SIST EN 301 104 V1.1.1:2003

Human Factors (HF); Human factors requirements for a European Telephony Numbering Space (ETNS)

The identification of the Human Factors issues in the creation of a European Numbering Space and the creation of recommendations for addressing those issues. The recommendations will be targeted at those who need to implement and test a European Numbering Space. Issues that have been identified during the production of TR101056 include: difficulties with long telephone numbers, effects related to number portability, the way in which European Numbers can be identified and how users can identify their costs, the effect of call delays, linguistic difficulties with European services, and the need for usability testing.

Človeški dejavniki (HF) – Zahteve zaradi človeških dejavnikov za evropski telefonski številski prostor (ETNS)

General Information

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.040.01 - Telecommunication systems in general
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI EN 301 104 V1.1.1 (1998-10) - Human Factors (HF); Human factors requirements for a European Telephony Numbering Space (ETNS)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 301 104 V1.1.1:2003
01-december-2003
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Human Factors (HF); Human factors requirements for a European Telephony Numbering
Space (ETNS)
Ta slovenski standard je istoveten z: EN 301 104 Version 1.1.1
ICS:
33.040.01 Telekomunikacijski sistemi Telecommunication systems
na splošno in general
SIST EN 301 104 V1.1.1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 301 104 V1.1.1:2003

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SIST EN 301 104 V1.1.1:2003
EN 301 104 V1.1.1 (1998-10)
European Standard (Telecommunications series)
Human Factors (HF);
Human factors requirements for a
European Telephony Numbering Space (ETNS)

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SIST EN 301 104 V1.1.1:2003
2 EN 301 104 V1.1.1 (1998-10)
Reference
REN/HF-00009 (a8000ico.PDF)
Keywords
addressing, CLIP, HF, migration, portability,
service, UNI, UR
ETSI
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Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1998.
All rights reserved.
ETSI

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SIST EN 301 104 V1.1.1:2003
3 EN 301 104 V1.1.1 (1998-10)
Contents
Intellectual Property Rights.4
Foreword .4
1 Scope.5
2 References.5
3 Definitions and abbreviations .6
3.1 Definitions . 6
3.2 Abbreviations. 6
4 Structure of ETNS service numbers.7
4.1 Numbering scheme . 7
4.1.1 European Number (EN) . 7
4.1.2 European Service Identity (ESI). 7
4.1.3 European Subscriber Number (ESN) . 8
5 Number formatting.8
5.1 User dialling difficulties. 8
5.2 Number presentation. 8
6 Migration to a global numbering scheme.9
7 Number portability issues .10
7.1 Consistent charging. 10
7.2 No change for calling party. 10
7.3 ETNS subscriber privacy . 10
8 Identification of ETNS services.10
9 Identification of charging.11
10 Routeing delays.11
11 Handling languages within ETNS services.12
12 Usability testing .13
13 Compliance .14
History.16
ETSI

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SIST EN 301 104 V1.1.1:2003
4 EN 301 104 V1.1.1 (1998-10)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect
of ETSI standards", which is available free of charge from the ETSI Secretariat. Latest updates are available on the
ETSI Web server (http://www.etsi.org/ipr).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in SR 000 314 (or the updates on the ETSI Web server)
which are, or may be, or may become, essential to the present document.
Foreword
This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Human Factors
(HF).
The intended users of the present document include:
Table 1: Intended users and potential benefits
User ES used for Potential Benefit
1 Service designers Development of the structure and Establish a minimum level of usability
presentation of ETNS services through adherence to the requirements in
the present document.
2 ETNS service providers To establish a basis for ensuring that Minimum level of usability of services
their services will meet the needs of
their users
3 User groups To identify problems within ETNS Increased awareness by user groups of the
services value of a minimum level of usability
through adherence to human factors
requirements
4 ETSI Technical Bodies Development of ETNS standards Minimum level of usability of services by
that support users’ minimum needs ensuring that basic user needs are met
National transposition dates
Date of adoption of this EN: 23 October 1998
Date of latest announcement of this EN (doa): 31 January 1999
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 July 1999
Date of withdrawal of any conflicting National Standard (dow): 31 July 1999
ETSI

