IEC 61280-4-5:2020

Fibre-optic communication subsystem test procedures - Part 4-5: Installed cabling plant - Attenuation measurement of MPO terminated fibre optic cabling plant using test equipment with MPO interfaces

IEC 61280-4-5:2020 is applicable to the measurement of attenuation and determination of polarity and length of installed multimode and single-mode optical fibre cabling plant, terminated with MPO connectors, using test equipment having an MPO interface. This cabling plant can include multimode or single-mode 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. In this document, the optical fibres that are addressed include sub-categories A1-OMx, where x = 2, 3, 4 and 5 (50/125 μm) multimode optical fibres, as specified in IEC 60793-2-10, and category B-652 and B-657 (9/125 μm) single-mode optical fibres, as specified in IEC 60793-2-50. The attenuation measurements of the other multimode and single-mode categories can also be made using a light source and power meter (LSPM) or optical time domain reflectometer (OTDR) utilising an internal or external optical switch having one MPO interface. Multimode measurements are made with an 850 nm source because transceivers used for parallel optics applications having an MPO interface only operate at 850 nm; 1 300 nm measurements are optional. Single-mode measurements are made with a 1 310 nm and/or 1 550 nm source because transceivers used for parallel optics applications having an MPO interface operate at these wavelengths. This document does not include descriptions of cabling that is not exclusively MPO to MPO.
The contents of the corrigendum of January 2022 have been included in this copy.

Procédures d'essai des sous-systèmes de télécommunication fibroniques - Partie 4-5: Installation câblée - Mesurage de l’affaiblissement de l’installation câblée à fibres optiques à terminaisons MPO utilisant un équipement d’essai avec interfaces MPO

IEC 61280-4-5:2020 s'applique au mesurage de l'affaiblissement et à la détermination de la polarité et de la longueur d’une installation câblée à fibres optiques multimodales et unimodales, avec terminaisons par connecteurs MPO, utilisant un équipement d’essai à interface MPO. Cette installation câblée peut inclure des fibres optiques multimodales ou unimodales, des connecteurs, des adaptateurs, des épissures et d'autres dispositifs passifs. Le câblage peut être installé dans différents environnements, y compris des locaux résidentiels, commerciaux ou industriels et des centres de traitement de données, ainsi que dans des environnements d'installations extérieures.Les fibres optiques traitées dans le présent document comprennent les fibres optiques multimodales des sous-catégories A1-OMx, où x = 2, 3, 4 et 5 (50/125 μm), telles que spécifiées dans l’IEC 60793-2-10, et les fibres optiques unimodales des catégories B‑652 et B‑657 (9/125 μm), telles que spécifiées dans l'IEC 60793-2-50. Les mesurages de l’affaiblissement des autres catégories multimodales et unimodales peuvent également être effectués en utilisant une source lumineuse et un mesureur de puissance (MPSL) ou un réflectomètre optique dans le domaine temporel (OTDR – optical time domain reflectometer) avec commutateur optique interne ou externe à interface MPO. Les mesurages des catégories multimodales sont effectués avec une source lumineuse de 850 nm étant donné que les émetteurs-récepteurs utilisés pour les applications optiques parallèles à interface MPO fonctionnent uniquement avec une source lumineuse de 850 nm. Les mesurages avec une source lumineuse de 1 300 nm sont facultatifs. Les mesurages des catégories unimodales sont effectués avec une source lumineuse de 1 310 nm et/ou 1 550 nm étant donné que les émetteurs-récepteurs utilisés pour les applications optiques parallèles à interface MPO fonctionnent à ces longueurs d’onde. Le présent document ne comprend pas les descriptions du câblage qui n’utilise pas exclusivement une interface MPO/MPO.
Le contenu du corrigendum de janvier 2022 a été pris en considération dans cet exemplaire.

General Information

• Status: Published
• Publication Date: 21-Jul-2020
• ICS: 33.180.01 - Fibre optic systems in general
• Technical Committee: SC 86C - Fibre optic systems, sensing and active devices
• Drafting Committee: WG 1 - TC 86/SC 86C/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 22-Jul-2020
• Completion Date: 21-Aug-2020

Relations

• Corrected By: IEC 61280-4-5:2020/COR1:2022 - Corrigendum 1 - Fibre-optic communication subsystem test procedures - Part 4-5: Installed cabling plant - Attenuation measurement of MPO terminated fibre optic cabling plant using test equipment with MPO interfaces
• Effective Date: 05-Sep-2023

Overview

IEC 61280-4-5:2020 specifies test procedures for the attenuation measurement and determination of polarity and length of installed multimode and single‑mode fibre‑optic cabling plants that are terminated with MPO connectors and tested using equipment with MPO interfaces. The standard covers cabling that may include fibres, connectors, adapters, splices and passive devices installed in residential, commercial, industrial, data‑centre and outside‑plant environments. The published edition includes the January 2022 corrigendum.

Key technical scope points:

• Addresses multimode sub‑categories A1‑OMx (x = 2,3,4,5; 50/125 μm) and single‑mode B‑652 / B‑657 (9/125 μm) as defined in IEC 60793 series.
• Multimode measurements: 850 nm source (1300 nm optional) because parallel‑optics MPO transceivers operate at 850 nm.
• Single‑mode measurements: 1 310 nm and/or 1 550 nm sources for MPO parallel optics.
• Supports measurement using LSPM (light source + power meter) and OTDR methods, including use of internal/external optical switches with MPO interfaces.
• Applies only to cabling that is exclusively MPO to MPO.

