SIST ETS 300 202 E1:2003

• Abstract:

  T/NA1(89)24

• 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 300 202 ed.1 (1994-12) - Integrated Services Digital Network (ISDN); Call Deflection (CD) supplementary service; Service description

SIST ETS 300 202 E1:2003 is a Slovenian standard from SIST that is identical to ETS 300 202 Edition 1 from ETSI. It specifies the stage 1 service description for the Call Deflection (CD) supplementary service in Integrated Services Digital Network (ISDN). The document is for public and private ISDN operators, network designers, and implementers who need to know when a served user may redirect an incoming call and how that choice affects the calling and deflected-to users.

What does SIST ETS 300 202 E1:2003 specify?

SIST ETS 300 202 E1:2003 specifies the user-facing behaviour of the CD supplementary service for pan-European ISDN. Clause 1 sets the scope from the user's point of view, while clauses 5 to 8 describe the service, the procedures, interworking, and interactions with other supplementary services.

The standard focuses on service description, not human-interface design, protocol design, or switching details. It also covers interworking requirements for private ISDNs with the public ISDN and the base functionality when the service is provided through a private ISDN.

Annex	What it covers
Annex A (informative)	Interaction between user-to-user signalling and CD after alerting

What are the key requirements of SIST ETS 300 202 E1:2003?

SIST ETS 300 202 E1:2003 defines when CD can be offered, how it is invoked, what different users are told, and how the service behaves when it meets other ISDN features. In practice, this gives service providers and equipment vendors the rules needed to present the service consistently and to handle redirection, notification, and rejection cases.

Provision, subscription, and invocation

• Clause 5 and 6.1 say CD is available to users on basic access or primary rate access, and it applies to all basic services subscribed to by the user. It can be provided either per ISDN number or across the whole access, which matters for how a provider structures subscriptions.
• The subscriber can choose notification settings for the calling user and whether the served user's ISDN number may be presented to the deflected-to user. These options determine what identity information is shared during redirection.
• Clause 6.2.3 limits invocation to the period before the connection is established, either in response to the offered call or while the served user is being informed of the incoming call. This means CD is a pre-connection decision, not a mid-call transfer.
• The request to invoke CD includes the ISDN number of the deflected-to user and, if needed, a subaddress. In practice, the serving network needs enough addressing data to set up the redirected call correctly.
• The network may limit the number of diversions in a call, with an upper limit of five, and every diversion type counts. This helps prevent long diversion chains and possible quality or routing problems.

User views and network behaviour

• Clause 6.2.3.1 describes the served user's view. The call is offered using basic call procedures, and the network either keeps the original call pending until the deflected-to user is reached or removes the call from the served user at once, depending on a network option. This affects whether the user sees the original call stay active during deflection.
• The served user may indicate whether their ISDN number can be presented to the deflected-to user. If supported, that indication can override the subscription setting for the specific call.
• Clause 6.2.3.2 states that the deflected-to user is told that CD has been invoked, and may also receive the served user's ISDN number depending on the subscription choice and any presentation restriction. For operators, this defines when identity information may accompany the redirected call.
• Clause 6.2.3.3 controls what the original calling user sees. The calling user may get no notification, a notification without the deflected-to number, or a notification with that number. Where the number is delivered, it is still subject to connected line identification restriction at the deflected-to side.

Exceptional cases, interworking, and service interaction

• Clause 6.3 covers failures and rejections. If the network cannot give a number that would normally be shown, it must indicate why no number is given. If the CD request cannot be accepted, the call continues at the served user and the reason for rejection is reported.
• If the redirected call to the deflected-to user cannot be completed, the call is either left with the served user or terminated back to a previous diverting user, depending on the network option and on whether earlier diversion has already taken place.
• Clause 7 allows interworking with non-ISDNs and private ISDNs. Once a call leaves the ISDN, later diversion behaviour and caller notifications are outside this standard. For private ISDNs, the standard keeps the total diversion limit in force across public and private networks.
• Clause 8 defines interactions with other supplementary services. Notable points are that call forwarding unconditional takes precedence over CD, call waiting can still coexist with CD, closed user group checking follows the original call into the diverted part, and subaddress information is not forwarded when a call is deflected.
• User-to-user signalling has detailed interaction rules in clause 8.17 and Annex A. Some requests are deflected with the call, while others can block CD depending on whether the service is required for the call to proceed.