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SIST EN 301 104 V1.1.1:2003
5 EN 301 104 V1.1.1 (1998-10)
1 Scope
The present document specifies the Human Factors (HF) requirements related to all aspects of a European Telephony
Numbering Space (ETNS). It describes the requirements to be met jointly by the ETNS service provider and the
network operator enabling access to the ETNS service.
The present document applies to any ETNS service provided within an ETNS scheme based upon a European Country
Code (CC) and provided for access from public and private telecommunications networks.
It covers those aspects of ETNS services that would be of importance to the users of those services and to other
telephony users who may be affected by the introduction of an ETNS. Requirements cover:
- the formatting of the written presentation of ETNS numbers to enable users:
- to identify an ETNS service;
- to minimize dialling errors caused by difficulties in memorizing long digit strings;
- rules for migrating from an ETNS Service to a Global Service that will minimize difficulties for users;
- rules that ensure that called users receive appropriate Calling Line Identity (CLI) information when called from a
European Number (EN);
- rules that ensure calling users are still able to determine call charges after a EN has been ported to a new
provider;
- rules that ensure the minimization of user difficulties caused by call delays;
- rules to overcome the potential linguistic difficulties associated with ETNS services.
Mobility aspects of an ETNS are outside the scope of the present document. Only those aspects of an ETNS to which
specific requirements can be attached are covered in the present document. Other Human Factors aspects of an ETNS
are presented in TR 101 056 [1].
2 References
References may be made to:
a) specific versions of publications (identified by date of publication, edition number, version number, etc.), in
which case, subsequent revisions to the referenced document do not apply; or
b) all versions up to and including the identified version (identified by "up to and including" before the version
identity); or
c) all versions subsequent to and including the identified version (identified by "onwards" following the version
identity); or
d) publications without mention of a specific version, in which case the latest version applies.
A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same
number.
[1] TR 101 056: "Human Factors (HF); European Numbering Task Force (ENTF); Human Factors
aspects of the European Telephony Numbering Space (ETNS)".
[2] ITU-T Recommendation E.721: "Network grade of service parameters and target values for
circuit-switched services in the evolving ISDN".
[3] ITU-T Recommendation E.164: "The international public telecommunication numbering plan".
[4] ITU-T Recommendation E.123: "Notation for national and international telephone numbers".
[5] TR 101 073: "Number portability for pan-European services".
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SIST EN 301 104 V1.1.1:2003
6 EN 301 104 V1.1.1 (1998-10)
[6] TR 101 041 Parts 1 and 2: "Human Factors (HF): European harmonization of network generated
tones".
[7] COM(96) 590 Commission of the European Communities: "Towards a European Numbering
Environment: Green Paper on a Numbering Policy for Telecommunications Services in Europe".
[8] D. MacDonald, S. Archambault, "Using Customer Expectation in Planning the Intelligent
Network", The Fundamental Role of Teletraffic in the Evolution of Telecommunications
Networks, Proc. of 14th ITC, Antibes Juan-les-Pins, France, June 1994, pp. 95-104.
[9] ETR 116: "Human Factors (HF); Human factors guidelines for ISDN Terminal equipment design".
[10] ETR 329: "Human Factors (HF); Guidelines for procedures and announcements in Stored Voice
Services (SVS) and Universal Personal Telecommunication (UPT)".
[11] ETO 96 09 94 04: "Second Interim Report on Numbering related to the topic of user-friendliness".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following definitions apply:
post-dialling delay: for ISDN calls the post-dialling delay is the post-selection delay (en-bloc sending). For non-ISDN
calls the post-dialling delay is the time interval from the caller pressing the last dialled digit or pressing a key to send all
the digits of the called number until a call disposition message or signal is received by the calling terminal.
Post-Selection Delay (EN-Bloc Sending): the time interval from the instant the first bit of the initial SETUP message
containing all the selection digits is passed by the calling terminal to the access signalling system until the last bit of the
first message indicating call disposition is received by the calling terminal (ALERTING message in case of successful
call) (see ITU-T Recommendation E.721 [2]).
ETNS service: a service that has been assigned a European Service Identity (ESI).
ETNS service provider: an entity that provides one or more ETNS service(s) to its ETNS Subscribers on a contractual
basis.
ETNS subscriber: an entity that requests a European Number from a ETNS Service Provider in order to offer access
from a Calling Party to an ETNS service.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
CC Country Code
CEC Commission of the European Communities
CLI Calling Line Identity
ECC European Country Code
ECNA European Corporate Network Access
EN European Number
ENTF European Numbering Task Force
ESC European Service Code
ESI European Service Identity
ESN European Subscriber Number
ETNS European Telephony Numbering Space
ETO European Telecommunications Office
GSN Global Service Number
HF Human Factors
ITU-T International Telecommunications Union - Telecommunications (formerly CCITT)
ETSI

