I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n

ITU-T E.164
TELECOMMUNICATION Supplement 6
STANDARDIZATION SECTOR
OF ITU (03/2012)

SERIES E: OVERALL NETWORK OPERATION,

TELEPHONE SERVICE, SERVICE OPERATION AND
HUMAN FACTORS
International operation – Numbering plan of the
international telephone service

The international public telecommunication numbering

plan
Supplement 6: Guidelines for identifying and selecting
globally harmonized numbers

Recommendation ITU-T E.164 – Supplement 6

 ITU-T E-SERIES RECOMMENDATIONS
OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN
FACTORS

INTERNATIONAL OPERATION
Definitions E.100–E.103
General provisions concerning Administrations E.104–E.119
General provisions concerning users E.120–E.139
Operation of international telephone services E.140–E.159
Numbering plan of the international telephone service E.160–E.169
International routing plan E.170–E.179
Tones in national signalling systems E.180–E.189
Numbering plan of the international telephone service E.190–E.199
Maritime mobile service and public land mobile service E.200–E.229
OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE
INTERNATIONAL TELEPHONE SERVICE
Charging in the international telephone service E.230–E.249
Measuring and recording call durations for accounting purposes E.260–E.269
UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-
TELEPHONY APPLICATIONS
General E.300–E.319
Phototelegraphy E.320–E.329
ISDN PROVISIONS CONCERNING USERS E.330–E.349
INTERNATIONAL ROUTING PLAN E.350–E.399
NETWORK MANAGEMENT
International service statistics E.400–E.404
International network management E.405–E.419
Checking the quality of the international telephone service E.420–E.489
TRAFFIC ENGINEERING
Measurement and recording of traffic E.490–E.505
Forecasting of traffic E.506–E.509
Determination of the number of circuits in manual operation E.510–E.519
Determination of the number of circuits in automatic and semi-automatic operation E.520–E.539
Grade of service E.540–E.599
Definitions E.600–E.649
Traffic engineering for IP-networks E.650–E.699
ISDN traffic engineering E.700–E.749
Mobile network traffic engineering E.750–E.799
QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES
AND DEPENDABILITY PLANNING
Terms and definitions related to the quality of telecommunication services E.800–E.809
Models for telecommunication services E.810–E.844
Objectives for quality of service and related concepts of telecommunication services E.845–E.859
Use of quality of service objectives for planning of telecommunication networks E.860–E.879
Field data collection and evaluation on the performance of equipment, networks and services E.880–E.899
OTHER E.900–E.999
INTERNATIONAL OPERATION
Numbering plan of the international telephone service E.1100–E.1199
NETWORK MANAGEMENT
International network management E.4100–E.4199

For further details, please refer to the list of ITU-T Recommendations.

Recommendation ITU-T E.164

The international public telecommunication numbering plan

Supplement 6

Guidelines for identifying and selecting globally harmonized numbers

Summary
Supplement 6 to Recommendation ITU-T E.164 outlines the benefits of globally harmonized
numbers (GHNs), and provides guidelines for the possible selection of the same number in every
national numbering plan in order to achieve the "same number – same service" concept, whenever
deemed appropriate.
Some major requirements to be taken into account when establishing GHNs are also stated.

History
Edition Recommendation Approval Study Group
1.0 ITU-T E.164/I.331 1984-10-19
2.0 ITU-T E.164/I.331/Q.11 bis 1988-11-25
3.0 ITU-T E.164/I.331 1991-08-23 II
4.0 ITU-T E.164 1997-05-30 2
4.1 ITU-T E.164 Suppl. 2 1998-11-13 2
4.2 ITU-T E.164 Suppl. 3 2002-05-16 2
4.3 ITU-T E.164 Suppl. 4 2003-05-02 2
4.4 ITU-T E.164 Suppl. 5 2008-05-15 2
5.0 ITU-T E.164 2005-02-24 2
6.0 ITU-T E.164 2010-11-18 2
6.1 ITU-T E.164 Suppl. 1 1998-03-09 2
6.1 ITU-T E.164 (2010) Amd. 1 2011-06-10 2
6.2 ITU-T E.164 Suppl. 2 2012-03-29 2
6.3 ITU-T E.164 Suppl. 3 2004-05-28 2
6.3 ITU-T E.164 Suppl. 2 2009-11-24 2
6.4 ITU-T E.164 Suppl. 3 Amd. 1 2009-11-24 2
6.5 ITU-T E.164 Suppl. 4 2004-05-28 2
6.6 ITU-T E.164 Suppl. 4 Amd. 1 2009-11-24 2
6.7 ITU-T E.164 Suppl. 5 2009-11-24 2
6.9 ITU-T E.164 Suppl. 6 2012-03-29 2

Rec. ITU-T E.164/Suppl.6 (03/2012) i

 FOREWORD
The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of
telecommunications, information and communication technologies (ICTs). The ITU Telecommunication
Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical,
operating and tariff questions and issuing Recommendations on them with a view to standardizing
telecommunications on a worldwide basis.
The World Telecommunication Standardization Assembly (WTSA), which meets every four years,
establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on
these topics.
The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
In some areas of information technology which fall within ITU-T's purview, the necessary standards are
prepared on a collaborative basis with ISO and IEC.

