEC 60793-2-10. Meritve slabljenja drugih večrodovnih kategorij je mogoče izvesti s pristopi iz tega dokumenta, vendar izvirni pogoji za druge kategorije niso opredeljeni.

General Information

• Status: Published
• Publication Date: 01-Aug-2019
• Withdrawal Date: 25-Jun-2022
• ICS: 33.180.01 - Fibre optic systems in general
• Technical Committee: CLC/SR 86C - Fibre optic systems and active devices
• Drafting Committee: IEC/SC 86C - IEC_SC_86C
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 02-Aug-2019
• Completion Date: 02-Aug-2019
• Ref Project: SIST EN IEC 61280-4-1:2019 - Fibre-optic communication subsystem test procedures - Part 4-1: Installed cable plant - Multimode attenuation measurement (IEC 61280-4-1:2019)

Relations

• Replaces: EN 61280-4-1:2009 - Fibre optic communication subsystem test procedures - Part 4-1: Installed cable plant - Multimode attenuation measurement
• Effective Date: 06-Aug-2019
• Amended By: EN IEC 61280-4-1:2019/A1:2022 - Fibre-optic communication subsystem test procedures - Part 4-1: Installed cabling plant - Multimode attenuation measurement
• Effective Date: 22-Dec-2020
• Corrected By: EN IEC 61280-4-1:2019/AC:2022-12 - Fibre-optic communication subsystem test procedures - Part 4-1: Installed cabling plant - Multimode attenuation measurement
• Effective Date: 03-Jan-2023
• Corrected By: EN IEC 61280-4-1:2019/AC:2020-05 - Fibre-optic communication subsystem test procedures - Part 4-1: Installed cabling plant - Multimode attenuation measurement
• Effective Date: 12-May-2020

Overview

EN IEC 61280-4-1:2019 specifies procedures for the measurement of attenuation in installed multimode optical fibre cabling plant. It applies to multimode fibres, connectors, adapters, splices and other passive devices in residential, commercial, industrial, data centre and outside-plant environments. The standard covers instruments with one or two single‑fibre connector interfaces and addresses multimode fibre categories A1‑OM1 (62.5/125 µm) and A1‑OMx (50/125 µm, x = 2, 3, 4, 5) as defined in IEC 60793‑2‑10. This 2019 (third) edition is a technical revision of the 2009 version with updates to encircled flux alignment, test methods, uncertainty evaluation and support for bend‑insensitive MMF.

Key topics and requirements

• Test scope: Measurement of optical attenuation for installed multimode cabling plant including passive components.
• Test methods: LSPM (light source & power meter) and OTDR procedures are specified, with normative annexes for:
  • One‑cord, Two‑cord and Three‑cord methods
  • Equipment cord method (new in this edition)
  • OTDR test procedures and uncertainty considerations
• Launch and receive cords: Requirements for launch, receive and substitution/test cords to ensure repeatable results.
• Source characteristics: Encircled flux requirements and templates (harmonised with IEC TR 62614‑2) to control launch conditions for multimode attenuation measurement.
• Uncertainty: Guidance and typical uncertainty values for measurements, including effects of test cord grade and power meter calibration.
• Bend-insensitive fibre: Inclusion of procedures to test modern bend‑insensitive multimode fibres.
• Documentation: Required test records, measurement calculations and reporting rules for acceptance testing.

Applications and users

EN IEC 61280-4-1:2019 is intended for:

• Fibre installers and commissioning teams performing acceptance testing and certification of multimode links.
• Test technicians and contractors documenting the measurement of attenuation for handover to customers.
• Data centre operators and network managers validating installed plant performance.
• Test-equipment manufacturers and laboratories developing measurement procedures and calibrations.
• Procurement and compliance teams requiring standardised attenuation test methods for contracts.

Typical uses include link acceptance, baseline documentation, troubleshooting loss issues, and verifying compliance with system loss budgets.

