SIST ETS 300 367 E1:2003

• Abstract:

  T/NA1(89)22.1

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• 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 ETS 300 367 ed.1 (1995-03) - Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary service; Service description

SIST ETS 300 367 E1:2003 is the Slovenian publication of ETS 300 367 Edition 1 for the Integrated Services Digital Network (ISDN) Explicit Call Transfer (ECT) supplementary service. It is an ETSI stage 1 service description, written from the user’s point of view, and it explains how ECT lets one user turn two existing calls into a single call between the other two users.

This standard is aimed at telecommunications operators and implementers who need the service behavior, call-transfer rules, and interworking conditions for ISDN ECT.

What does SIST ETS 300 367 E1:2003 specify?

SIST ETS 300 367 E1:2003 specifies the stage 1 description of the ECT supplementary service for public ISDN, plus the interworking requirements for private ISDNs and the base functionality when the service is offered through a private ISDN. It is organized into clauses on scope, normative references, definitions, symbols and abbreviations, description, procedures, intercommunication, and interactions with other supplementary services, followed by informative Annex A.

Annex	What it covers
A (informative)	Management of active and held calls when a user controls more than one call, including switching, disconnecting, setting up another call, and invoking ECT or related multi-party services

Clause 8 gives the interaction rules with services such as advice of charge, call hold, number identification, closed user group, conference services, diversion services, freephone, malicious call identification, three party, and user-to-user signalling. The standard also says that conformance is met through the relevant stage 3 standards, so it does not provide a test method.

What are the key requirements of SIST ETS 300 367 E1:2003?

How ECT works in practice

SIST ETS 300 367 E1:2003 defines ECT as a service where user A has two calls - one active and one held - and the network connects the other two parties, user B and user C, into one call. One practical result is that user A leaves the connection, while B and C continue the call with each other.

The standard allows both incoming and outgoing calls to be involved, and it applies to circuit-switched basic telecommunication services. In practice, this means ECT is not limited to one call direction and is intended for the standard circuit-switched ISDN environment.

When transfer may happen

SIST ETS 300 367 E1:2003 requires that one of the two calls already has an established connection before transfer. The other call may also have an established connection, or, as a service provider option, it may still be in the state where user C is being informed of the call.

If that option is supported, the transfer can occur before user C answers, and user B is later connected when user C does answer. For implementers, this means the network must preserve the call state and the later transition must still lead to a valid transfer.

What happens after transfer

SIST ETS 300 367 E1:2003 requires the two calls to be removed from user A’s access and transformed into a call between user B and user C. The service provider must inform both users that the transfer occurred and indicate whether the other side was already connected or was still being informed of the call.

The standard also controls number presentation. Subject to the relevant restriction rules, user B’s ISDN number is shown to user C, and user C’s ISDN number is shown to user B. It also allows subaddresses to be passed in defined cases, which matters for terminals and networks that use subaddress information.

When requests are rejected

SIST ETS 300 367 E1:2003 requires rejection if the user is not subscribed to ECT or if the network cannot connect user B and user C. It also allows rejection, as a network option, if the resulting connection would contain no user able to terminate the call.

For operators, this means ECT is not a blind transfer feature: the network may refuse the request when the call cannot be handed over safely or meaningfully.

Interworking and other services

SIST ETS 300 367 E1:2003 covers interworking with non-ISDNs and with private ISDNs. For private ISDNs, it refers to ETS 300 345 for general interworking requirements, and it specifies how indications and numbers are forwarded to the remote network.

Clause 8 also sets interaction rules with other supplementary services. Examples include call hold, calling line and connected line identification restrictions, closed user group, conference call add-on, meet-me conference, freephone, malicious call identification, three party, and user-to-user signalling. In practice, this is the part to check when ECT must coexist with other services already enabled on the call.

What terms does SIST ETS 300 367 E1:2003 define?