Key Topics and Requirements

• Test methods and configurations: one‑cord, three‑cord, adapter‑cord, equipment cord methods, and OTDR procedures (normative annexes provide step‑by‑step methods).
• Apparatus specifications: light source stability, spectral characteristics, launch/receive cords, power meters, OTDR settings and external switch considerations.
• Uncertainty and calibration: overview of significant uncertainty sources, typical uncertainty values for multimode and single‑mode testing, and calibration requirements.
• Test cord verification and maintenance: procedures for verifying test cord and cassette attenuation, connector end‑face cleaning and inspection.
• Polarity and length determination: procedures to determine multi‑fibre polarity and accurate fibre length using MPO test interfaces.
• Documentation and reporting: required information to record for each test and overall test documentation.

Practical Applications and Who Uses It

IEC 61280‑4‑5 is intended for:

• Fibre installers and commissioning technicians performing acceptance tests on MPO‑terminated systems.
• Data centre cabling teams validating high‑density parallel optics links (e.g., 40G/100G/400G).
• Network integrators and auditors reporting attenuation, polarity and link length.
• Manufacturers of test equipment and MPO components to ensure conformance with measurement methods. Practical uses include acceptance testing, troubleshooting, commissioning of parallel‑optics trunks, and verification of passive MPO infrastructure.

Related Standards

• IEC 60793‑2‑10 (multimode fibre categories A1‑OMx)
• IEC 60793‑2‑50 (single‑mode fibre categories B‑652, B‑657)
• IEC 61280 series (other parts covering fibre‑optic subsystem test procedures)

Keywords: IEC 61280-4-5, MPO, attenuation measurement, installed cabling plant, multimode, single‑mode, LSPM, OTDR, data centre testing, test cords, polarity.

Standards Content (Sample)

IEC 61280-4-5 ®
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STANDARD
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Fibre-optic communication subsystem test procedures –
Part 4-5: Installed cabling plant – Attenuation measurement of MPO terminated
fibre optic cabling plant using test equipment with MPO interfaces
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IEC 61280-4-5 ®
Edition 1.0 2020-07
INTERNATIONAL
STANDARD
colour
inside
Fibre-optic communication subsystem test procedures –

Part 4-5: Installed cabling plant – Attenuation measurement of MPO terminated

fibre optic cabling plant using test equipment with MPO interfaces

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.01 ISBN 978-2-8322-8670-8

– 2 – IEC 61280-4-5:2020 © IEC 2020
CONTENTS
FOREWORD . 7
1 Scope . 9
2 Normative references . 9
3 Terms, definitions, graphical symbols and abbreviated terms. 10
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 . 16
5.1 General . 16
5.2 Sources of significant uncertainties . 16
5.3 Consideration of the PM . 17
5.4 Consideration of test cord connector grade . 17
5.5 Typical uncertainty values for multimode testing . 17
5.6 Typical uncertainty values for single-mode testing . 19
6 Apparatus . 20
6.1 General . 20
6.2 Light source . 20
6.2.1 General . 20
6.2.2 Stability . 20
6.2.3 Spectral characteristics (LSPM measurement) . 21
6.3 Launch cord . 21
6.4 Receive or tail cord . 22
6.5 Substitution cord . 22
6.6 Adapter cord . 23
6.7 Power meter – LSPM methods only. 23
6.8 OTDR apparatus . 24
6.9 Connector end face cleaning and inspection equipment . 24
6.10 Adapters . 24
7 Procedures . 24
7.1 General . 24
7.2 Common procedures . 25
7.2.1 Care of the test cords . 25
7.2.2 Take reference measurements. 25
7.2.3 Inspect and clean the ends of the optical fibres in the cabling . 25
7.2.4 Take the measurements . 25
7.2.5 Make the calculations . 25
7.2.6 Multi-fibre and bi-directional testing . 25
7.3 Calibration . 26
7.4 Safety . 26
8 Calculations . 26
9 Documentation . 26
9.1 Information for each test . 26
9.2 Information to be available . 26

Annex A (normative) One-cord method . 27
A.1 Applicability of the test method . 27
A.2 Apparatus . 27
A.3 Procedure for unpinned to unpinned cabling with unpinned power meter . 27
A.4 Procedure for unpinned to pinned cabling with unpinned power meter . 28
A.5 Procedure for pinned to pinned cabling with pinned power meter . 29
A.6 Procedure for unpinned to unpinned cabling with pinned power meter and
gender-neutral test cord . 30
A.7 Calculation . 31
A.8 Components of reported attenuation . 31
Annex B (normative) Three-cord method . 32
B.1 Applicability of the test method . 32
B.2 Apparatus . 32
B.3 Procedure for unpinned to unpinned cabling . 32
B.4 Procedure for unpinned to pinned cabling . 33
B.5 Procedure for pinned to pinned cabling . 34
B.6 Procedure, channel test (general) . 35
B.7 Calculations . 36
B.8 Components of reported attenuation . 36
Annex C (normative) Adapter-cord method . 37
C.1 Applicability of the test method . 37
C.2 Apparatus . 37
C.3 Procedure for unpinned to unpinned cabling with pinned power meter . 37
C.4 Procedure for unpinned to pinned cabling with pinned power meter . 38
C.5 Procedure for pinned to unpinned cabling with unpinned power meter . 39
C.6 Procedure for pinned to pinned cabling with unpinned power meter . 40
C.7 Calculations . 41
C.8 Components of reported attenuation . 42
Annex D (normative) Equipment cord method . 43
D.1 Applicability of the test method . 43
D.2 Apparatus . 43
D.3 Procedure . 43
D.4 Calculation . 44
D.5 Components of reported attenuation . 44
D.6 Typical uncertainty values . 45
Annex E (normative) Optical time domain reflectometer . 46
E.1 Applicability of the test method . 46
E.2 Apparatus . 46
E.2.1 General . 46
E.2.2 OTDR . 46
E.2.3 Test cords . 47
E.3 Procedure (test method) . 47
E.4 Calculation . 48
E.4.1 General . 48
E.4.2 Connection location . 48
E.4.3 Definition of the power levels F and F . 49
1 2
E.4.4 Alternative calculation. 50
E.5 OTDR uncertainties . 52