What terms does SIST ETS 300 202 E1:2003 define?

• served user - The user to whom CD is provided and who decides whether to deflect the incoming call.
• user A - The calling user whose call may be deflected.
• user B - The served user in a call that is subject to CD.
• user C - The forwarded-to user in a call that is subject to CD.
• deflected-to user - The user to whom the call is redirected as a result of CD.
• diversion - The general class of call redirection, including forwarding and user-initiated deflection.
• basic call procedures - The normal procedures used to establish and terminate a basic telecommunication call.
• ISDN number - A number conforming to the ISDN numbering plan and structure.

Who uses SIST ETS 300 202 E1:2003?

SIST ETS 300 202 E1:2003 is used by public telecommunications operators, private ISDN operators, and service providers that offer call redirection features. It is also relevant to network engineers, switch and signalling implementers, and interoperability teams who need to design or verify how CD behaves in real calls.

Quality and product teams use it to check subscription handling, number presentation rules, rejection cases, and interaction with other supplementary services. Buyer and procurement teams can use it to confirm whether an ISDN service or platform supports user-controlled deflection rather than network-only forwarding.

What changed in SIST ETS 300 202 E1:2003 from the previous edition?

SIST ETS 300 202 E1:2003 is identical to ETS 300 202 Edition 1. The document history identifies the source as the first edition.

Which standards are used with SIST ETS 300 202 E1:2003?

Reference	What it contributes
CCITT Recommendation I.130	The three-level method for describing telecommunication services, including stage 1, stage 2, and stage 3
CCITT Recommendation I.112	ISDN vocabulary and core definitions used by this service description
CCITT Recommendation I.210	Principles for telecommunication services supported by an ISDN and how to describe them
CCITT Recommendation E.164	The ISDN numbering plan and the meaning of ISDN number, address, and subaddress
CCITT Recommendation Q.9	Switching and signalling vocabulary, including access types and related terms
ETS 300 206	The stage 2 aspects of the ISDN CD supplementary service
ETS 300 207	The stage 3 signalling protocol and switching functions for the ISDN CD supplementary service

What does the SIST ETS 300 202 E1:2003 document contain?

The document contains a foreword, scope, normative references, definitions, symbols and abbreviations, the service description, procedures, intercommunication considerations, and interactions with other supplementary services. Clause 6 sets out normal and exceptional procedures, including provision, invocation, and the handling of rejected or incomplete deflection attempts.

It also contains Table 1, which organizes the subscription options for notification and number presentation, and Annex A, which is an informative table on how user-to-user signalling interacts with CD after alerting. These parts are used by service designers and implementers when they need to map service options into operational behaviour.

The standard states that conformance is met through the related stage 3 standards for the relevant equipment field of application, and it therefore provides no test method of its own.

SLOVENSKI STANDARD
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Dopolnilna storitev: zavrnitev
klica s preusmeritvijo (CD) – Opis storitve
Integrated Services Digital Network (ISDN); Call Deflection (CD) supplementary service;
Service description
Ta slovenski standard je istoveten z: ETS 300 202 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 300 202
TELECOMMUNICATION December 1994
STANDARD
Source: ETSI TC-NA Reference: T/NA1(89)24
ICS: 33.080
ISDN, supplementary service
Key words:
Integrated Services Digital Network (ISDN);
Call Deflection (CD) 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 1994. All rights reserved.
New presentation - see History box

