SIST ETS 300 183 E1:2003

• Abstract:

  T/NA1(89)25

• 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 300 183 ed.1 (1992-10) - Integrated Services Digital Network (ISDN); Conference call, add-on (CONF) supplementary service; Service description

SIST ETS 300 183 E1:2003 is the Slovenian adoption of ETS 300 183 Edition 1 from ETSI. It specifies the stage 1 service description for the Conference call, add-on (CONF) supplementary service in the pan-European Integrated Services Digital Network (ISDN). The document is aimed at people who need to understand how the service behaves from the user's point of view, especially service providers, network planners and implementers.

What does SIST ETS 300 183 E1:2003 specify?

SIST ETS 300 183 E1:2003 specifies the stage 1 description of the CONF supplementary service for public ISDNs. It explains the service from the user standpoint, defines the service behavior, and shows how it fits with private ISDNs and other supplementary services.

The standard is organized into clauses 1 to 8, followed by one informative annex:

Annex	What it covers
Annex A	Management of active and held calls

Clause 1 gives the scope, clause 2 lists normative references, clause 3 defines terms, clause 4 lists symbols and abbreviations, clause 5 describes the service, clause 6 sets out procedures, clause 7 covers intercommunication considerations, and clause 8 covers interaction with other supplementary services. Clause A.1 and A.2 explain what a user can do when more than one call is involved.

Clause 1 also states that the document is a stage 1 service description and that conformance is achieved through the corresponding stage 3 standard. In practice, that means this document tells you what the service must do, while the signaling and protocol details are handled elsewhere.

What are the key requirements of SIST ETS 300 183 E1:2003?

SIST ETS 300 183 E1:2003 describes how a user can start, manage and end a conference involving several users. The most important points are the service access rules, the conference control functions, the notification behavior, and the interactions with other ISDN services.

Service provision and invocation

Clause 6.1 says the CONF supplementary service is provided by prior arrangement with the service provider and withdrawn by request of the subscriber or for service-provider reasons. Clause 5 says the service applies to both basic access and primary rate access. In practice, a network operator needs to provision the service before a user can use it, and implementers need to support it on both access types.

Clause 6.2.3 allows the conference to be invoked from the idle state. As a network option, it can also be invoked from an existing active call. If the user does not indicate the number of parties, the network uses the maximum allowed value. This matters because the network must reserve enough conference resources before the conference can begin.

Starting a conference from an active call

Clause 6.2.3.2 describes the case where an existing call is connected into the conference. If the call was not held, the served user is connected to the conference; if the call was held, the conference is held by the served user. The other user in the call becomes a conferee and must be notified. For operators, this means the network has to preserve the state of the original call while moving it into conference handling.

Managing the conference

Clause 6.2.3.3 lists the main control actions available to the conference controller. The controller can hold their own connection, create a private communication with one party, terminate the whole conference, disconnect one party, add a conferee, isolate a conferee, and reattach an isolated conferee. If the controller creates a private communication, the selected party leaves the conference temporarily and the conference continues among the remaining parties. In practice, this gives the controller several ways to moderate or reorganize the call without ending it.

Clause 6.2.3.4 gives conferees a more limited set of actions: they can hold their own connection or release it. This matters because the controller has the main control role, while conferees can manage only their own participation.

Notification and rejection handling

Clause 6.2.3.5 requires participants to be informed when their call state changes. Other conferees are informed when a party is added, removed, isolated or reattached. The standard also says conferees are not informed when the controller holds or retrieves the whole conference. This is important for user experience and for terminal design, because call state changes need to be visible to the right people.

Clause 6.3.3 lists rejection cases such as lack of subscription, too many conferees, or lack of resources. If a conference manipulation request fails, the served user receives a rejection with the reason, and the user's calls remain in their previous state. That protects existing calls from being disturbed by a failed conference action.

Interworking and other services

Clause 7 allows conferees to belong to the PSTN or any other network that supports speech, and it covers interworking with private ISDNs. It also notes that quality can degrade when conferees are on different networks, for example because of delay or attenuation. For network planners, this means interworking is allowed, but quality and notification behavior may need attention.