– 4 – IEC 61280-4-5:2020 © IEC 2020
Annex F (normative) Requirements for the multimode source characteristics . 53
Annex G (informative) OTDR configuration information . 54
G.1 General . 54
G.2 Other measurement configurations . 54
G.2.1 General . 54
G.2.2 Measurement with low return loss connectors or short length cabling . 54
G.2.3 Measurement with APC connectors . 56
Annex H (informative) Test cord, breakout cord, and cassette attenuation verification . 58
H.1 General . 58
H.2 Apparatus . 58
H.3 General procedure . 58
H.3.1 Overview . 58
H.3.2 Test cord verification . 59
H.3.3 Cassette and breakout cord verification . 60
H.4 Test cord verification prior to cabling measurement . 61
H.4.1 General . 61
H.4.2 Procedure for unpinned to unpinned cabling measurement . 61
H.4.3 Procedure for unpinned to pinned cabling measurement . 62
H.4.4 Procedure for pinned to pinned cabling measurement . 63
Annex I (normative) On the use of low attenuation grade test cords . 66
I.1 General . 66
I.2 Practical configurations and assumptions. 66
I.2.1 Component specifications . 66
I.2.2 Conventions . 67
I.2.3 Reference planes . 67
I.3 Impact of using low attenuation grade test cords for recommended LSPM
methods . 68
I.4 Examples for LSPM measurements . 68
I.4.1 Example 1: Configuration Au-u, 1-C method (Annex A) . 68
I.4.2 Example 2: Configuration Du-u, EC method (Annex D) . 69
I.5 Impact of using reference grade test cords for different configurations using
the OTDR test method . 69
I.5.1 Cabling configurations Au-u, Ap-u and Ap-p . 69
I.5.2 Cabling configuration Du-u . 70
Bibliography . 72

Figure 1 – Connector and apparatus symbols . 13
Figure 2 – Symbol for cabling under test . 14
Figure 3 – OTDR schematic with external optical switch . 24
Figure A.1 – Reference measurement for unpinned to unpinned cabling using unpinned
power meter . 28
Figure A.2 – Test measurement for unpinned to unpinned cabling using unpinned
power meter . 28
Figure A.3 – Reference measurement for unpinned to pinned cabling using unpinned
power meter . 29
Figure A.4 – Test measurement for unpinned to pinned cabling using unpinned power
meter . 29
Figure A.5 – Reference measurement for pinned to pinned cabling using pinned power
meter . 30

Figure A.6 – Test measurement for pinned to pinned cabling using pinned power meter . 30
Figure A.7 – Reference measurement for unpinned to unpinned cabling using pinned
power meter . 31
Figure A.8 – Test measurement for unpinned to unpinned cabling (gender-neutral TC1)
using pinned power meter . 31
Figure B.1 – Reference measurement for unpinned to unpinned cabling using pinned
power meter . 33
Figure B.2 – Test measurement for unpinned to unpinned cabling using pinned power
meter . 33
Figure B.3 – Reference measurement for unpinned to pinned cabling using pinned
power meter . 34
Figure B.4 – Test measurement for unpinned to pinned cabling using pinned power
meter . 34
Figure B.5 – Reference measurement for pinned to pinned cabling using unpinned
power meter . 35
Figure B.6 – Test measurement for pinned to pinned cabling using unpinned power
meter . 35
Figure B.7 – Reference measurement for channel test using unpinned power meter . 36
Figure B.8 – Test measurement for channel test using unpinned power meter . 36
Figure C.1 – Reference measurement for unpinned to unpinned cabling using pinned
power meter . 38
Figure C.2 – Test measurement for unpinned to unpinned cabling using pinned power
meter . 38
Figure C.3 – Reference measurement for unpinned to pinned cabling using pinned
power meter . 39
Figure C.4 – Test measurement for unpinned to pinned cabling using pinned power
meter . 39
Figure C.5 – Reference measurement for unpinned to pinned cabling using unpinned
power meter . 40
Figure C.6 – Test measurement for unpinned to pinned cabling using unpinned power
meter . 40
Figure C.7 – Reference measurement for unpinned to pinned cabling using unpinned
power meter . 41
Figure C.8 – Test measurement for unpinned to pinned cabling using unpinned power
meter . 41
Figure D.1 – Reference measurement using pinned power meter . 44
Figure D.2 – Test measurement using pinned power meter . 44
Figure E.1 – OTDR method . 48
Figure E.2 – Location of the ports of the cabling under test . 49
Figure E.3 – Graphic construction of F and F . 50
1 2
Figure E.4 – Graphic construction of F , F , F and F . 51
1 11 12 2
Figure G.1 – Attenuation measurement with low return loss connectors . 55
Figure G.2 – Attenuation measurement of a short length cabling. 56
Figure G.3 – Attenuation measurement with APC MPO connections . 57
Figure H.1 – Obtaining reference power level P . 59
Figure H.2 – Obtaining power level P . 59
Figure H.3 – Obtaining reference power level P . 60
– 6 – IEC 61280-4-5:2020 © IEC 2020
Figure H.4 – Obtaining power level P . 60
Figure H.5 – Test measurement for unpinned to unpinned cabling . 61
Figure H.6 – Step 1: obtaining reference power level P . 61
Figure H.7 – Step 2: verification cords, obtaining power level P . 62
Figure H.8 – Test measurement for unpinned to pinned cabling . 62
Figure H.9 – Step 1: obtaining reference power level P . 63
Figure H.10 – Step 2: obtaining power level P . 63
Figure H.11 – Test measurement for pinned to pinned cabling . 63
Figure H.12 – Step 1: obtaining reference power level P . 64
Figure H.13 – Step 2: verification of cords, obtaining power level P . 64
Figure H.14 – Step 3: verification of receive cord, obtaining power level P . 65
Figure I.1 – Cabling configurations Au-u, Ap-u and Ap-p tested with OTDR method . 70
Figure I.2 – Cabling configuration Du-u tested with OTDR method . 71

