ETSI ETS 300 675 ed.1 (1996-11)

Integrated Services Digital Network (ISDN); Audiographic conference teleservice; Service description

DE/TE-04031

Digitalno omrežje z integriranimi storitvami (ISDN) – Daljinske storitve: Avdiografična konferenca – Opis storitve

General Information

• Status: Published
• Publication Date: 05-Nov-1996
• Technical Committee: TE 4 - Audiovisual and Voice Terminals
• Current Stage: 12 - Completion
• Due Date: 15-Nov-1996
• Completion Date: 06-Nov-1996
• Ref Project: SIST ETS 300 675 E1:2003 - Integrated Services Digital Network (ISDN); Audiographic conference teleservice; Service description

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 675 E1:2003
01-december-2003
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Integrated Services Digital Network (ISDN); Audiographic conference teleservice;
Service description
Ta slovenski standard je istoveten z: ETS 300 675 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
33.160.60 9HþSUHGVWDYQLPXOWLPHGLMVNL Multimedia systems and
VLVWHPLLQRSUHPD]D teleconferencing equipment
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SIST ETS 300 675 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 675 E1:2003

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SIST ETS 300 675 E1:2003
EUROPEAN ETS 300 675
TELECOMMUNICATION November 1996
STANDARD
Source: ETSI TC-TE Reference: DE/TE-04031
ICS: 33.080
Key words: Audiographic, conference, inband, ISDN, stage 1
Integrated Services Digital Network (ISDN);
Audiographic conference teleservice;
Service description
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
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 1996. All rights reserved.

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ETS 300 675: November 1996
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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Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions.9
4 Abbreviations.10
5 Description .10
5.1 General description.10
5.2 Basic facilities .10
5.2.1 Audio facilities .10
5.2.2 Conference control facility .11
5.2.3 Data transmission facility.11
5.2.4 Graphics facility .11
5.3 Other facilities .11
6 Procedures.11
6.1 Provision and withdrawal .11
6.2 Normal procedures .12
6.2.1 Originating the call (call establishment).12
6.2.2 Indications during call establishment.13
6.2.3 Terminating the conference .13
6.2.3.1 Point-to-point conference .13
6.2.3.2 Multipoint conference.13
6.2.4 Change of communication mode .13
6.2.5 Multipoint control .14
6.2.6 Data communication .14
6.3 Exceptional procedures .14
6.3.1 Situations at the calling user side.14
6.3.2 Situations at the called user side.14
6.3.3 Situations due to network conditions.15
6.3.4 Retention of call information.15
7 Intercommunication and interworking considerations .15
7.1 Fall-back procedures .15
7.1.1 Fall-back to the telephony 3,1 kHz teleservice.15
7.1.1.1 Procedures .15
7.1.1.2 Interworking with non-ISDNs .16
7.1.2 Fall-back to the telephony 7 kHz teleservice.16
7.2 Interworking with private ISDNs.16
7.3 Restricted network operation .16
8 Interaction with other supplementary services .16
9 Static description of the service using attributes .17
9.1 Low layer attributes.17
9.2 Access attributes .17
9.3 High layer attributes .18
9.4 General attributes .18
Annex A (informative): Relation between standards and recommendations relevant for the
audiographic conference service.19

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Annex B (informative): Applicability of supplementary services to the audiographic conference
teleservice. 20
B.1 General. 20
B.2 Audiographic conference based on one circuit-mode 64 kbit/s connection . 20
B.3 Audiographic conference based on two or more circuit-mode 64 kbit/s connections. 21
Annex C (informative): Bibliography . 22
History. 23

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ETS 300 675: November 1996
Foreword
This European Telecommunication Standard (ETS) has been produced by the Terminal Equipment (TE)
Technical Committee of the European Telecommunications Standards Institute (ETSI).
Transposition dates
Date of adoption of this ETS: 25 October 1996
Date of latest announcement of this ETS (doa): 28 February 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 August 1997
Date of withdrawal of any conflicting National Standard (dow): 31 August 1997