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ETS 300 202: December 1994
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 300 202: December 1994
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions.8
4 Symbols and abbreviations .9
5 Description .9
6 Procedures.9
6.1 Provision and withdrawal .9
6.2 Normal procedures .10
6.2.1 Activation, deactivation and registration.10
6.2.2 Erasure.10
6.2.3 Invocation and operation .10
6.2.3.1 Served user's view.10
6.2.3.2 Deflected-to user's view.11
6.2.3.3 Calling user's view .11
6.2.4 Interrogation .13
6.3 Exceptional procedures .13
6.3.1 Activation, deactivation and registration.13
6.3.2 Erasure.13
6.3.3 Invocation and operation .13
6.3.4 Interrogation .14
7 Intercommunication considerations.14
7.1 Interworking with non-ISDNs .14
7.2 Interworking with private ISDNs.15
8 Interaction with other supplementary services .15
8.1 Advice of charge services.15
8.1.1 Charging information at call set-up time.15
8.1.2 Charging information during the call.15
8.1.3 Charging information at the end of the call.16
8.2 Call waiting.16
8.3 Call hold .16
8.4 Explicit call transfer.16
8.5 Number identification services.16
8.5.1 Calling line identification presentation .16
8.5.2 Calling line identification restriction .16
8.5.3 Connected line identification presentation.17
8.5.4 Connected line identification restriction.17
8.6 Closed user group.17
8.7 Completion of calls to busy subscriber .17
8.8 Conference services .18
8.8.1 Conference call, add on .18
8.8.2 Meet-me conference .18
8.9 Direct dialling in.18
8.10 Diversion services.18
8.10.1 Call forwarding unconditional .18
8.10.2 Call forwarding busy.18
8.10.3 Call forwarding no reply.18
8.10.4 Call deflection.18

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ETS 300 202: December 1994
8.11 Freephone. 19
8.12 Malicious call identification. 19
8.13 Multiple subscriber number . 19
8.14 Subaddressing . 19
8.15 Terminal portability. 19
8.16 Three party service. 19
8.17 User-to-user signalling . 20
8.17.1 Request for the CD supplementary service in response to the offered call. 20
8.17.2 Request for the CD supplementary service during the period that the user
is being informed of the incoming call . 20
8.17.3 After deflection. 21
Annex A (informative): Interaction between user-to-user signalling and CD (after alerting) . 22
History. 23

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ETS 300 202: December 1994
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 Call Deflection (CD)
supplementary service. The stage 2 and stage 3 aspects are detailed in ETS 300 206 (1994) and
ETS 300 207 (1994), respectively.
Proposed transposition dates
Date of latest announcement of this ETS (doa): 31 March 1995
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 September 1995
Date of withdrawal of any conflicting National Standard (dow): 30 September 1995