Related standards

Normative and related references include IEC 60793‑2‑10 (fibre categories), IEC 61280‑1‑4 (encircled flux), IEC 61280‑1‑3, IEC 61300‑3‑35, IEC 61746‑2 and others referenced for calibration, connector inspection and OTDR calibration.

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2019
Nadomešča:
SIST EN 61280-4-1:2010
Postopki preskušanja optičnega komunikacijskega podsistema - 4-1. del: Vgrajene
žične oblike - Meritev mnogorodovnega slabljenja (IEC 61280-4-1:2019)
Fibre-optic communication subsystem test procedures - Part 4-1: Installed cable plant -
Multimode attenuation measurement (IEC 61280-4-1:2019)
Prüfverfahren für Lichtwellenleiter-Kommunikationsuntersysteme - Teil 4-1:
Lichtwellenleiter-Kabelanlagen - Mehrmoden-Dämpfungsmessungen (IEC 61280-4-
1:2019)
Procédures d'essai des sous-systèmes de télécommunication à fibres optiques - Partie 4
-1: Installation câblée - Mesure de l'affaiblissement en multimodal (IEC 61280-4-1:2019)
Ta slovenski standard je istoveten z: EN IEC 61280-4-1:2019
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 61280-4-1

NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2019
ICS 33.180.01 Supersedes EN 61280-4-1:2009 and all of its
amendments and corrigenda (if any)
English Version
Fibre-optic communication subsystem test procedures - Part 4-1:
Installed cabling plant - Multimode attenuation measurement
(IEC 61280-4-1:2019)
Procédures d'essai des sous-systèmes de Prüfverfahren für Lichtwellenleiter-
télécommunication fibroniques - Partie 4-1: Installation Kommunikationsuntersysteme - Teil 4-1: Lichtwellenleiter-
câblée - Mesure de l'affaiblissement en multimodal Kabelanlagen - Mehrmoden-Dämpfungsmessungen
(IEC 61280-4-1:2019) (IEC 61280-4-1:2019)
This European Standard was approved by CENELEC on 2019-06-26. 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,
Turkey 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
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61280-4-1:2019 E

European foreword
The text of document 86C/1575/FDIS, future edition 3 of IEC 61280-4-1, 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 61280-4-1:2019.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-03-26
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-06-26
document have to be withdrawn
This document supersedes EN 61280-4-1:2009 and all of its amendments and corrigenda (if any)
This edition constitutes a technical revision including the following significant technical changes with
respect to the previous edition:
a) changes to Annex F on encircled flux to harmonise with IEC TR 62614-2, but keeping the encircled
flux limits defined in Tables F.2 to F.5 unchanged;
b) addition of an equipment cord method in Annex D;
c) inclusion of testing bend insensitive multimode optical fibre;
d) updates to measurement uncertainty;
e) definition of additional cabling configurations;
f) changes to Table 5 on spectral requirements.
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.
Endorsement notice
The text of the International Standard IEC 61280-4-1:2019 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 standards
indicated:
IEC 60793-1-40 NOTE Harmonized as EN IEC 60793-1-40
IEC 60793-2 NOTE Harmonized as EN 60793-2
IEC 60793-2-10 NOTE Harmonized as EN 60793-2-10
IEC 60793-2-50 NOTE Harmonized as EN IEC 60793-2-50
IEC 60794-2-21 NOTE Harmonized as EN IEC 60794-2-21
IEC 61300-3-6 NOTE Harmonized as EN 61300-3-6
IEC 61300-3-45 NOTE Harmonized as EN 61300-3-45
IEC 61745 NOTE Harmonized as EN 61745
IEC 61755-6-2 NOTE Harmonized as EN IEC 61755-6-2
IEC 62664-1-1 NOTE Harmonized as EN 62664-1-1
IEC 62614:2010 NOTE Harmonized as EN 62614:2010 (not modified)
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.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60825-2 -  Safety of laser products - Part 2: Safety of EN 60825-2 -
optical fibre communication systems
(OFCS)
IEC 61280-1-3 -  Fibre optic communication subsystem test EN 61280-1-3 -
procedures - Part 1-3: General
communication subsystems - Central
wavelength and spectral width
measurement
IEC 61280-1-4 -  Fibre optic communication subsystem test EN 61280-1-4 -
procedures - Part 1-4: General
communication subsystems - Light source
encircled flux measurement method
IEC 61300-3-35 -  Fibre optic interconnecting devices and EN 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 61746-2 -  Calibration of optical time-domain EN 61746-2 -
reflectometers (OTDR) - Part 2: OTDR for
multimode fibres
IEC 61280-4-1 ®
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre-optic communication subsystem test procedures –