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SIST EN 301 104 V1.1.1:2003
7 EN 301 104 V1.1.1 (1998-10)
4 Structure of ETNS service numbers
4.1 Numbering scheme
The ETNS numbering scheme upon which the requirements in the present document are based assumes the use of a
specific Country Code (CC) assigned to Europe (CC-388).
Subclauses 4.1.1 to 4.1.3 describe this scheme.
4.1.1 European Number (EN)
To implement the European Country Code (CC) scheme the allocation of a specific CC is required. The European CC is
used to identify a set of ETNS services provided in two or more ETNS countries, instead of designating a specific
country. Figure 1 describes the structure of the ETNS number.
European Number EN
ESI
Generic structure of EN ESN
EN
ECC ESC ESN
Figure 1: European Number Structure
The structure of the EN should not preclude evolution towards a global numbering scheme on a per service basis where
this is a requirement.
ETNS shall be designed to have a minimum of 100 services and a potential of 10 million subscribers per service if
required.
The total length of the number shall not exceed 15 digits.
4.1.2 European Service Identity (ESI)
An ESI is assigned to a service or a family of services in some specific cases.
An ESI shall begin with the CC allocated to the ETNS. The length of the ESC can vary between 1 and 4 digits.
Examples of ESIs are:
- 388 3;
- 388 25;
- 388 326;
- 388 5432.
The length of the ESIs can either vary with a minimum length of 4 digits (e.g. 388 2) and a maximum of 7
(e.g. (388 2345)). In this scheme, there is no problem to find a hundred ESCs.
There shall not be any indication of an ETNS service provider in the ESI.
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8 EN 301 104 V1.1.1 (1998-10)
4.1.3 European Subscriber Number (ESN)
The structure and length of the ESN depends on the service, mostly according to the number of ETNS service providers
and to the number of expected subscribers.
Initially the number's length is fixed for any given service, the use of variable length numbers is for further study.
To reach the goal of 10 million subscribers, the ESN shall be at least 7 digits long.
For some services the ESN is not required e.g. access to information services or services that require 2-stage dialling.
An ESN can be either structured or unstructured. In an unstructured number, there is no meaningful information
embedded in the number. In a structured number, the first part of the number, called the domain entity, uniquely
identifies one ETNS subscriber. By looking at the domain entity, the user would be able to determine who the ETNS
subscriber is.
5 Number formatting
5.1 User dialling difficulties
Some of the schemes for moving from ETNS services to global services may result in longer numbers and these will
reach the ITU-T limit of 15 digits (see ITU-T Recommendation E.164 [3]). When the need to allocate codes to
corporate networks is taken into account, it is likely that European corporate network numbers will be longer than other
ETNS numbers and, in some European countries, longer than existing national numbers and longer than existing
corporate network numbers. This increased number length, to 14 or 15 digits, will mean that corporate network numbers
will be amongst the most difficult for users to remember and to dial. The corporate network number length problem will
only apply to people outside a corporate network trying to access someone within it. For internal calls within a corporate
network, people will only have to dial abbreviated codes, and these need be no longer than codes used in any similarly
sized corporate network not using ETNS numbers.
There is very good evidence that dialling accuracy will decrease significantly with number length (see TR 101 056 [1]).
As numbers increase in length and become difficult to memorize the incidence of dialling errors or of call set-up being
terminated by inter-digit time-outs is likely to increase as users repeatedly refer back to printed or written telephone
numbers.
5.2 Number presentation
For printed material, the issue of how a number should be presented is addressed in ITU-T Recommendation E.123 [4].
The Recommendations in this clause are based on the principles contained in ITU-T Recommendation E.123 [4].
If someone had to dial a telephone number such as:
(00)388522759763456
(the maximum length of a corporate network number if the 15th digit eventually came into use) they would find it
impossible without having the number broken down into smaller groups. To aid the user, telephone numbers are usually
broken down into logically significant groups of digits such as the European corporate network access code (including
the international prefix), the corporate network identity and finally the number identifying the specific addressable entity
e.g.:
[phone] 52273456.
This grouping is used both when numbers are written or spoken. It has a clear benefit in aiding the user to read the digits
from the page or store them in memory. In addition, where these groups of digits are very familiar e.g. the international
prefix and, in the future perhaps, the European corporate network access code, they may be treated as discrete "chunks"