Clause 8 describes interactions with other supplementary services, including advice of charge, call waiting, call hold, explicit call transfer, number identification services, closed user group, completion of calls to busy subscriber, conference services, diversion services, Freephone, malicious call identification, multiple subscriber number, subaddressing, terminal portability, three party, and user-to-user signalling. These interactions matter because a conference call does not operate alone - the network must keep the service behavior consistent when other services are active.

What terms does SIST ETS 300 183 E1:2003 define?

SIST ETS 300 183 E1:2003 defines the key roles and call states used in the service description.

• Integrated Services Digital Network (ISDN) - the network context for the service, with definitions taken from CCITT Recommendation I.112.
• CONF - short for Conference call, add-on, the supplementary service described in the standard.
• Served user - the user to whom the CONF supplementary service is provided.
• Conference controller - the served user who invokes CONF and controls adding and removing conferees.
• Conferee - any user in the conference other than the conference controller.
• Private communication - a separate communication between the conference controller and one other user, outside the main conference.
• Active call - a call whose connection has already been established.
• Idle state - the state where the user invokes CONF without an associated call.

Who uses SIST ETS 300 183 E1:2003?

SIST ETS 300 183 E1:2003 is used by public telecommunications operators, ISDN service designers, switching engineers and equipment implementers who need the service behavior defined at stage 1. It is also relevant to private ISDN operators because the standard covers interworking between private ISDNs and the public ISDN.

In practice, service providers use it to configure how conference calls are offered and controlled. Network and terminal engineers use it to understand what the user can do during a conference, what must happen when a call is added or removed, and how the service interacts with charging, transfer, identification and other supplementary services.

What changed in SIST ETS 300 183 E1:2003 from the previous edition?

SIST ETS 300 183 E1:2003 is identical to ETS 300 183 Edition 1. The history notes the first edition in October 1992.

Which standards are used with SIST ETS 300 183 E1:2003?

SIST ETS 300 183 E1:2003 cites these references and companion parts:

• CCITT Recommendation I.130 (1988) - gives the service characterization model used to distinguish stage 1, stage 2 and stage 3.
• CCITT Recommendation I.112 (1988) - provides ISDN vocabulary used for core terms such as ISDN and service.
• CCITT Recommendation I.210 (1988) - defines supplementary service principles and the way they are described.
• CCITT Recommendation Q.9 (1988) - provides switching and signaling vocabulary, including access terms.
• ETS 300 184 (1992) - gives the stage 2 aspects for the CONF supplementary service.
• ETS 300 185 (1992) - gives the stage 3 aspects for the CONF supplementary service.

What does the SIST ETS 300 183 E1:2003 document contain?

SIST ETS 300 183 E1:2003 contains a service description rather than a test method. Clause 5 explains what the CONF supplementary service does, clause 6 gives the procedures for provision, invocation, conference control and exceptional handling, and clause 7 addresses interworking with non-ISDNs and private ISDNs.

Clause 8 is the main interaction section. It describes how CONF behaves with advice of charge, call hold, explicit call transfer, number identification, closed user group, diversion services, terminal portability, three party and user-to-user signalling. Annex A then explains how a user manages active and held calls, including alternate use of calls, disconnecting calls, establishing another call, invoking explicit call transfer, starting three-way conversation and beginning CONF with an active call.

SLOVENSKI STANDARD
01-december-2003
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NRQIHUHQþQLNOLFSRVWRSQRY]SRVWDYOMDQMH&21)±2SLVVWRULWYH
Integrated Services Digital Network (ISDN); Conference call, add-on (CONF)
supplementary service; Service description
Ta slovenski standard je istoveten z: ETS 300 183 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 300 183
TELECOMMUNICATION October 1992
STANDARD
Source: ETSI TC-NA Reference: T/NA1(89)25
ICS: 33.080
ISDN, supplementary service
Key words:
Integrated Services Digital Network (ISDN);
Conference call, add-on (CONF) 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 1992. All rights reserved.
New presentation - see History box