Part 4-1: Installed cabling plant – Multimode attenuation measurement

Procédures d'essai des sous-systèmes de télécommunication fibroniques –

Partie 4-1: Installation câblée – Mesure de l'affaiblissement en multimodal

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.01 ISBN 978-2-8322-6893-3

– 2 – IEC 61280-4-1:2019 © IEC 2019
CONTENTS
FOREWORD . 7
1 Scope . 9
2 Normative references . 9
3 Terms, definitions, graphical symbols and abbreviated terms. 9
3.1 Terms and definitions . 10
3.2 Graphical symbols . 12
3.3 Abbreviated terms . 14
4 Test methods . 14
4.1 General . 14
4.2 Cabling configurations and applicable test methods . 15
5 Overview of uncertainties . 17
5.1 General . 17
5.2 Sources of significant uncertainties . 17
5.3 Consideration of the PM . 18
5.4 Consideration of test cord connector grade . 18
5.5 Typical uncertainty values . 18
6 Apparatus . 19
6.1 General . 19
6.2 Light source . 19
6.2.1 Stability . 19
6.2.2 Spectral characteristics (LSPM measurement) . 19
6.3 Launch cord . 20
6.4 Receive or tail cord . 20
6.5 Substitution cord . 21
6.6 Power meter – LSPM methods only. 21
6.7 OTDR apparatus . 21
6.8 Connector end face cleaning and inspection equipment . 22
6.9 Adapters . 22
7 Procedures . 22
7.1 General . 22
7.2 Common procedures . 22
7.2.1 Care of the test cords . 22
7.2.2 Make reference measurements (LSPM methods only). 22
7.2.3 Inspect and clean the ends of the optical fibres in the cabling . 22
7.2.4 Make the measurements . 23
7.2.5 Make the calculations . 23
7.2.6 Duplex and bi-directional testing . 23
7.3 Calibration . 23
7.4 Safety . 23
8 Calculations . 23
9 Documentation . 23
9.1 Information for each test . 23
9.2 Information to be available . 24
Annex A (normative) One-cord method . 25
A.1 Applicability of test method . 25

IEC 61280-4-1:2019 © IEC 2019 – 3 –
A.2 Apparatus . 25
A.3 Procedure . 25
A.4 Calculation . 26
A.5 Components of reported attenuation . 26
Annex B (normative) Three-cord method . 27
B.1 Applicability of test method . 27
B.2 Apparatus . 27
B.3 Procedure . 27
B.4 Calculations . 28
B.5 Components of reported attenuation . 28
Annex C (normative) Two-cord method . 29
C.1 Applicability of test method . 29
C.2 Apparatus . 29
C.3 Procedure . 29
C.4 Calculations . 30
C.5 Components of reported attenuation . 30
Annex D (normative) Equipment cord method . 32
D.1 Applicability of the test method . 32
D.2 Apparatus . 32
D.3 Procedure . 32
D.4 Calculation . 33
D.5 Components of reported attenuation . 33
D.6 Typical uncertainty values . 34
Annex E (normative) Optical time domain reflectometer . 35
E.1 Applicability of the test method . 35
E.2 Apparatus . 35
E.2.1 General . 35
E.2.2 OTDR . 35
E.2.3 Test cords . 35
E.3 Procedure (test method) . 36
E.4 Calculation . 37
E.4.1 General . 37
E.4.2 Connection location . 37
E.4.3 Definition of power levels F and F . 38
1 2
E.4.4 Alternative calculation. 38
E.5 OTDR uncertainties . 40
Annex F (normative) Requirements for the source characteristics . 42
F.1 Encircled flux . 42
F.2 Assumptions and limitations . 42
F.3 Encircled flux templates . 42
F.3.1 General . 42
F.3.2 Uncertainties expectations . 43
F.3.3 Templates. 43
F.4 Graphical representation of templates . 44
Annex G (informative) OTDR configuration information . 46
G.1 General . 46
G.2 Fundamental parameters that define the operational capability of an OTDR . 47
G.2.1 Dynamic range . 47