NOTE
In this publication, the expression "Administration" is used for conciseness to indicate both a
telecommunication administration and a recognized operating agency.
Compliance with this publication is voluntary. However, the publication may contain certain mandatory
provisions (to ensure, e.g., interoperability or applicability) and compliance with the publication is achieved
when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as
"must" and the negative equivalents are used to express requirements. The use of such words does not
suggest that compliance with the publication is required of any party.

INTELLECTUAL PROPERTY RIGHTS

ITU draws attention to the possibility that the practice or implementation of this publication may involve the
use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or
applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of
the publication development process.
As of the date of approval of this publication, ITU had not received notice of intellectual property, protected
by patents, which may be required to implement this publication. However, implementers are cautioned that
this may not represent the latest information and are therefore strongly urged to consult the TSB patent
database at http://www.itu.int/ITU-T/ipr/.

 ITU 2012
All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the
prior written permission of ITU.

ii Rec. ITU-T E.164/Suppl.6 (03/2012)

 Table of Contents
Page
1 Scope ............................................................................................................................ 1
2 References..................................................................................................................... 1
3 Definitions .................................................................................................................... 1
3.1 Term defined elsewhere ................................................................................. 1
3.2 Term defined in this supplement .................................................................... 2
4 Abbreviations and acronyms ........................................................................................ 2
5 Conventions .................................................................................................................. 2
6 Requirements for globally harmonized numbers .......................................................... 2
7 Further considerations for identifying and specifying a globally harmonized
number .......................................................................................................................... 3

Rec. ITU-T E.164/Suppl.6 (03/2012) iii

Introduction
The Telecommunication Standardization Bureau (TSB) of the International Telecommunication
Union (ITU) has allocated country codes to national administrations that, in turn, have managed the
national (significant) number (N(S)N) element as defined in [ITU-T E.164]. The N(S)N of every
national numbering plan is unique inside each country, and has evolved over a considerable period
of time. These N(S)Ns are currently administered in integrated numbering plans, and national
numbering plans, to reflect the legal, regulatory and commercial requirements. In a difficult
environment, the concept that elements of the national numbering plan could be harmonized to
some extent by adopting common principles for the design of numbering plans and choosing
identical codes for services of social values (SSV), is strongly encouraged.
It should be noted that numbering harmonization could also be useful for facilitating the mitigation
of the effects of climate change by collecting information and improving planning and response
mechanisms. This is of particular relevance in high-risk regions of the world that are challenged by
the severe consequences of such natural disasters as strong hurricanes, rising sea levels, etc.
Harmonization of telecommunication facilities to promote international communications is a
concept also considered within the purpose of the ITU and exists with the recognition of the
sovereign rights of Member States.
This supplement provides guidelines to identify and select numbers that might be useful if
harmonization of certain categories of services is desired.

iv Rec. ITU-T E.164/Suppl.6 (03/2012)

Recommendation ITU-T E.164

The international public telecommunication numbering plan

Supplement 6

Guidelines for identifying and selecting globally harmonized numbers

1 Scope
This supplement provides the basic concepts and advantages of services that are identified and
selected for the assignment of national numbers on a globally harmonized basis. Such number
assignment for services of social value (SSV) will be implemented to the extent permitted by
current national numbering plans.
Technology requirements are considered out of the scope of this supplement.

2 References
[ITU-T E.101] Recommendation ITU-T E.101 (2009), Definitions of terms used for
identifiers (names, numbers, addresses and other identifiers) for public
telecommunication services and networks.
[ITU T E.161.1] Recommendation ITU-T E.161.1 (2008), Guidelines to select Emergency
Number for public telecommunications networks.
[ITU T E.164 Sup.5] Recommendation ITU-T E.164 Supplement 5 (2008), Guidance with regard
to the selection of numbers for help lines for children.
[ITU-T E.1100] Recommendation ITU-T E.1100 (2009), Specification of an international
numbering resource for use in the provisioning of international help lines.
[ITU-T Q.1761] Recommendation ITU-T Q.1761 (2004), Principles and requirements for
convergence of fixed and existing IMT-2000 systems.
[ITU-T Q-Sup.47] ITU-T Q-Series Recommendations – Supplement 47 (2003), Emergency
services for IMT-2000 networks – Requirements for harmonization and
convergence.
[EU J-116] Official Journal of the European Union (2007), Commission decision
2007/116/EC.
<http://eur-lex.europa.eu/LexUriServ/site/en/oj/2007/l_049/l_04920070217en00300033.pdf>

3 Definitions

3.1 Term defined elsewhere

The following term defined elsewhere and used in this supplement is to be used within the context
of global number harmonization.
3.1.1 convergence [ITU-T Q.1761]: Coordinated evolution of formerly discrete networks toward
uniformity in support of services and applications.