Table 1 – Cabling configurations . 16
Table 2 – Test methods and configurations . 16
Table 3 – Measurements bias related to test cord connector grade . 17
Table 4 – Uncertainty for a given attenuation at 850 nm using same photodetector . 18
Table 5 – Uncertainty for a given attenuation at 850 nm using different photodetectors . 19
Table 6 – Uncertainty for a given attenuation at 1 310 nm using same photodetector . 19
Table 7 – Uncertainty for a given attenuation at 1 310 nm using different
photodetectors . 20
Table 8 – Spectral requirements . 21
Table D.1 – Uncertainty for a given attenuation when equipment cord method is used . 45
Table I.1 – Measurement bias adjustment when using low attenuation grade test cords . 68
Table I.2 – Acceptance figure adjustment using low attenuation grade test cords –
OTDR method . 70

INTERNATIONAL ELECTROTECHNICAL COMMISSION
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FIBRE-OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 4-5: Installed cabling plant –
Attenuation measurement of MPO terminated fibre
optic cabling plant using test equipment with MPO interfaces

FOREWORD
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International Standard IEC 61280-4-5 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
The text of this International Standard is based on the following documents:
FDIS Report on voting
86C/1669/FDIS 86C/1679/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.
A list of all the parts in the IEC 61280 series, under the general title Fibre-optic communication
subsystem test procedures, can be found on the IEC website.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 8 – IEC 61280-4-5:2020 © IEC 2020
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FIBRE-OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 4-5: Installed cabling plant –
Attenuation measurement of MPO terminated fibre
optic cabling plant using test equipment with MPO interfaces

1 Scope
This part of IEC 61280 is applicable to the measurement of attenuation and determination of
polarity and length of installed multimode and single-mode optical fibre cabling plant, terminated
with MPO connectors, using test equipment having an MPO interface. This cabling plant can
include multimode or single-mode 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.
In this document, the optical fibres that are addressed include sub-categories A1-OMx, where
x = 2, 3, 4 and 5 (50/125 μm) multimode optical fibres, as specified in IEC 60793-2-10, and
category B-652 and B-657 (9/125 μm) single-mode optical fibres, as specified in
IEC 60793-2-50. The attenuation measurements of the other multimode and single-mode
categories can also be made using a light source and power meter (LSPM) or optical time
domain reflectometer (OTDR) utilising an internal or external optical switch having one MPO
interface. Multimode measurements are made with an 850 nm source because transceivers
used for parallel optics applications having an MPO interface only operate at 850 nm; 1 300 nm
measurements are optional. Single-mode measurements are made with a 1 310 nm and/or
1 550 nm source because transceivers used for parallel optics applications having an MPO
interface operate at these wavelengths. This document does not include descriptions of cabling
that is not exclusively MPO to MPO.
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 (all parts), Safety of laser products
IEC 61280-1-3, Fibre optic communication subsystem test procedures – Part 1-3: General
communication subsystems – Central wavelength and spectral width measurement
IEC 61280-4-1:2019, Fibre-optic communication subsystem test procedures – Part 4-1:
Installed cabling plant – Multimode attenuation measurement
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 61746-1, Calibration of optical time-domain reflectometers (OTDR) – Part 1: OTDR for
single mode fibres
– 10 – IEC 61280-4-5:2020 © IEC 2020
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:
• 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
adapter
female-part of a connector in which one or two plugs are inserted and aligned
[SOURCE: IEC TR 61931:1998, 2.6.4]
3.1.2
alternative test method
ATM
test method for measuring a given characteristic in a manner consistent with the definition of
this characteristic, and giving results which are reproducible and relatable to the reference test
method and to practical use
[SOURCE: IEC TR 61931:1998, 2,8.2, modified – The alternative term "practical test method
(for optical fibres)" has been removed.]
3.1.3
attenuation
A
reduction of optical power induced by transmission through a medium such as cabling, given
as A:
A = 10 log (P /P )
10 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.
3.1.4
bi-directional measurement
two measurements of the same optical fibre made by launching light into opposite ends of that
fibre
3.1.5
channel
end-to-end transmission path connecting any two pieces of application-specific equipment
[SOURCE: ISO/IEC 11801-1:2017, 3.1.26]