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1 Scope
This European Telecommunication Standard (ETS) defines the stage one of the audiographic conference
teleservice 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 in annex C), but does not deal with the details of the human
interface itself.
This ETS defines the interworking requirements of private ISDNs with the public ISDN.
In addition, this ETS specifies the base functionality where the service is provided to the user via a private
ISDN.
This ETS 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.
Charging principles are outside the scope of this ETS.
The values of the general attributes are outside the scope of this ETS.
The audiographic conference teleservice is a real-time teleservice in which high quality speech, control
signals and data are interchanged using one or more circuit-mode 64 kbit/s connection(s).
This ETS is applicable to the stage two and stage three standards for the ISDN audiographic conference
teleservice. The terms "stage two" and "stage three" are also defined in CCITT Recommendation I.130.
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 will be reflected in the text of the relevant stage two
and stage three standards.
Furthermore, conformance to this ETS is met by conforming to the stage three standard with the field of
application appropriate to the equipment being implemented concerning characteristics at the
user-network interface, and by conforming to the ETS on the end-to-end characteristics appropriate to the
equipment being implemented. Therefore, no method of testing is provided for this ETS.
NOTE: In the current version of this ETS the use of protocols in the ITU-T T.120 series of
recommendations (see annex C) is an option. This position may be reviewed later.
2 Normative references
This ETS 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 ETS 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.112 (1985)88): "Vocabulary of terms for ISDNs".
[2] CCITT Recommendation I.221 (1985)88): "Common specific characteristics of
services".
[3] ETS 300 144 (1996): "Integrated Services Digital Network (ISDN); Audiovisual
services; Frame structure for a 64 kbit/s to 1 920 kbit/s channel and associated
syntax for inband signalling".
[4] ETS 300 111 (1992): "Integrated Services Digital Network (ISDN); Telephony
3,1 kHz teleservice, Service description".
[5] ETS 300 263 (1994): "Integrated Services Digital Network (ISDN); Telephony
7 kHz teleservice, Service description".

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[6] CCITT Recommendation G.728 (1992): "Coding of speech at 16 kbit/s using
low-delay code-excited linear prediction".
[7] ETS 300 143 (1994): "Integrated Services Digital Network (ISDN): Audiovisual
services; Inband signalling procedures for audiovisual terminals using digital
channels up to 2 048 kbit/s".
[8] ITU-T Recommendation T.122 (1985)93): "Multipoint communication service for
audiographics and audiovisual conferencing service definition".
[9] ITU-T Recommendation T.124 (1995): "Generic conference control".
[10] ITU-T Recommendation T.123 (1985)94): "Protocol stacks for audiographic and
audiovisual teleconference applications".
[11] CCITT Recommendation G.711 (1985)88): "Pulse code modulation (PCM) of
voice frequencies".
[12] CCITT Recommendation G.722 (1985)88): "7 kHz audio-coding within
64 kbit/s".
[13] ETS 300 483 (1996): "Terminal Equipment (TE); Integrated Services Digital
Network (ISDN); Multipoint communication for audiovisual services; Main
functionalities and basic requirements for Multipoint Control Units (MCUs)".
[14] ETS 300 345 (1995): "Integrated Services Digital Network (ISDN): Interworking
between public ISDNs and private ISDNs for the provision of telecommunication
services. General aspects".
[15] ITU-T Recommendation H.242 (1985)96): "System for establishing
communication between audiovisual terminals using digital channels up to
1 920 kbit/s".
[16] CCITT Recommendation I.140 (1985)88): "Attribute technique for the
characterization of telecommunication services supported by an ISDN and
network capabilities of an ISDN".
[17] ETS 300 011 (1992): "Integrated Services Digital Network (ISDN); Primary rate
user-network interface, Layer 1 specification and test principles".
[18] ETS 300 012 (1992): "Integrated Services Digital Network (ISDN); Basic
user-network interface, Layer 1 specification and test principles".
[19] ETS 300 403-1 (1995): "Integrated Services Digital Network (ISDN); Digital
Subscriber Signalling System No. one (DSS1) protocol; Signalling network layer
for circuit-mode basic call control; Part 1: Protocol specification
(ITU-T Recommendation Q.931 (1993), modified)".
[20] ETS 300 402-1 (1995): "Integrated Services Digital Network (ISDN); Digital
Subscriber Signalling System No. one (DSS1) protocol; Data link layer;
Part 1: General aspects (ITU-T Recommendation Q.920 (1993), modified)".
[21] ETS 300 267-1 (1994): "Integrated Services Digital Network (ISDN); Telephony
7 kHz and videotelephony teleservices Digital Subscriber Signalling System No.
one (DSS1) protocol; Part 1: Protocol specification".
[22] ITU-T Recommendation H.243 (1985)93): "Procedures for establishing
communication between three or more audiovisual terminals using digital
channels up to 1920 kbit/s".
[23] ITU-T Recommendation T.125 (1994): "Multipoint communication service
protocol specification".