rather than individual digits by the user's short-term memory. It is also common practice to further divide logical blocks
of the number into shorter groups:
e.g. 52273456 might be presented as 52 27 34 56.
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This again can improve the ease with which the number can be read from the page. In some cultures, users have become
accustomed to remembering groups such as "double two", which would be memorized as a single chunk, and grouping
into regular groups of two digits may interfere with this, e.g. in grouping a number as 52 27 the user is unlikely to spot
the repeated digit 2 which might be more easily memorized as "five double-two seven".
When the ESN is structured, the domain identity should be shown as a contiguous group of digits and the remaining
digits (the domain specific number) should be separated from the domain identity and formatted according to the
standard rules for the formatting of ESNs.
In order to minimize user difficulties and possible errors, the requirements for presenting public or Corporate Network
ETNS numbers in written or spoken form are:
1) When presenting ENs the international dialling prefix and the European CC or European Corporate Network
Access Identity, they shall be grouped together as a single block of digits without using the brackets commonly
placed around the international prefix e.g. 00388 or 003885. This will emphasize that ETNS services shall
always be dialled using the international dialling prefix. This presentation that also omits brackets around the
international prefix may also reduce user concerns that the ETNS call will automatically be charged at a
potentially high international charging rate.
2) The European Service Code (ESC) or Corporate Network Identity shall be presented as a single block of digits
e.g. 234 or 5234.
3) Where the ESN is structured, the domain identity shall be presented as a contiguous group of digits separated
from the ESC or Corporate Network Identity and from the domain specific number.
4) The ESN or domain specific number shall be divided into groups of 2, 3 or 4 digits, e.g. 123 4567 or 12 34 56 78
except where the conditions of point 4 below can be shown to apply. The exact combination of these digit groups
will be determined according to the number of digits remaining. This structuring shall be considered as part of
the allocation of the ESI.
NOTE: Where an ETNS service subscriber wishes to use a memorable but non-standard structuring of the
subscriber number, the ETNS service subscriber may, during the allocation process, propose that this
structuring is used.
6 Migration to a global numbering scheme
It is possible that a service implemented as an ETNS service may at a later date be migrated to a global service
numbering scheme. There are two options for how such a migration could be implemented.
The first option is for the whole ETNS number to be added after the new global service CC. In subclause 4.1.3, it is
shown that the number length can be constrained to 12 digits and still meet the requirements of up to 100 services and
up to 10 million subscribers. If the maximum number length for an ETNS number were restricted to 12 digits this would
still lead to a situation where the number length would be increased by 3 digits to a minimum of 15 digits. Such a long
number (as a minimum) is clearly not very desirable for service users e.g. "388 5 service number" would change to
"nnn†388 5 service number".
The second option is to embed the European Service Number (ESN) in the Global Service Number (GSN) and add it
after the global service CC. This assumes that the GSN is longer than the ESN. An additional digit might need to be
added in front of the ESN to form the GSN but this would still mean that the number length could be kept to a 12 or
13 digits (minimum).
Both options retain significant parts of the original ETNS number, which will aid users. Both schemes introduce a new
global service CC to the user, which will be something new and unfamiliar for them to learn. The second option is far
better from a Human Factors (HF) perspective because of the much shorter number length, with the advantages outlined
in subclause 5.1.
The difficulties of migrating corporate network numbers to a global scheme are the same as for public network numbers.
They will, however, be at the longest end of the range of number lengths and hence they are likely to be the most
difficult for users to deal with if migrated to a global numbering scheme.
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SIST EN 301 104 V1.1.1:2003
10 EN 301 104 V1.1.1 (1998-10)
7 Number portability issues
Number portability for ETNS services has been defined as a feature that allows a customer of an ETNS service to
change the provider of this specific service retaining the same ETNS number (see TR 101 073 [5]). This definition does
not allow changes between different ETNS services whilst retaining the same number.
7.1 Consistent charging
It is an important HF requirement that the calling party's ability to determine the charge of a call should not be affected
by a change of ETNS service provider for an ETNS number. The following option shall be used to meet the consistent