3.1.6
configuration
form or arrangements of parts or elements such as terminations, connections and splices
3.1.7
connector
component normally attached to an optical cable or piece of apparatus for the purpose of
providing frequent optical interconnection/disconnection of optical fibres or cables
[SOURCE: IEC TR 61931:1998, 2.6.1, modified – The words in brackets "optical" and "fibre"
have been omitted from the term.]
3.1.8
encircled flux
EF
fraction of cumulative near-field power to total output power as a function of radial distance
from the optical centre of the core
[SOURCE: IEC TR 62614-2:2015, 3.3, modified – The words "radial-weighted" have been
deleted from the definition.]
3.1.9
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
3.1.10
low attenuation grade
connector and plug whose attenuation of a connection formed by mating two such assemblies
is lower and more repeatable than a "standard grade" termination (grade B in this document)
Note 1 to entry: An adapter required to assure the reduced attenuation can be considered to be part of the low
attenuation grade where required by the test configuration.
3.1.11
measurement bias
estimate of a systematic measurement error
Note 1 to entry: A systematic error is a component of measurement error that in repeated measurements remains
constant or varies in a predictable manner.
[SOURCE: ISO/IEC Guide 99:2007, 2.18, modified – Note 1 to entry has been added.]
3.1.12
MPO connector
multi-fibre component consisting of pinned or unpinned plug and mating adapter, normally
attached to an optical fibre cable, for the purpose of providing high density termination
capability, and frequent interconnection or disconnection
Note 1 to entry: See IEC 61754-7 (all parts) for description.
3.1.13
optical switch
passive component processing one or more ports which selectively transmits, redirects or
blocks optical power in an optical fibre transmission line
[SOURCE: IEC 60876-1:2014, 3.2.1]

– 12 – IEC 61280-4-5:2020 © IEC 2020
3.1.14
optical time domain reflectometer
OTDR
test system consisting of an optical time-domain reflectometer used to characterize and
measure the attenuation of installed cabling plant and specific elements within that cabling plant
3.1.15
plug
male-type part of a connector
[SOURCE: IEC TR 61931:1998, 2.6.2]
3.1.16
polarity
means of positioning optical fibres between MPO plugs to ensure a specific connectivity or
mapping of the cabling
3.1.17
reference plane
theoretical plane without thickness or tolerances
Note 1 to entry: The reference plane is used to define spaces in mechanical structures.
[SOURCE: IEC 60050-581:2008, 581-25-30]
3.1.18
reference test method
RTM
test method for measuring a given characteristic strictly according to the definition of this
characteristic, and giving results which are accurate, reproducible and relatable to practical use
[SOURCE: IEC TR 61931:1998, 2.8.1, modified – The words in brackets "for optical fibres" have
been omitted from the term.]
3.1.19
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 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.
3.2 Graphical symbols
Graphical symbols for different connection options, which have been adapted from
IEC TR 61282-15 and IEC 61280-4-1, and illustrate plug variability, are shown in Figure 1 a) to
h). Refer to IEC TR 61930 for other graphical symbols used within this document.
NOTE Low attenuation MPO plugs are terminated on test cords but not marked or shaded differently in the graphical
symbols or in testing examples within this document.

a) Plug assembly
b) MPO adapter c) Plug-adapter assembly

d) Cassette e) Breakout cable
f) Optical switch
g) Light source with MPO port h) Power meter with MPO port

Key
a single-fibre socket d MPO plug assembly
b single-fibre plug LS light source
c MPO adapter/socket PM power meter

NOTE In the figures above, the MPO plugs and jacks are shown generically, neither as pinned nor unpinned, and
neither as key-up nor key-down, for simplicity.
Figure 1 – Connector and apparatus symbols
In the figures that illustrate the measurement configurations in Annexes A through C, the cabling
under test is illustrated by a loop and connectors as shown in Figure 2. It can contain additional
splices and connectors. For purposes of measuring the attenuation of this cabling, the
attenuation associated with the near and far end connectors are considered separately from
the cabling itself.
In Figure 2, the cabling is shown with adapters pre-attached.

– 14 – IEC 61280-4-5:2020 © IEC 2020

Figure 2 – Symbol for cabling under test
3.3 Abbreviated terms
APC angled physical contact (description of plug polish)
ATM alternative test method
BIMMF bend insensitive multimode fibre
EF encircled flux
ELED edge emitting LED
LED light emitting diode
LSA least squares approximation
LSPM light source power meter
MPO multiple-fibre push on
OSW optical switch
OTDR optical time domain reflectometer
PC physical contact (description of plug polish)
PM power meter
RMS root mean square
RTM reference test method
4 Test methods
4.1 General
Five test methods are designated. The five test methods use MPO test cords to interface to the
cabling plant and are designated as follows:
• one-cord method (Annex A);
• three-cord method (Annex B);
• adapter-cord method (Annex
...

IEC 61280-4-5 ®
Edition 1.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre-optic communication subsystem test procedures –
Part 4-5: Installed cabling plant – Attenuation measurement of MPO terminated
fibre optic cabling plant using test equipment with MPO interfaces

Procédures d'essai des sous-systèmes de télécommunication fibroniques –
Partie 4-5: Installation câblée – Mesurage de l’affaiblissement de l’installation
câblée à fibres optiques à terminaisons MPO utilisant un équipement d’essai
avec interfaces MPO
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IEC 61280-4-5 ®
Edition 1.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre-optic communication subsystem test procedures –

Part 4-5: Installed cabling plant – Attenuation measurement of MPO terminated

fibre optic cabling plant using test equipment with MPO interfaces

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

Partie 4-5: Installation câblée – Mesurage de l’affaiblissement de l’installation

câblée à fibres optiques à terminaisons MPO utilisant un équipement d’essai

avec interfaces MPO
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.01 ISBN 978-2-8322-9165-8