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3 Definitions
For the purposes of this ETS, the following definitions apply:
Integrated Services Digital Network (ISDN): An integrated services network that provides digital
connections between user-network interfaces (CCITT Recommendation I.112 [1], subclause 2.3,
definition 308).
restricted network: A network consisting of multiples of 64 kbit/s links, but where only multiples of
56 kbit/s are usable for the terminals.
service; telecommunications service: That which is offered by a service provider to its customers in
order to satisfy a specific telecommunication requirement (CCITT Recommendation I.112 [1],
subclause 2.2, definition 201).
NOTE: Bearer service and teleservice are types of telecommunication service. Other types of
telecommunication service may be identified in the future.
supplementary service: A service which modifies or supplements a basic telecommunication service.
Consequently, it cannot be offered to a customer as a standalone service. It needs to be offered together
with or in association with a basic telecommunication service. The same supplementary service may be
common to a number of telecommunication services (based on CCITT Recommendation I.210,
subclause 2.4).
teleservice: A type of telecommunication service that provides the complete capability, including terminal
equipment functions, for communication between users according to protocols established by agreement
between service providers (CCITT Recommendation I.112 [1], subclause 2.2, definition 203).
audiographic conference terminal: A terminal that supports the audiographic conference teleservice.
7 khz terminal: A terminal that supports the telephony 7 kHz teleservice.
3,1 khz terminal: A terminal that supports only the telephony 3,1 kHz teleservice.
videotelephone terminal: A terminal that supports the videotelephony teleservice.
fall-back: The mechanism whereby the request for the audiographic conference service, which includes
an indication that an alternative teleservice is acceptable, results in a call using the alternative teleservice.
In the case of the audiographic conference teleservice, the alternative teleservices are the telephony
7 kHz or the telephony 3,1 kHz teleservices.
served user: A user to whom the audiographic conference teleservice is provided.
network determined user busy: As described in CCITT Recommendation I.221 [2], subclause 2.1.4.
user determined user busy: As described in CCITT Recommendation I.221 [2], subclause 2.1.4.
retention timer: This timer specifies the amount of time that the network retains all the call information
supplied by the calling user when the call encounters busy or is terminated. Implementation of this timer is
a network option. The value for this timer shall be greater than 15 seconds.
Multipoint Control Unit (MCU): A piece of equipment located in a node of the network or in a terminal
that connects several terminals and, according to certain criteria, processes audiovisual signals and
distributes them to the connected terminals.
sub-channel: Each bit position of the byte of a 64 kbit/s channel as defined in ETS 300 144 [3].
service channel: The eight sub-channels of a 64 kbit/s channel as defined in ETS 300 144 [3].
Multi Layer Protocols (MLP): As defined in the ITU-T T.120 series of recommendations.