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1 Scope
This standard defines the stage one of the Call Deflection (CD) 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 CD supplementary service enables the served user to respond to an incoming call by requesting
redirection of that call to another user. The CD supplementary service can only be invoked before the
connection is established by the served user, i.e. in response to the offered call, or during the period that
the served user is being informed of the call. The served user's ability to originate calls is unaffected by
the CD supplementary service.
The CD supplementary service is applicable to all circuit-switched telecommunication services.
This standard is applicable to the stage two and stage three standards for the ISDN CD 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 authorization
leaving freedom, or 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 characterization of
telecommunication services supported by an ISDN and network capabilities of
an ISDN".
[2] CCITT Recommendation I.112 (1988): "Vocabulary of terms for ISDNs".
[3] CCITT Recommendation I.210 (1988): "Principles of telecommunication
services supported by an ISDN and the means to describe them".
[4] CCITT Recommendation E.164 (1991): "Numbering plan for the ISDN era".
[5] CCITT Recommendation Q.9 (1988): "Vocabulary of switching and signalling
terms".
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3 Definitions
For the purposes of this standard, the following definitions apply:
Integrated Services Digital Network (ISDN): See CCITT Recommendation I.112 [2], § 2.3, definition
308.
(basic) service; telecommunications service: See CCITT Recommendation I.112 [2], § 2.2, definition
201.
served user: The user to whom the CD supplementary service is provided.
user A: The calling user in a call which is subject to diversion.
user B: The served user when a call (from user A) is subject to the CD supplementary service.
NOTE: In the context of multiple diversions, a suffix is used, e.g. 1, 2, . n, n+1, . m, to
denote the successive diverting users. For example, user B3 is also the diverted-to
user with respect to the diversion applied at user B2.
user C: The forwarded-to user in a call which is subject to the CD supplementary service. In the case of a
call which is subject to multiple diversions, user C is the deflected-to user with respect to the final call
deflection.
deflected-to user: A user to whom the call is redirected as a result of the CD supplementary service.
diverted-to user: A user to whom a call is redirected as a result of diversion.
supplementary service: See CCITT Recommendation I.210 [3], paragraph 2.4.
ISDN number: A number conforming to the numbering plan and structure specified in CCITT
Recommendation E.164 [4].
basic access: See CCITT Recommendation Q.9 [5], § 1, definition 1551.
primary rate access: See CCITT Recommendation Q.9 [5], § 1, definition 1552.
address: See CCITT Recommendation E.164 [4], § 12.
subaddress: See CCITT Recommendation E.164 [4], § 12.2.
(call) forwarding: A general term applied to any functionality whereby a call is redirected automatically by
the service provider to another user. The forms of forwarding are: unconditional, whereby all calls are
redirected; busy, whereby calls encountering busy are redirected; and, no reply, whereby calls which are
not answered within a time period are redirected.
diversion: A general term which includes all forms of forwarding, and includes deflection whereby calls
are redirected by the user instead of being answered.
basic call procedures: The procedures by which a call (as an instance of a basic telecommunication
service) is established and terminated.
diverting user: A user for whom the call is subjected to diversion.
multipoint access: See CCITT Recommendation I.112 [2], definition 422.

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4 Symbols and abbreviations
CD Call Deflection
ISDN Integrated Services Digital Network
PSTN Public Switched Telephone Network
5 Description
The CD supplementary service shall be available to users who are connected to the network via a basic
access or a primary rate access.
The CD supplementary service enables the served user to respond to an incoming call by requesting
redirection of that call to another user. The CD supplementary service can only be invoked before the
connection is established by the served user, i.e. in response to the offered call, or during the period that
the served user is being informed of the call. The served user's ability to originate calls is unaffected by
the CD supplementary service.
The maximum number of diversions permitted for each call is a service provider option with an upper limit
of five diversions. When counting the number of diversions, all types of diversion are included.
6 Procedures
6.1 Provision and withdrawal
The CD supplementary service shall be provided after prior arrangement with the service provider.
The CD supplementary service shall apply to all of the basic services subscribed to by the user.
As a service provider option, the CD supplementary service can be provided on a per ISDN number basis,
or the CD supplementary service can apply to the whole access. If a service provider offers both of these
options, then it shall be a subscription option to choose which of these options applies.
As a service provider option, the CD supplementary service can be offered with one or both of two
subscription options. If the CD supplementary service is provided on a per ISDN number basis, then these
options can apply separately to each ISDN number. For each subscription option, only one value can be
selected. Subscription options are summarized in table 1.
Table 1
Subscription options Value
Calling user receives notification -no
that the call has been deflected - yes, without the ISDN
number of the deflected-to
user
- yes, with the ISDN number of
the deflected-to user
The served user's ISDN number -no
can be presented to the deflected-to - yes
user
The CD supplementary service shall be withdrawn by the service provider upon request of the subscriber
or for service provider reasons.