– 4 – IEC 61280-4-1:2019 © IEC 2019
G.2.2 Pulse width . 47
G.2.3 Averaging time . 47
G.2.4 Dead zone . 47
G.3 Other parameters . 47
G.3.1 Index of refraction . 47
G.3.2 Measurement range . 48
G.3.3 Distance sampling . 48
G.4 Other measurement configurations . 48
G.4.1 General . 48
G.4.2 Macrobend or splice attenuation measurement . 48
G.4.3 Splice attenuation measurement . 49
G.4.4 Measurement with high reflection connectors or short length cabling . 49
G.4.5 Ghost . 51
G.5 More on the measurement method . 52
G.6 Bi-directional measurement . 53
G.7 Non-recommended practices. 54
G.7.1 Measurement without tail test cord . 54
G.7.2 Cursor measurement . 54
Annex H (informative) Test cord attenuation verification . 55
H.1 General . 55
H.2 Apparatus . 55
H.3 Procedure . 55
H.3.1 General . 55
H.3.2 Test cord verification for the one-cord and two-cord methods when
using non-pinned/unpinned and non-plug/socket style connectors . 56
H.3.3 Test cord verification for the one-cord and two-cord methods when
using pinned/unpinned or plug/socket style connectors . 57
H.3.4 Test cord verification for the three-cord method when using non-
pinned/unpinned and non-plug/socket style connectors . 59
H.3.5 Test cord verification for the three-cord method when using
pinned/unpinned or plug/socket style connectors . 61
Annex I (normative) On the use of reference-grade test cords. 63
I.1 General . 63
I.2 Practical configurations and assumptions. 63
I.2.1 Component specifications . 63
I.2.2 Conventions . 64
I.2.3 Reference planes . 64
I.3 Impact of using reference grade test cords for recommended LSPM methods . 64
I.4 Examples for LSPM measurements . 65
I.4.1 Example 1 (configuration A, 1-C method – Annex A) . 65
I.4.2 Example 2 (configuration D, EC method – Annex D) . 65
I.5 Impact of using reference-grade test cords for different configurations using
the OTDR test method . 66
I.5.1 Cabling configurations A, B and C . 66
I.5.2 Cabling configuration D . 67
Annex J (informative) Launch cord output near-field verification. 69
J.1 Direct verification . 69
J.2 Test equipment manufacturer verification . 69
J.3 Field check with physical artefact . 69
J.3.1 General . 69

IEC 61280-4-1:2019 © IEC 2019 – 5 –
J.3.2 Procedure for attenuation characterization of artefacts . 71
J.3.3 Construction details . 71
J.3.4 Example results . 72
Bibliography . 76