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ISDN number: A number conforming to the numbering plan and structure specified in
CCITT Recommendation E 164.
4 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
ISDN Integrated Services Digital Network
MCS Multipoint Communication Service
MCU Multipoint Control Unit
MLP Multi Layer Protocols
PSTN Public Switched Telephone Network
5 Description
5.1 General description
The audiographic conference teleservice is a real-time teleservice in which speech is transmitted together
with signals for conference control and data communication between a terminal and a Multipoint Control
Unit (MCU) or between two terminals by means of one or more 64 kbit/s circuit-mode connections in the
ISDN.
The audiographic conference teleservice comprises two cases:
- case a): audiographic conference based on using one circuit-mode 64 kbit/s connection; and
- case b): audiographic conference based on using two or more circuit-mode 64 kbit/s connections.
An audiographic conference terminal shall be capable of supporting the telephony 3,1 kHz teleservice as
described in ETS 300 111 [4] and the telephony 7 kHz teleservice as described in ETS 300 263 [5]. To
improve the data communication capacity, the encoding specified in CCITT Recommendation G.728 [6]
may be implemented as an option.
The audiographic conference teleservice shall allow communication between:
- two users (e.g. terminals) in a point-to-point configuration via the ISDN over a B-channel;
- three or more users in a multipoint configuration.
User information and user-to-user signalling shall be transferred over the B-channel. User-network
signalling shall be provided over the D-channel.
A Multipoint Control Unit (MCU), to which all locations are connected individually over the ISDN, is
required for the interconnection of three or more users in a multipoint configuration. Two or more MCUs
may be interconnected to increase the number of participants of a multipoint conference.
The network provides tones and/or announcements to support this teleservice. Tones and/or
announcements can be used to indicate the progress (or lack of progress) of a call. The application and
meaning of the tones and announcements are a national matter and outside the scope of this ETS.
A description of the relation between the different elements described in this ETS can be found in
annex A.
5.2 Basic facilities
5.2.1 Audio facilities
The audio system shall be designed to offer handsfree communication to two or more participants at each
site. The participants should be allowed to listen and speak simultaneously. The speech transmission
bandwidth shall nominally be 7 kHz, although this may be reduced when the conference has been opened
to participants served by a non-ISDN network.

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5.2.2 Conference control facility
A conference control system for governing call establishment and call termination, controlling conference
modes and audio/image signals; and for transmission of conference control signals (e.g. floor requests,
tokens), shall be provided.
The conference control system shall, as a minimum, be based on the signals and procedures specified in
ETS 300 144 [3] and ETS 300 143 [7]. For improved performance the Multipoint Communication Service
(MCS) as described in ITU-T Recommendation T.122 [8] using the Generic Conference Control protocols
described in ITU-T Recommendation T.124 [9] can be used.
5.2.3 Data transmission facility
A data transmission facility shall be provided. The facility shall be based on data channels as defined in
ETS 300 144 [3]. For improved performance the protocol stack defined in ITU-T Recommendation
T.123 [10] should be implemented.
5.2.4 Graphics facility
The graphics system shall be designed to transmit documents, charts, diagrams, etc., during the
conference.
NOTE: As a minimum, a facsimile group 3 transmission in a separate B-channel should be
available.
5.3 Other facilities
As options, other facilities can be provided as applications using the MCS specified in
ITU-T Recommendation T.122 [8]. Examples are:
- still picture;
NOTE 1: ITU-T Recommendation T.126 specifies a Multipoint still image and annotation
protocol.
- file transfer.
NOTE 2: ITU-T Recommendation T.127 specifies a Multipoint binary file transfer protocol.
6 Procedures
6.1 Provision and withdrawal
The audiographic conference shall either be provided after prior arrangement with the service provider, or
shall be generally available.
NOTE: As a service provider option, the audiographic conference teleservice can be offered
with several subscription options which apply separately to each ISDN number, or
groups of ISDN numbers on the interface. For each subscription option, only one value
can be selected.
It should be noted that in this context an interface may consist of a group of physical
interfaces.
Subscription options for the interface are summarized in table 1.