• ECT - Explicit Call Transfer, the supplementary service that turns two calls involving user A into one call between the other users.
• ISDN - Integrated Services Digital Network, the network type covered by this standard.
• User A - the served user to whom ECT is provided and who controls the two calls.
• User B - the other user in one of user A’s calls, treated as already connected on that call.
• User C - the other user in the second call controlled by user A.
• Held call - a call on which call hold is currently operating.
• Active call - a call on which call hold is not currently operating.
• Service provider - the entity that offers subscription to ECT.

Who uses SIST ETS 300 367 E1:2003?

SIST ETS 300 367 E1:2003 is used by public telecommunications operators, network operators, and service providers that offer ISDN supplementary services. It is also used by designers and implementers of switching and signalling systems who need to support ECT, especially where private ISDNs interwork with public ISDNs.

Equipment vendors and test, quality, and service teams use it to understand the intended service behavior before moving to the stage 2 and stage 3 specifications.

What changed in SIST ETS 300 367 E1:2003 from the previous edition?

SIST ETS 300 367 E1:2003 is the Slovenian publication of ETS 300 367 Edition 1.

Which standards are used with SIST ETS 300 367 E1:2003?

• CCITT Recommendation I.130 - provides the three-stage method used to describe ISDN supplementary services.
• ITU-T Recommendation I.112 - provides ISDN vocabulary and definitions used in the standard.
• CCITT Recommendation E.164 - provides the ISDN numbering plan and the basis for ISDN numbers and subaddresses.
• ITU-T Recommendation I.210 - provides the principles and descriptive means for supplementary services.
• ETS 300 345 - gives the general interworking requirements between public ISDNs and private ISDNs.
• ETS 300 368 - the stage 2 companion for ECT.
• ETS 300 369-1 and ETS 300 356-14 - the stage 3 companions for ECT.

What does the SIST ETS 300 367 E1:2003 document contain?

The document contains the service description, call procedures, intercommunication rules, and interaction rules for ECT in ISDN. Clause 6 covers provision, withdrawal, normal procedures, and exceptional procedures, while Clause 7 covers interworking with non-ISDNs and private ISDNs.

Clause 8 gives the service interactions that matter most in deployment, especially identity presentation, diversion, conferencing, freephone, malicious call identification, and user-to-user signalling. Annex A gives practical guidance for users who are managing one active call and one or more held calls.

SLOVENSKI STANDARD
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Dopolnilna storitev:
nedvoumna predaja klica (ECT) – Opis storitve
Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary
service; Service description
Ta slovenski standard je istoveten z: ETS 300 367 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 367
TELECOMMUNICATION May 1995
STANDARD
Source: ETSI TC-NA Reference: T/NA1(89)22.1
ICS: 33.080
ISDN, supplementary service
Key words:
Integrated Services Digital Network (ISDN);
Explicit Call Transfer (ECT) supplementary service
Service description
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - [e-mail]
X.400: Internet:
Tel.: [phone] - Fax: [phone]
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 1995. All rights reserved.
New presentation - see History box

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ETS 300 367: May 1995
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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ETS 300 367: May 1995
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions.8
4 Symbols and abbreviations .8
5 Description .9
6 Procedures.9
6.1 Provision and withdrawal .9
6.2 Normal procedures .9
6.2.1 Activation, deactivation and registration.9
6.2.2 Erasure.9
6.2.3 Invocation and operation .9
6.2.4 Interrogation .10
6.3 Exceptional procedures .10
6.3.1 Activation, deactivation and registration.10
6.3.2 Erasure.10
6.3.3 Invocation and operation .11
6.3.4 Interrogation .11
7 Intercommunication considerations.11
7.1 Interworking with non-ISDNs .11
7.2 Interworking with private ISDNs.12
8 Interaction with other supplementary services .12
8.1 Advice of charge services.12
8.1.1 Charging information at call set-up time.12
8.1.2 Charging information during the call.12
8.1.3 Charging information at the end of the call.12
8.2 Call waiting.12
8.3 Call hold .13
8.4 Explicit call transfer.13
8.5 Number identification services.13
8.5.1 Calling line identification presentation .13
8.5.2 Calling line identification restriction .13
8.5.3 Connected line identification presentation.13
8.5.4 Connected line identification restriction.13
8.6 Closed user group.14
8.7 Completion of calls to busy subscriber .14
8.8 Conference services .14
8.8.1 Conference call, add-on .14
8.8.2 Meet-me conference .14
8.9 Direct dialling in.14
8.10 Diversion services.14
8.10.1 Call forwarding unconditional .14
8.10.2 Call forwarding busy.14
8.10.3 Call forwarding no reply.14
8.10.4 Call deflection.15
8.11 Freephone.15
8.12 Malicious call identification.15
8.13 Multiple subscriber number.15