Figure 1 – Connector symbols . 13
Figure 2 – Symbol for cabling under test . 13
Figure 3 – Reference plane for configuration A tested with the 1-cord method . 16
Figure 4 – Reference plane for configuration B tested with the 3-cord method . 16
Figure 5 – Reference plane for configuration C tested with the 2-cord method . 17
Figure 6 – Reference plane for configuration D tested with the EC method . 17
Figure 7 – OTDR schematic . 21
Figure A.1 – Reference measurement . 26
Figure A.2 – Test measurement . 26
Figure B.1 – Reference measurement . 27
Figure B.2 – Test measurement . 28
Figure C.1 – Reference measurement . 29
Figure C.2 – Test measurement . 30
Figure C.3 – Test measurement for plug-socket style connectors . 30
Figure D.1 – Reference measurement . 33
Figure D.2 – Test measurement . 33
Figure E.1 – OTDR method . 36
Figure E.2 – Location of the ports of the cabling under test . 37
Figure E.3 – Graphic construction of F and F . 38
1 2
Figure E.4 – Graphic construction of F , F , F and F . 40
1 11 12 2
Figure F.1 – Encircled flux example . 45
Figure G.1 – Splice and macrobend attenuation measurement . 49
Figure G.2 – Attenuation measurement with high reflection connectors . 50
Figure G.3 – Attenuation measurement of a short length cabling. 51
Figure G.4 – OTDR trace with ghost . 52
Figure G.5 – Cursor positioning . 53
Figure H.1 – Obtaining reference power level P . 57
Figure H.2 – Obtaining power level P . 57
Figure H.3 – Obtaining reference power level P . 58
Figure H.4 – Obtaining power level P . 58
Figure H.5 – Obtaining reference power level P . 59
Figure H.6 – Obtaining power level . 59
Figure H.7 – Obtaining reference power level P . 60
Figure H.8 – Obtaining power level P . 60
Figure H.9 – Obtaining power level P . 61
Figure H.10 – Obtaining reference power level P . 62
– 6 – IEC 61280-4-1:2019 © IEC 2019
Figure H.11 – Obtaining power level P . 62
Figure I.1 – Cabling configurations A, B and C tested with the OTDR method . 66
Figure I.2 – Cabling configuration D tested with the OTDR method . 68
Figure J.1 – Initial power measurement . 70
Figure J.2 – Verification of reference-grade connection . 70
Figure J.3 – Two offset splices . 70
Figure J.4 – Five offset splices . 71
Figure J.5 – EF centred . 72
Figure J.6 – EF underfilling . 73
Figure J.7 – EF overfilling . 73
Figure J.8 – L1 attenuation with mandrel. 74
Figure J.9 – L1 attenuation with mandrel and mode conditioner . 74
Figure J.10 – L2 attenuation with mandrel . 74
Figure J.11 – L2 attenuation with mandrel and mode conditioning . 75
Figure J.12 – L3 attenuation with mandrel . 75
Figure J.13 – L3 attenuation with mandrel and mode conditioning . 75

Table 1 – Cabling configurations . 15
Table 2 – Test methods and configurations . 15
Table 3 – Measurements bias related to test cord connector grade . 18
Table 4 – Uncertainty for a given attenuation at 850 nm . 19
Table 5 – Spectral requirements . 19
Table D.1 – Uncertainty for a given attenuation at 850 nm . 34
Table F.1 – Attenuation, threshold tolerance and confidence level . 43
Table F.2 – EF requirements for 50 µm core optical fibre cabling at 850 nm . 43
Table F.3 – EF requirements for 50 μm core optical fibre cabling at 1 300 nm. 44
Table F.4 – EF requirements for 62,5 μm core optical fibre cabling at 850 nm. 44
Table F.5 – EF requirements for 62,5 μm core optical fibre cabling at 1 300 nm . 44
Table G.1 – Default effective group index of refraction values . 48
Table I.1 – Measurement bias when using reference-grade test cords . 65
Table I.2 – Measurement bias when using reference grade test cords – OTDR test
method . 67

IEC 61280-4-1:2019 © IEC 2019 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE-OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 4-1: Installed cabling plant – Multimode attenuation measurement

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
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International Standard IEC 61280-4-1 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
This third edition cancels and replaces the second edition, published in 2009. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) changes to Annex F on encircled flux to harmonise with IEC TR 62614-2, but keeping the
encircled flux limits defined in Tables F.2 to F.5 unchanged;
b) addition of an equipment cord method in Annex D;
c) inclusion of testing bend insensitive multimode optical fibre;
d) updates to measurement uncertainty;
e) definition of additional cabling configurations;
f) changes to Table 5 on spectral requirements.