– 2 – IEC 61280-4-5:2020 © IEC 2020
CONTENTS
FOREWORD . 7
1 Scope . 9
2 Normative references . 9
3 Terms, definitions, graphical symbols and abbreviated terms. 10
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 . 16
5.1 General . 16
5.2 Sources of significant uncertainties . 16
5.3 Consideration of the PM . 17
5.4 Consideration of test cord connector grade . 17
5.5 Typical uncertainty values for multimode testing . 17
5.6 Typical uncertainty values for single-mode testing . 19
6 Apparatus . 20
6.1 General . 20
6.2 Light source . 20
6.2.1 General . 20
6.2.2 Stability . 20
6.2.3 Spectral characteristics (LSPM measurement) . 21
6.3 Launch cord . 21
6.4 Receive or tail cord . 22
6.5 Substitution cord . 22
6.6 Adapter cord . 23
6.7 Power meter – LSPM methods only. 23
6.8 OTDR apparatus . 24
6.9 Connector end face cleaning and inspection equipment . 24
6.10 Adapters . 24
7 Procedures . 24
7.1 General . 24
7.2 Common procedures . 25
7.2.1 Care of the test cords . 25
7.2.2 Take reference measurements. 25
7.2.3 Inspect and clean the ends of the optical fibres in the cabling . 25
7.2.4 Take the measurements . 25
7.2.5 Make the calculations . 25
7.2.6 Multi-fibre and bi-directional testing . 25
7.3 Calibration . 26
7.4 Safety . 26
8 Calculations . 26
9 Documentation . 26
9.1 Information for each test . 26
9.2 Information to be available . 26

Annex A (normative) One-cord method . 27
A.1 Applicability of the test method . 27
A.2 Apparatus . 27
A.3 Procedure for unpinned to unpinned cabling with unpinned power meter . 27
A.4 Procedure for unpinned to pinned cabling with unpinned power meter . 28
A.5 Procedure for pinned to pinned cabling with pinned power meter . 29
A.6 Procedure for unpinned to unpinned cabling with pinned power meter and
gender-neutral test cord . 30
A.7 Calculation . 31
A.8 Components of reported attenuation . 31
Annex B (normative) Three-cord method . 32
B.1 Applicability of the test method . 32
B.2 Apparatus . 32
B.3 Procedure for unpinned to unpinned cabling . 32
B.4 Procedure for unpinned to pinned cabling . 33
B.5 Procedure for pinned to pinned cabling . 34
B.6 Procedure, channel test (general) . 35
B.7 Calculations . 36
B.8 Components of reported attenuation . 36
Annex C (normative) Adapter-cord method . 37
C.1 Applicability of the test method . 37
C.2 Apparatus . 37
C.3 Procedure for unpinned to unpinned cabling with pinned power meter . 37
C.4 Procedure for unpinned to pinned cabling with pinned power meter . 38
C.5 Procedure for pinned to unpinned cabling with unpinned power meter . 39
C.6 Procedure for pinned to pinned cabling with unpinned power meter . 40
C.7 Calculations . 41
C.8 Components of reported attenuation . 42
Annex D (normative) Equipment cord method . 43
D.1 Applicability of the test method . 43
D.2 Apparatus . 43
D.3 Procedure . 43
D.4 Calculation . 44
D.5 Components of reported attenuation . 44
D.6 Typical uncertainty values . 45
Annex E (normative) Optical time domain reflectometer . 46
E.1 Applicability of the test method . 46
E.2 Apparatus . 46
E.2.1 General . 46
E.2.2 OTDR . 46
E.2.3 Test cords . 47
E.3 Procedure (test method) . 47
E.4 Calculation . 48
E.4.1 General . 48
E.4.2 Connection location . 48
E.4.3 Definition of the power levels F and F . 49
1 2
E.4.4 Alternative calculation. 50
E.5 OTDR uncertainties . 52

– 4 – IEC 61280-4-5:2020 © IEC 2020
Annex F (normative) Requirements for the multimode source characteristics . 53
Annex G (informative) OTDR configuration information . 54
G.1 General . 54
G.2 Other measurement configurations . 54
G.2.1 General . 54
G.2.2 Measurement with low return loss connectors or short length cabling . 54
G.2.3 Measurement with APC connectors . 56
Annex H (informative) Test cord, breakout cord, and cassette attenuation verification . 58
H.1 General . 58
H.2 Apparatus . 58
H.3 General procedure . 58
H.3.1 Overview . 58
H.3.2 Test cord verification . 59
H.3.3 Cassette and breakout cord verification . 60
H.4 Test cord verification prior to cabling measurement . 61
H.4.1 General . 61
H.4.2 Procedure for unpinned to unpinned cabling measurement . 61
H.4.3 Procedure for unpinned to pinned cabling measurement . 62
H.4.4 Procedure for pinned to pinned cabling measurement . 63
Annex I (normative) On the use of low attenuation grade test cords . 66
I.1 General . 66
I.2 Practical configurations and assumptions. 66
I.2.1 Component specifications . 66
I.2.2 Conventions . 67
I.2.3 Reference planes . 67
I.3 Impact of using low attenuation grade test cords for recommended LSPM
methods . 68
I.4 Examples for LSPM measurements . 68
I.4.1 Example 1: Configuration Au-u, 1-C method (Annex A) . 68
I.4.2 Example 2: Configuration Du-u, EC method (Annex D) . 69
I.5 Impact of using reference grade test cords for different configurations using
the OTDR test method . 69
I.5.1 Cabling configurations Au-u, Ap-u and Ap-p . 69
I.5.2 Cabling configuration Du-u . 70
Bibliography . 72