charging requirement:
- the mechanisms for apportioning costs between the various parties (calling party, customers, ETNS Service
Providers, network providers, etc.) shall result in the charge to the calling party remaining the same no matter
which ETNS service provider is used by the called party.
7.2 No change for calling party
Given the fact that charging to the calling party will not be affected by the change of ETNS Service Provider, the calling
party does not need to be aware that the change has taken place. This viewpoint avoids valueless information being
communicated to the calling party resulting in the overuse of the limited means of user feedback (e.g. tones, messages,
etc.).
Calling parties, when calling numbers that has been moved to an alternative ETNS service provider, should not
encounter any changes that adversely affect the user interface that they experiences. Examples of such changes include:
- a restriction or limitation of supplementary services;
- confusion or lack of comprehension of tones or announcements (see TR 101 041 Parts 1 and 2 [6]).
A change of ETNS service provider shall not cause a reduction in the usability of the ETNS service. The ETNS
subscriber shall be responsible for demonstrating that no reduction in usability has taken place.
7.3 ETNS subscriber privacy
For privacy reasons, the ETNS subscriber may also require that a change of ETNS Service Provider supporting its
ETNS number will not be identified by the calling party. Requirements in subclauses 7.1 and 7.2 satisfy this
requirement.
8 Identification of ETNS services
In ETNS services where the ETNS subscriber is the called party, the European CC acts as a very clear signal to the
calling party of that service that the number containing it is an ETNS service.
In ETNS services where the calling party originates a call from an EN (e.g. European Personal Services), it is important
that the CLI correctly identifies the ETNS service. This leads to the following requirement:
- CLI information presented to the called party shall be the calling party's ETNS Number and not the telephone
number of the location from which the telephone call originates.
CLI for ENs may be significantly different from CLIs for national calls. The issues surrounding such differences needs
to be understood and require additional detailed study with respect to signalling, number presentation, CPE etc., prior to
any service offering being made COM(96) 590 [7].
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11 EN 301 104 V1.1.1 (1998-10)
Emergency services need to be able to identify the physical location of the calling party. This leads to the following
requirement:
- Emergency services shall be provided with a means to determine the physical location of the calling party. In
many cases, access to the geographic telephone number of the calling party may be an appropriate means of
obtaining this information.
9 Identification of charging
With the increasing diversity of ETNS services and special charging regimes on offer, it is getting increasingly difficult
for calling parties to identify what the call charging rate will be from studying the number. In the longer term there may
need to be different ways of indicating call charging rates to calling parties, but for now it is still possible to make some
use of the number structure.
At present there is one fairly universal rule, that any calls preceded by an international prefix will be charged at a
different and usually higher international charge rate. ETNS numbers will always need an international prefix. However,
different services will be charged at potentially very different rates - some possibly as high or higher than international
rates and some significantly lower. If calling parties are able to identify:
a) that the service is an ETNS service;
b) what type of service it is;
they may be able to infer the appropriate charge rate. If calling parties mis-identify the call as an ordinary international
call, they will almost certainly be incorrect in their inferred charge. It is thus important that the calling party can clearly
identify the type of service and that the service is an ETNS service. Various numbering options that improve the clear
identification of ETNS services have been discussed in subclause 5.2.
10 Routeing delays
A very diverse range of routeing options may exist for ETNS services. These are too diverse to list in the present
document, but it is possible to identify two usability criteria that can be used in evaluating the merits of the different
routeing options. These usability criteria are:
a) Call set-up times should not be made unduly long as a result of very complex routeing methods;
b) The variability of call set-up times should not be too great.
Many of the routeing options involve passing the numbering information from one country to another and they may also
involve several stages of number translation. Although modern digital telecommunications systems typically perform
routeing operations very quickly, a succession of these may still take some time. These delays wo
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