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ETS 300 367: May 1995
8.14 Subaddressing . 15
8.15 Terminal portability. 15
8.16 Three party. 15
8.17 User-to-user signalling . 16
Annex A (informative): Management of active and held calls . 17
A.1 Introduction. 17
A.2 Functionality available to the served user controlling more than one call. 17
History. 18

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ETS 300 367: May 1995
Foreword
This European Telecommunication Standard (ETS) has been produced by the Network Aspects (NA)
Technical Committee of the European Telecommunications Standards Institute (ETSI).
In accordance with CCITT Recommendation I.130 [1], the following three level structure is used to
describe the supplementary telecommunications services as provided by European public
telecommunications operators under the pan-European Integrated Services Digital Network (ISDN):
- Stage 1: is an overall service description, from the user's standpoint;
- Stage 2: identifies the functional capabilities and information flows needed to support the
service described in stage 1; and
- Stage 3: defines the signalling system protocols and switching functions needed to implement
the service described in stage 1.
This ETS details the stage 1 aspects (overall service description) for the Explicit Call Transfer (ECT)
supplementary service. The stage 2 aspects are detailed in ETS 300 368 (1995) and the stage 3 aspects
are detailed in ETS 300 369-1 (1995) and ETS 300 356-14 (1995).
Proposed transposition dates
Date of latest announcement of this ETS (doa): 31 August 1995
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 29 February 1996
Date of withdrawal of any conflicting National Standard (dow): 29 February 1996

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ETS 300 367: May 1995
1 Scope
This standard defines the stage one of the Explicit Call Transfer (ECT) supplementary service for the
pan-European Integrated Services Digital Network (ISDN) as provided by European public
telecommunications operators. Stage one is an overall service description from the user's point of view
(see CCITT Recommendation I.130 [1]), but does not deal with the details of the human interface itself.
This standard defines the interworking requirements of private ISDNs with the public ISDN.
In addition this standard specifies the base functionality where the service is provided to the user via a
private ISDN.
This standard does not specify the additional requirements where the service is provided to the user via a
telecommunications network that is not an ISDN but does include interworking requirements of other
networks with the public ISDN.
Interactions with supplementary services not listed in clause 8 are outside the scope of this standard.
Charging principles are outside the scope of this standard.
The ECT supplementary service enables a user who has two calls, each of which can be an incoming call
or an outgoing call, to connect together the other users in the two calls, into one call.
The ECT supplementary service is applicable to all circuit-switched basic telecommunication services.
This standard is applicable to the stage two and stage three standards for the ISDN ECT supplementary
service. The terms "stage two" and "stage three" are also defined in CCITT Recommendation I.130 [1].
Where the text indicates the status of a requirement, (i.e. as strict command or prohibition, as
authorisation leaving freedom, as a capability or possibility), this shall be reflected in the text of the
relevant stage two and stage three standards.
Furthermore, conformance to this standard is met by conforming to the stage three standards with the
field of application appropriate to the equipment being implemented. Therefore no method of testing is
provided for this standard.
2 Normative references
This standard incorporates, by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this standard only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
[1] CCITT Recommendation I.130 (1988): "Method for the characterisation of
telecommunication services supported by an ISDN and network capabilities of
an ISDN".
[2] ITU-T Recommendation I.112 (1993): "Vocabulary of terms for ISDNs".
[3] CCITT Recommendation E.164 (1991): "Numbering plan for the ISDN era".
[4] ITU-T Recommendation I.210 (1993): "Principles of telecommunication services
supported by an ISDN and the means to describe them".
[5] ETS 300 345: "Integrated Services Digital Network (ISDN); Interworking
between public ISDNs and private ISDNs for the provision of telecommunication
services; General aspects".
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ETS 300 367: May 1995
3 Definitions
For the purposes of this standard, the following definitions apply:
Integrated Services Digital Network (ISDN): see ITU-T Recommendation I.112 [2], § 2.3, definition 308.
Service; telecommunication service: see ITU-T Recommendation I.112 [2], § 2.2, definition 201.
Supplementary service: see ITU-T Recommendation I.210 [4], § 2.4.
ISDN number: a number conforming to the numbering plan and structure specified in CCITT
Recommendation E.164 [3].
User A: the user to whom the ECT supplementary service is provided.
User B: the other user in one of user A's calls. By convention, in this standard, it is considered that the
connection has been established on this call.
User C: the other user in another of user A's calls.
Network operator: the entity which provides the network operating elements and resources for the
execution of the ECT supplementary service.
Service provider: the entity which offers subscription to the ECT supplementary service. The network
operator may be the service provider.
Basic access: see ITU-T Recommendation I.112 [2], § 2.4, definition 425.
Primary rate access: see ITU-T Recommendation I.112 [2], § 2.4, definition 426.
Subaddress: see CCITT Recommendation E.164 [3], § 12.2.
Held call: a call on which the call hold supplementary service is currently in operation.
Active call: a call on which the call hold supplementary service is not currently in operation.
NOTE: In other contexts, an active call is a call on which the connection has already been
established. This is not the usage of this term for this standard.
4 Symbols and abbreviations
ECT Explicit Call Transfer
ISDN Integrated Services Digital Network