Figure 1 – Connector and apparatus symbols . 13
Figure 2 – Symbol for cabling under test . 14
Figure 3 – OTDR schematic with external optical switch . 24
Figure A.1 – Reference measurement for unpinned to unpinned cabling using unpinned
power meter . 28
Figure A.2 – Test measurement for unpinned to unpinned cabling using unpinned
power meter . 28
Figure A.3 – Reference measurement for unpinned to pinned cabling using unpinned
power meter . 29
Figure A.4 – Test measurement for unpinned to pinned cabling using unpinned power
meter . 29
Figure A.5 – Reference measurement for pinned to pinned cabling using pinned power
meter . 30

Figure A.6 – Test measurement for pinned to pinned cabling using pinned power meter . 30
Figure A.7 – Reference measurement for unpinned to unpinned cabling using pinned
power meter . 31
Figure A.8 – Test measurement for unpinned to unpinned cabling (gender-neutral TC1)
using pinned power meter . 31
Figure B.1 – Reference measurement for unpinned to unpinned cabling using pinned
power meter . 33
Figure B.2 – Test measurement for unpinned to unpinned cabling using pinned power
meter . 33
Figure B.3 – Reference measurement for unpinned to pinned cabling using pinned
power meter . 34
Figure B.4 – Test measurement for unpinned to pinned cabling using pinned power
meter . 34
Figure B.5 – Reference measurement for pinned to pinned cabling using unpinned
power meter . 35
Figure B.6 – Test measurement for pinned to pinned cabling using unpinned power
meter . 35
Figure B.7 – Reference measurement for channel test using unpinned power meter . 36
Figure B.8 – Test measurement for channel test using unpinned power meter . 36
Figure C.1 – Reference measurement for unpinned to unpinned cabling using pinned
power meter . 38
Figure C.2 – Test measurement for unpinned to unpinned cabling using pinned power
meter . 38
Figure C.3 – Reference measurement for unpinned to pinned cabling using pinned
power meter . 39
Figure C.4 – Test measurement for unpinned to pinned cabling using pinned power
meter . 39
Figure C.5 – Reference measurement for unpinned to pinned cabling using unpinned
power meter . 40
Figure C.6 – Test measurement for unpinned to pinned cabling using unpinned power
meter . 40
Figure C.7 – Reference measurement for unpinned to pinned cabling using unpinned
power meter . 41
Figure C.8 – Test measurement for unpinned to pinned cabling using unpinned power
meter . 41
Figure D.1 – Reference measurement using pinned power meter . 44
Figure D.2 – Test measurement using pinned power meter . 44
Figure E.1 – OTDR method . 48
Figure E.2 – Location of the ports of the cabling under test . 49
Figure E.3 – Graphic construction of F and F . 50
1 2
Figure E.4 – Graphic construction of F , F , F and F . 51
1 11 12 2
Figure G.1 – Attenuation measurement with low return loss connectors . 55
Figure G.2 – Attenuation measurement of a short length cabling. 56
Figure G.3 – Attenuation measurement with APC MPO connections . 57
Figure H.1 – Obtaining reference power level P . 59
Figure H.2 – Obtaining power level P . 59
Figure H.3 – Obtaining reference power level P . 60
– 6 – IEC 61280-4-5:2020 © IEC 2020
Figure H.4 – Obtaining power level P . 60
Figure H.5 – Test measurement for unpinned to unpinned cabling . 61
Figure H.6 – Step 1: obtaining reference power level P . 61
Figure H.7 – Step 2: verification cords, obtaining power level P . 62
Figure H.8 – Test measurement for unpinned to pinned cabling . 62
Figure H.9 – Step 1: obtaining reference power level P . 63
Figure H.10 – Step 2: obtaining power level P . 63
Figure H.11 – Test measurement for pinned to pinned cabling . 63
Figure H.12 – Step 1: obtaining reference power level P . 64
Figure H.13 – Step 2: verification of cords, obtaining power level P . 64
Figure H.14 – Step 3: verification of receive cord, obtaining power level P . 65
Figure I.1 – Cabling configurations Au-u, Ap-u and Ap-p tested with OTDR method . 69
Figure I.2 – Cabling configuration Du-u tested with OTDR method . 71

Table 1 – Cabling configurations . 16
Table 2 – Test methods and configurations . 16
Table 3 – Measurements bias related to test cord connector grade . 17
Table 4 – Uncertainty for a given attenuation at 850 nm using same photodetector . 18
Table 5 – Uncertainty for a given attenuation at 850 nm using different photodetectors . 19
Table 6 – Uncertainty for a given attenuation at 1 310 nm using same photodetector . 19
Table 7 – Uncertainty for a given attenuation at 1 310 nm using different
photodetectors . 20
Table 8 – Spectral requirements . 21
Table D.1 – Uncertainty for a given attenuation when equipment cord method is used . 45
Table I.1 – Measurement bias adjustment when using low attenuation grade test cords . 68
Table I.2 – Acceptance figure adjustment using low attenuation grade test cords –
OTDR method . 70

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

Part 4-5: Installed cabling plant –
Attenuation measurement of MPO terminated fibre
optic cabling plant using test equipment with MPO interfaces

FOREWORD
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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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61280-4-5 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
The text of this International Standard is based on the following documents:
FDIS Report on voting
86C/1669/FDIS 86C/1679/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.
A list of all the parts in the IEC 61280 series, under the general title Fibre-optic communication
subsystem test procedures, can be found on the IEC website.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 8 – IEC 61280-4-5:2020 © IEC 2020
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.