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ETS 300 183: October 1992
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 300 183: October 1992
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions.8
4 Symbols and abbreviations .8
5 Description .8
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
6.2.3.1 Beginning the conference from the idle state .9
6.2.3.2 Beginning the conference from an active call.9
6.2.3.3 Managing the conference .10
6.2.3.4 Actions available to conferees.10
6.2.3.5 Notification of participants .11
6.2.4 Interrogation .11
6.3 Exceptional procedures .11
6.3.1 Activation, deactivation and registration.11
6.3.2 Erasure.11
6.3.3 Invocation and operation .11
6.3.4 Interrogation .11
7 Intercommunication considerations.12
7.1 Interworking with non ISDNs.12
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
8.1.1.1 Conference controller .12
8.1.1.2 Conferees .13
8.1.2 Charging information during the call.13
8.1.2.1 Conference controller .13
8.1.2.2 Conferees .14
8.1.3 Charging information at the end of a call.15
8.1.3.1 Conference controller .15
8.1.3.2 Conferees .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.16
8.5.4 Connected line identification restriction.16
8.6 Closed user group.17
8.7 Completion of calls to busy subscriber .17
8.8 Conference services .17

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ETS 300 183: October 1992
8.8.1 Conference call, add-on. 17
8.8.2 Meet-me conference. 17
8.9 Direct dialling in . 17
8.10 Diversion services . 17
8.10.1 Call forwarding unconditional. 17
8.10.2 Call forwarding busy . 17
8.10.3 Call forwarding no reply . 17
8.10.4 Call deflection . 17
8.11 Freephone. 18
8.12 Malicious call identification. 18
8.13 Multiple subscriber number . 18
8.14 Subaddressing . 18
8.15 Terminal portability. 18
8.16 Three party. 18
8.17 User-to-user signalling . 18
Annex A (informative): Management of active and held calls . 20
A.1 Introduction. 20
A.2 Functionality available to the served user controlling more than one call. 20
History. 21

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ETS 300 183: October 1992
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 standard details the stage 1 aspects (overall service description) for the Conference call, add-on
(CONF) supplementary service. The stage 2 and stage 3 aspects are detailed in ETS 300 184 (1992) and
ETS 300 185 (1992), respectively.

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ETS 300 183: October 1992
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ETS 300 183: October 1992
1 Scope
This standard defines the stage one of the Conference call, add-on (CONF) 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 CONF supplementary service enables a user to participate in, and control, a simultaneous
communication involving a number of users.
The CONF supplementary service is applicable to all circuit-switched telecommunications services
carrying speech.
This standard is applicable to the stage two and three standards for the ISDN CONF 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, or as a capability or possibility), this shall be reflected in the text of the
relevant stage two and three standards.
Furthermore, conformance to this standard is met by conforming to the stage three standard 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 the
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 Q.9 (1988): "Vocabulary of switching and signalling
terms".
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ETS 300 183: October 1992
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.
Service; telecommunications service: see CCITT Recommendation I.112 [2], § 2.2, definition 201.
Supplementary service: see CCITT Recommendation I.210 [3], § 2.4.
Served user: the user to whom the CONF supplementary service is provided.
Basic access: see CCITT Recommendation Q.9 [4], § 1, definition 1551.
Primary rate access: see CCITT Recommendation Q.9 [4], § 1, definition 1552.
Conference: a call having the capability of involving a number of users who can communicate
simultaneously.
Conference controller: the (served) user who invokes the CONF supplementary service and controls the
addition and removal of conferees.
Conferee: any user involved in the conference, other than the conference controller.
Party: any user participating in the conference.
Private communication: a communication between the conference controller and another user who may
be a past/potential conferee. This communication is entirely separate from the conference.
(Existing) active call: a call for which the connection has been established.
Idle state: in this state, the user invokes the CONF supplementary service without an associated call.
4 Symbols and abbreviations
ISDN Integrated Services Digital Network
CONF Conference call, add-on
PSTN Public Switched Telephone Network
5 Description
The CONF supplementary service shall apply to the basic access and to the primary rate access.
The CONF supplementary service enables a user to participate in and control a simultaneous
communication involving a number of users.
The CONF supplementary service can be invoked from the idle state. As a network option, the CONF
supplementary service can be invoked from an existing active call.
When the CONF supplementary service is invoked, conference resources are allocated to the served
user. In the case of invocation from an active call, this call will be connected to the conference resources.