– 8 – IEC 61280-4-1:2019 © IEC 2019
The text of this International Standard is based on the following documents:
FDIS Report on voting
86C/1575/FDIS 86C/1592/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication 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.

IEC 61280-4-1:2019 © IEC 2019 – 9 –
FIBRE-OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 4-1: Installed cabling plant – Multimode attenuation measurement

1 Scope
This part of IEC 61280 is applicable to the measurement of attenuation of installed optical fibre
cabling plant using multimode optical fibre. This cabling plant can include multimode optical
fibres, connectors, adapters, splices, and other passive devices. The cabling can be installed
in a variety of environments including residential, commercial, industrial, and data centre
premises, as well as outside plant environments. The test equipment used in this document has
one single fibre connector interface or two single fibre connector interfaces.
In this document, the optical fibres that are addressed include sub-categories A1-OMx, where
x = 2, 3, 4 and 5 (50/125 μm) and A1-OM1 (62,5/125 μm) multimode optical fibres, as specified
in IEC 60793-2-10. The attenuation measurements of the other multimode categories can be
made using the approaches of this document, but the source conditions for the other categories
have not been defined.
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.
IEC 60825-2, Safety of laser products – Part 2: Safety of optical fibre communication systems
(OFCS)
IEC 61280-1-3, Fibre optic communication subsystem test procedures – Part 1-3: General
communication subsystems – Central wavelength and spectral width measurement
IEC 61280-1-4, Fibre optic communication subsystem test procedures – Part 1-4: General
communication subsystems – Light source encircled flux measurement method
IEC 61300-3-35, Fibre optic interconnecting devices and 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
IEC 61746-2, Calibration of optical time-domain reflectometers (OTDR) – Part 2: OTDR for
multimode fibres
3 Terms, definitions, graphical symbols and abbreviated terms
For the purposes of this document, the following terms, definitions, graphical symbols and
abbreviated terms apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
– 10 – IEC 61280-4-1:2019 © IEC 2019
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

3.1 Terms and definitions
3.1.1
attenuation
A
reduction of optical power induced by transmission through a medium such as cabling
A = 10 log(P /P )
in out
where
P and P are the power, typically measured in mW, into and out of the cabling
in out
Note 1 to entry: Attenuation is expressed in dB.
3.1.2
light source power meter
LSPM
test system consisting of a light source (LS) and power meter (PM) used to measure the
attenuation of installed cabling plant
3.1.3
optical time domain reflectometer
OTDR
test system consisting of an optical time-domain reflectometer instrument used to characterize
and measure the attenuation of installed cabling plant and specific elements within that cabling
plant
Note 1 to entry: This note applies to the French language only.
3.1.4
test cord
terminated optical fibre cord used to connect the optical source or detector to the cabling, or to
provide suitable interfaces to the cabling under test
Note 1 to entry: There are five types of test cords:
– launch cord: used to connect the light source to the cabling;
– receive cord: used to connect the cabling to the power meter (LSPM only);
– tail cord: attached to the far end of the cabling when an OTDR is used at the near end. This provides a means
of evaluating attenuation of the whole of the cabling including the far end connection;
– adapter cord: used to transition between sockets or other incompatible connectors in a required test configuration;
– substitution cord: a test cord used within a reference measurement which is replaced during the measurement
of the attenuation of the cabling under test.
3.1.5
bi-directional measurement
two measurements of the same optical fibre, made by launching light into opposite ends of that
fibre
3.1.6
configuration
form or arrangements of parts or elements such as terminat
...