FIBRE-OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 4-5: Installed cabling plant –
Attenuation measurement of MPO terminated fibre
optic cabling plant using test equipment with MPO interfaces

1 Scope
This part of IEC 61280 is applicable to the measurement of attenuation and determination of
polarity and length of installed multimode and single-mode optical fibre cabling plant, terminated
with MPO connectors, using test equipment having an MPO interface. This cabling plant can
include multimode or single-mode 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.
In this document, the optical fibres that are addressed include sub-categories A1-OMx, where
x = 2, 3, 4 and 5 (50/125 μm) multimode optical fibres, as specified in IEC 60793-2-10, and
category B-652 and B-657 (9/125 μm) single-mode optical fibres, as specified in
IEC 60793-2-50. The attenuation measurements of the other multimode and single-mode
categories can also be made using a light source and power meter (LSPM) or optical time
domain reflectometer (OTDR) utilising an internal or external optical switch having one MPO
interface. Multimode measurements are made with an 850 nm source because transceivers
used for parallel optics applications having an MPO interface only operate at 850 nm; 1 300 nm
measurements are optional. Single-mode measurements are made with a 1 310 nm and/or
1 550 nm source because transceivers used for parallel optics applications having an MPO
interface operate at these wavelengths. This document does not include descriptions of cabling
that is not exclusively MPO to MPO.
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 (all parts), Safety of laser products
IEC 61280-1-3, Fibre optic communication subsystem test procedures – Part 1-3: General
communication subsystems – Central wavelength and spectral width measurement
IEC 61280-4-1:2019, Fibre-optic communication subsystem test procedures – Part 4-1:
Installed cabling plant – Multimode attenuation measurement
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 61746-1, Calibration of optical time-domain reflectometers (OTDR) – Part 1: OTDR for
single mode fibres
– 10 – IEC 61280-4-5:2020 © IEC 2020
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:
• 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
adapter
female-part of a connector in which one or two plugs are inserted and aligned
[SOURCE: IEC TR 61931:1998, 2.6.4]
3.1.2
alternative test method
ATM
test method for measuring a given characteristic in a manner consistent with the definition of
this characteristic, and giving results which are reproducible and relatable to the reference test
method and to practical use
[SOURCE: IEC TR 61931:1998, 2,8.2, modified – The alternative term "practical test method
(for optical fibres)" has been removed.]
3.1.3
attenuation
A
reduction of optical power induced by transmission through a medium such as cabling, given
as A:
A = 10 log (P /P )
10 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.
3.1.4
bi-directional measurement
two measurements of the same optical fibre made by launching light into opposite ends of that
fibre
3.1.5
channel
end-to-end transmission path connecting any two pieces of application-specific equipment
[SOURCE: ISO/IEC 11801-1:2017, 3.1.26]

3.1.6
configuration
form or arrangements of parts or elements such as terminations, connections and splices
3.1.7
connector
component normally attached to an optical cable or piece of apparatus for the purpose of
providing frequent optical interconnection/disconnection of optical fibres or cables
[SOURCE: IEC TR 61931:1998, 2.6.1, modified – The words in brackets "optical" and "fibre"
have been omitted from the term.]
3.1.8
encircled flux
EF
fraction of cumulative near-field power to total output power as a function of radial distance
from the optical centre of the core
[SOURCE: IEC TR 62614-2:2015, 3.3, modified – The words "radial-weighted" have been
deleted from the definition.]
3.1.9
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
3.1.10
low attenuation grade
connector and plug whose attenuation of a connection formed by mating two such assemblies
is lower and more repeatable than a "standard grade" termination (grade B in this document)
Note 1 to entry: An adapter required to assure the reduced attenuation can be considered to be part of the low
attenuation grade where required by the test configuration.
3.1.11
measurement bias
estimate of a systematic measurement error
Note 1 to entry: A systematic error is a component of measurement error that in repeated measurements remains
constant or varies in a predictable manner.
[SOURCE: ISO/IEC Guide 99:2007, 2.18, modified – Note 1 to entry has been added.]
3.1.12
MPO connector
multi-fibre component consisting of pinned or unpinned plug and mating adapter, normally
attached to an optical fibre cable, for the purpose of providing high density termination
capability, and frequent interconnection or disconnection
Note 1 to entry: See IEC 61754-7 (all parts) for description.
3.1.13
optical switch
passive component processing one or more ports which selectively transmits, redirects or
blocks optical power in an optical fibre transmission line
[SOURCE: IEC 60876-1:2014, 3.2.1]

– 12 – IEC 61280-4-5:2020 © IEC 2020
3.1.14
optical time domain reflectometer
OTDR
test system consisting of an optical time-domain reflectometer used to characterize and
measure the attenuation of installed cabling plant and specific elements within that cabling plant
3.1.15
plug
male-type part of a connector
[SOURCE: IEC TR 61931:1998, 2.6.2]
3.1.16
polarity
means of positioning optical fibres between MPO plugs to ensure a specific connectivity or
mapping of the cabling
3.1.17
reference plane
theoretical plane without thickness or tolerances
Note 1 to entry: The reference plane is used to define spaces in mechanical structures.
[SOURCE: IEC 60050-581:2008, 581-25-30]
3.1.18
reference test method
RTM
test method for measuring a given characteristic strictly according to the definition of this
characteristic, and giving results which are accurate, reproducible and relatable to practical use
[SOURCE: IEC TR 61931:1998, 2.8.1, modified – The words in brackets "for optical fibres" have
been omitted from the term.]
3.1.19
test cord
terminated optical fibre cord used to connect the optical source or detector to the cabling, or to
provide suitable in
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