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ETS 300 183: October 1992
6 Procedures
6.1 Provision and withdrawal
The CONF supplementary service shall be provided by prior arrangement with the service provider.
The maximum number of parties allowed in a conference shall be a network option.
The CONF supplementary service shall be withdrawn by the service provider upon request by 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
The CONF supplementary service can be invoked from the idle state. As a network option, the CONF
supplementary service can be invoked from an existing call.
NOTE: It is the responsibility of the user to ensure that the calls are compatible.
6.2.3.1 Beginning the conference from the idle state
The served user can request the CONF supplementary service. The number of parties required in the
conference can be indicated in the request.
If the number of parties is not indicated, a maximum value allowed by the network shall be used.
A successful request for the CONF supplementary service shall result in the network reserving conference
resources capable of serving the required number of parties.
6.2.3.2 Beginning the conference from an active call
As a network option, the following procedures can be used when a user already has a call on which the
connection has been established.
The served user can request the CONF supplementary service, indicating in the request that an existing
call shall be connected to the conference. The number of parties required in the conference can be
indicated in the request.
If the number of parties is not indicated, the maximum value allowed by the network shall be used.
A successful request for the CONF supplementary service shall result in the network assigning
conference resources capable of supporting the required number of parties. The other user in the call
indicated in the request for the CONF supplementary service shall be connected to the conference.
If the call indicated in the request was not held by the served user, then the served user shall be
connected to the conference. If the call indicated in the request was held by the served user, then the
conference shall be held by the served user.
The conferee shall be notified that their call has been added to the conference (see subclause 6.2.3.5).

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ETS 300 183: October 1992
6.2.3.3 Managing the conference
During the conference, the served user can:
- invoke the call hold supplementary service in order to put their own connection to the conference on
hold. Whilst the conference is on hold, the remaining parties in the conference can communicate
with each other. The served user can then make a call to a potential conferee;
- create a private communication with one of the parties. The network shall place the conference on
hold for the served user. The required party shall be removed from the conference and connected
to the served user. The private communication shall be considered as a normal call. Whilst the
conference is on hold, the remaining parties can still communicate with each other;
- terminate the entire conference, i.e. all connections to the conference shall be terminated and the
conference resources shall be released;
- explicitly disconnect one party from the conference, i.e. the connection between that party and the
conference shall be terminated;
- add a conferee, to which a private communication has been established, provided the maximum
number of parties is not exceeded. For an incoming call on which the connection has already been
established, the conference controller can request that this call be added into the conference using
the add-on procedures. As a network option, this request can be accepted or rejected;
After addition of a party, the connection between the served user and the conference shall remain in
the state it was prior to the request to add the potential conferee. If the conference was on hold, the
served user shall retrieve the conference in order to participate in the conference;
- isolate a conferee. The conferee indicated by the conference controller shall be prevented from
communicating with the conference without being removed from it;
- reattach a conferee previously isolated. The conferee can communicate again with the other parties
in the conference.
If only one conferee remains, or no conferees remain, as a result of any of the above operations, the
conference shall be considered to still be in progress.
6.2.3.4 Actions available to conferees
During the conference any of the conferees can:
- invoke the call hold supplementary service in order to put their own connection to the conference on
hold; or
- release their connection to the conference.
If only one conferee remains, or no conferees remain, as a result of any of the above operations, the
conference shall be considered to still be in progress.

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ETS 300 183: October 1992
6.2.3.5 Notification of participants
Each participant in the conference shall be informed by the service provider about the state of their call
when a change occurs. When a party is added to the conference, a party is explicitly disconnected from
the conference, a party is removed from the conference in order to create a private communication with
that party, a party is isolated from the conference, or a party is reattached to the conference, then all the
remaining conferees shall be informed.
Conferees shall not be informed when the conference controller holds or retrieves the whole conference.
NOTE: During an interim period of time, some networks may not support the transfer of
notifications.
6.2.4 Interrogation
Not applicable.
6.3 Exceptional procedures
6.3.1 Activation, deactivation and registration
Not applicable.
6.3.2 Erasure
Not applicable.
6.3.3 Invocation and operation
If a user tries to invoke the CONF supplementary service and the service provider cannot comply with that
request, the service provider shall deny the request and give the served user the reason for rejection.
Possible reasons for rejection are:
- the CONF supplementary service is not subscribed to;
- the requested number of conferees exceeds the maximum number allowed by the network (N);
- resources cannot be allocated.
If the service provider cannot satisfy the request to manipulate the conference (e.g. a request to add a
further conferee fails, for example, because the conference has been cleared, the maximum number of
conferees allowed has already been reached, or closed user group restrictions are not met) the served
user shall receive an indication that the request is rejected, with the re
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