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ETS 300 202: December 1994
6.2 Normal procedures
6.2.1 Activation, deactivation and registration
The CD supplementary service shall be activated on provision and deactivated on withdrawal.
The CD supplementary service requires no registration.
6.2.2 Erasure
Not applicable.
6.2.3 Invocation and operation
The maximum number of diversions for each call shall be limited. The maximum number of diversions is a
service provider option with an upper limit of five diversions for each call. When counting the number of
diversions, all types of diversions shall be included.
6.2.3.1 Served user's view
The call shall be offered to the served user by means of basic call procedures.
The CD supplementary service can be invoked on a call prior to the connection being established for the
call i.e. in response to the offered call, or during the period that the served user is being informed of the
call.
NOTE 1: This functionality may be performed at any time after the indication of the arrival of an
incoming call by means of an automatic mechanism programmed into the user's
equipment, or it may be performed by the user in person after the user has been
informed of the incoming call.
The request to invoke the CD supplementary service shall contain the ISDN number of the deflected-to
user, accompanied by a subaddress if required for additional identification of the deflected-to user.
The served user can also include an indication that the served user's ISDN number can, or cannot, be
presented to the deflected-to user. As a service provider option, if this indication is included in the request
for the CD supplementary service then, for this call, it shall override the value of the corresponding
subscription option given in table 1. If the service provider does not support this option and the indication
is included, it shall be ignored.
On a multipoint access, the acceptance of a request for the CD supplementary service from a particular
terminal shall be dependent on the reaction of other terminals to the same call. Two cases can be
distinguished:
- a terminal requests the CD supplementary service immediately in response to a call request from
the network. In this case, the network shall process the request providing that the connection has
not already been established and no other terminal has already indicated that the user is being
informed of the call;
NOTE 2: It is the served user's responsibility to avoid contention.
NOTE 3: During an interim period some networks may give priority to responses from other
terminals, i.e. the request for the CD supplementary service will not be processed if, as
part of basic call procedures, another terminal responds by establishing the connection
or indicating that the user is being informed of the call.

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- the CD supplementary service is requested whilst the user is being informed of the call. In this case,
the network shall process the request providing that no other terminal has already established the
connection and the call has not been terminated in the meantime.
If a request to invoke the CD supplementary service is received whilst another request is being processed,
then this subsequent request shall be rejected.
If the request to invoke the CD supplementary service can be accepted, then the CD supplementary
service shall be invoked. The network shall set up a call to the deflected-to user indicated by the served
user. According to a network option, one of the following shall occur:
a) the served user shall be informed that the CD supplementary service is being invoked. The call to
the served user shall be retained until the network receives an indication that the deflected-to user
is being informed of the call, or that the connection is established at the deflected-to user,
whereupon the call shall be removed from the served user. If, on a multipoint access, another
terminal requests the establishment of the connection prior to the removal of the call, then the
connection shall be established and the deflection ceased; or
b) the call shall be removed from the served user when the CD supplementary service is invoked and
the served user shall be informed that the call has been removed due to the CD supplementary
service.
6.2.3.2 Deflected-to user's view
The deflected-to user shall receive an indication that the CD supplementary service has been invoked on
the call. Depending on the value of one of the served user's subscription options, possibly overridden by
an indication in the request for the CD supplementary service, the deflected-to user can also receive the
ISDN number of the served user.
If multiple diversions have occurred, then the deflected-to user can also be given the originally called
user's ISDN number provided that the presentation has been permitted by the diversion service invoked
for the originally called user. When multiple diversions occur the reason for diversion given to the
diverted-to user shall indicate the last type of diversion (i.e. the invocation of the CD supplementary
service).
6.2.3.3 Calling user's view
Depending on the value of the served user's subscription option "calling user receives notification that the
call has been deflected", user A can be given an indication that the call is being deflected. In that case,
this information shall be given when the network originates the call to the deflected-to user. Depending on
the value of this subscription option, user A can also be given the ISDN number of the deflected-to user.
When calls are diverted once, i.e. due to a single invocation of the CD supplementary s
...