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5 Description
The ECT supplementary service enables a user (user A) to transform two of that user's calls (an active
call and a held call), each of which can be an incoming call or an outgoing call, into a new call between
user B and user C.
NOTE 1: Details of the management of active calls and held calls are given in annex A.
Prior to transfer, the connection shall have been established on the call between user A and user B. On
the call between user A and user C, either the connection shall have been established prior to transfer, or,
as a service provider option, transfer can occur while user C is being informed of the call (i.e. the
connection has not yet been established).
NOTE 2: Service providers may reject a request for the ECT supplementary service depending
on criteria outside the scope of this standard (e.g. for operational reasons under
certain circumstances). The associated procedures are outside the scope of this
standard.
The ECT supplementary service can be available to users who are connected to the network via a basic
access or a primary rate access.
6 Procedures
6.1 Provision and withdrawal
The ECT supplementary service shall be provided to the user after prior arrangement with the service
provider.
The ECT supplementary service shall be withdrawn by the service provider upon request of the subscriber
or for service provider reasons.
6.2 Normal procedures
6.2.1 Activation, deactivation and registration
Not applicable.
6.2.2 Erasure
Not applicable.
6.2.3 Invocation and operation
User A, who has two calls (one with user B and one with user C), each of which can be an incoming call or
an outgoing call, can request the invocation of the ECT supplementary service with respect to the two
calls.
NOTE 1: It is the responsibility of user A to ensure that the two calls are compatible.
NOTE 2: It is not relevant which call (between user A and user B or between user A and user C)
is a held call when the ECT supplementary service is invoked. For example, if user A
has a call on which the connection has been established, user A can put that call on
hold (by means of the call hold supplementary service) and then set up a second call.
After that, user A can switch between the two calls as appropriate (see annex A).
The connection shall have been established on one of the calls (referred to as the call between user A and
user B).
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ETS 300 367: May 1995
The ECT supplementary service can be invoked after the connection has been established on the call
between user A and user C, and in addition, as a service provider option, after user C has been informed
of the call (i.e. an outgoing call from user A to user C, where the connection has not yet been established).
On successful invocation of the ECT supplementary service, the two calls between user A and user B and
between user A and user C, shall be removed from user A's access and shall be transformed into a call
between user B and user C.
If the service provider option above is supported, then if user C is being informed of the call from user A at
the time of transfer, the call shall remain in this state at user C, and when the connection is established by
...