Rec. ITU-T E.164/Suppl.6 (03/2012) 1

3.2 Term defined in this supplement
This supplement defines the following term:
3.2.1 services of social value: Services provided for the benefit of individuals to aid in
maintaining their well-being.
NOTE – This definition is based on the definition given for 'harmonized service of social value'
in [EU J-116].

4 Abbreviations and acronyms

This supplement uses the following abbreviations and acronyms:
GHN Globally Harmonized Number
HN Harmonized Number
SSV Service of Social Value

5 Conventions
There is no particular notation, style, presentation, or other conventions used within this
supplement.

6 Requirements for globally harmonized numbers

6.1 Process for identifying global harmonization of numbers
The definition of the SSV should be used as the basis for a circular to be sent to the Members of the
ITU, seeking their input on the following questions:
a) Does a service of social value, similar to that specified in the ITU, exist?
b) Are there plans to deploy such a service of social value?
c) What number(s) is/are currently being used to access such services of social value?
The responses to the circular letter should be analysed to identify which number, if any, might be
used in a further recommendation to identify a candidate for use as a national globally harmonized
number.
If such a number exists, then a further circular letter should be initiated to request Member States to
advise:
a) what, if any, issues exist in utilizing such a number in the future
a. by itself
b. in parallel with other existing national numbers for similar services.
b) under what circumstances use of the possible globally harmonized number would be
considered.
In the selection of the GHNs, consideration should be given to existing regional numbers and also
to numbers that are widespread in many countries across the world.
6.2 Process for specifying a globally harmonized number
If the results of the process for identifying a possible candidate for a national globally harmonized
number (GHN) (see clause 6.1) are positive, then such a number should be specified either in a new
Recommendation or in a supplement to [ITU-T E.164].
NOTE – If a Recommendation is to be used, then the text utilized should be in the same form as in
[ITU-T E.161.1].

2 Rec. ITU-T E.164/Suppl.6 (03/2012)

If global harmonization of a number is difficult in a given country due to the existence of an
equivalent commonly-used national number, the GHN could be implemented on a secondary basis.
However, any national implementation of GHNs is subject to availability and meeting the national
regulatory and legal requirements.
When considering the establishment of GHNs, it is advisable that the application of international
ITU-T E.164 numbers is also placed under review as an alternative option.

7 Further considerations for identifying and specifying a globally harmonized number

It is clear that mobility and mobile communications have a significant role in accessing
telecommunications and that such access is increased as more and more people are able to travel
with their own terminals, carrying the numbering information of their original network. In this
context, having different numbers/codes to provide the same service in different countries might be
very confusing. In addition, endeavours to harmonize numbers through technical solutions that
allow a national number from Country A to be routed to either the implemented harmonized
number deployed in Country B, or Country B's implementation of the number for a specific service
of social value, should only be done in line with national regulatory and legal requirements, based
upon a commercial implementation.
Access from fixed telephones to services of social value would benefit more from the selection and
deployment of a harmonized number. Unless and until similar technology, potentially on a
converged base to that of the mobile scenario, can be utilized in all telecommunication
environments, the use of a possible globally harmonized number should be considered, based on the
selection and specification criteria identified above.

Rec. ITU-T E.164/Suppl.6 (03/2012) 3

 SERIES OF ITU-T RECOMMENDATIONS

Series A Organization of the work of ITU-T

Series D General tariff principles

Series E Overall network operation, telephone service, service operation and human factors
Series F Non-telephone telecommunication services

Series G Transmission systems and media, digital systems and networks

Series H Audiovisual and multimedia systems

Series I Integrated services digital network

Series J Cable networks and transmission of television, sound programme and other multimedia signals

Series K Protection against interference

Series L Construction, installation and protection of cables and other elements of outside plant

Series M Telecommunication management, including TMN and network maintenance

Series N Maintenance: international sound programme and television transmission circuits

Series O Specifications of measuring equipment

Series P Terminals and subjective and objective assessment methods

Series Q Switching and signalling

Series R Telegraph transmission

Series S Telegraph services terminal equipment

Series T Terminals for telematic services

Series U Telegraph switching

Series V Data communication over the telephone network

Series X Data networks, open system communications and security

Series Y Global information infrastructure, Internet protocol aspects and next-generation networks

Series Z Languages and general software aspects for telecommunication systems

Printed in Switzerland
Geneva, 2012