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Table 1
Subscription option Value
Maximum number of information m: where m is not greater than the number
channels available of information channels on the interface.
Maximum number of total calls n: where n is not greater than the number of
present information channels on the interface.
The user can be identified by an ISDN number or a group of ISDN numbers, or globally for all ISDN
numbers on the interface.
More than one ISDN number can be associated with the interface as a part of a supplementary service
such as the multiple subscriber number supplementary service. In the case of one ISDN number, the
option given in table 1 for the number of calls can only exceed the number of information channels in
association with a supplementary service (e.g. the call waiting supplementary service). As a network
provider option, separate values may be specified for incoming and for outgoing calls for either or both of
the limits.
6.2 Normal procedures
For case a) of the audiographic conference teleservice, communication is by means of a single 64 kbit/s
connection, and as a result a single call shall be established. The procedures are given in
subclause 6.2.1.
For case b) of the audiographic conference teleservice, communication is by means of two or more
64 kbit/s connections, and as a result two or more calls shall be established. For the establishment of the
first call, the procedures of subclause 6.2.1 shall apply. The subsequent calls shall be established using
the procedures given in subclause 6.2.1, provided that the first call has already been established.
The network shall provide out of band indications to indicate call progress. Network generated tones
and/or announcements shall be provided for the audiographic conference teleservice.
6.2.1 Originating the call (call establishment)
The audiographic conference teleservice is originated by the originating user activating the terminal,
performing the service selection, if applicable for the originating terminal, and terminating selection. During
this process, the originating user shall be given the appropriate indications as to the state of the call.
The end-to-end path is framed according to ETS 300 144 [3]. The inband protocol shall be established
according to ETS 300 143 [7].
Call 1 shall be established before initiating Call 2.
NOTE 1: Call 1 is devoted to transfer of speech and data. The transmission audio mode on the
end-to-end digital path is defined according to ETS 300 144 [3], using the procedures
defined in ETS 300 143 [7].
Audio tones provided to the user during Call 1 shall be as for the telephony 3,1 kHz teleservice, given in
ETS 300 111 [4].
The subsequent calls can only be originated by the calling user's terminal after the connection has been
established on Call 1 and after the end-to-end mode initialization procedure is completed.
NOTE 2: The subsequent calls are devoted to data communication.

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6.2.2 Indications during call establishment
At the called side the calls shall be accepted after successful checking of compatibility information by the
terminal(s) addressed.
After initiating Call 1 the calling user shall receive an acknowledgement that the network is able to process
the call. The called user shall receive an indication of the arrival of an incoming audiographic conference
call. The calling user shall also be given an indication that the call is being offered to the called user, when
an indication is received by the network that the called user is being informed of this call.
The acceptance of Call 1 by the called user (answer), shall cause the indications to be removed and the
bi-directional communication path to be provided.
After initiating each subsequent call, the calling user shall receive an acknowledgement that the network is
able to process the call. The called user shall receive an indication of the arrival of an incoming
audiographic conference call.
The acceptance of the subsequent calls by the called user (answer), shall cause the bi-directional
communication path to be provided.
6.2.3 Terminating the conference
6.2.3.1 Point-to-point conference
A request to terminate the audiographic conference teleservice can be generated by either of the users. If
one user terminates the service, the other user(s) shall be given an appropriate indication.
6.2.3.2 Multipoint conference
A request to terminate the call(s) can be generated by either the user or the MCU controlled by the MCU
director or the user given the Chair control described in ITU-T Recommendation H.243 [22]. If one user
terminates his call to the MCU, the other user(s) shall be given an appropriate indication.
The termination of the whole conference shall be controlled by the MCU or by the user given the Chair-
control.
NOTE: An MCU could be designed to establish the call to a given user if this connection is
unintentionally released.
6.2.4 Change of communication mode
As a result of end-to-end integrity on the audiographic conference teleservice, 3,1 kHz telephony calls and
7 kHz telephony calls, it shall be possible to change between different communication modes according to
ETS 300 143 [7].
Depending on the terminal capabilities, it may be possible to change between the following
communication modes:
- 3,1 kHz speech (CCITT R
...