SIST I-ETS 300 654 E1:2003

• Abstract:

  To specify D-channel signalling procedures, related terminal audio, video and in-band signalling actions of a videotelephone reference terminal supporting one or two B-channels in the ISDN

• 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 I-ETS 300 654 ed.1 (1996-09) - Integrated Services Digital Network (ISDN); Videotelephony terminals; Interim D-channel signalling aspects

SIST I-ETS 300 654 E1:2003 is the Slovenian standard identical to ETSI I-ETS 300 654 Edition 1. It specifies interim D-channel signalling for ISDN videotelephony terminals, including how a terminal sets up, retries, and accepts calls when network support is incomplete. The standard is aimed at basic access videotelephone terminal equipment connected at the S-reference point or coincident S/T-reference point, and it covers one or two B-channel operation.

What does SIST I-ETS 300 654 E1:2003 specify?

SIST I-ETS 300 654 E1:2003 specifies the D-channel signalling procedures for videotelephony terminal equipment in ISDN during a transition period where not all networks implement the preferred videotelephony procedures. It also covers the related terminal audio, video, and in-band signalling actions that let calls complete more reliably across different network capabilities.

The document is organized into scope, normative references, definitions and abbreviations, and the main clause on short term D-channel signalling procedures. Annex A is normative and explains how Bearer Capability and High Layer Compatibility are used in outgoing and incoming SETUP messages. Annex B is an informative bibliography.

Annex	What it covers
Annex A	Normative rules for Bearer Capability and High Layer Compatibility in outgoing and incoming SETUP messages
Annex B	Informative bibliography

What are the key requirements of SIST I-ETS 300 654 E1:2003?

Network handling during the transition period

Clause 4.1 defines three network types for interim operation. Type 1 supports the ETS 300 267-1 procedures fully, type 2 supports them at access but not in ISUP, and type 3 supports neither. The terminal shall be programmable for the relevant network type, and the user shall be able to change that preset, because the signalling coding depends on the network reached.

Outgoing initial calls

For the initial connection, the terminal shall choose the SETUP information elements according to the network type and whether fallback is allowed, as described in clause 4.2.1 and Annex A. If a videotelephony attempt is rejected because the requested bearer capability is not supported, the terminal shall retry automatically with a different bearer coding, and in some cases later retry again as telephony 3,1 kHz teleservice. In practice, this means the terminal must be ready for an automatic second attempt and must inform the user when repeated attempts occur.

Additional connection for videotelephony

Clause 4.2.2 covers the second connection. The same addressing information is generally used as for the first call, although the user may request different addressing information. The terminal shall insert High Layer Compatibility indicating videotelephony and, when the second path is accepted, shall verify the relationship between the two calls using CLI and, if needed, in-band signalling.

Incoming calls and call identification

Clause 4.3.1 says an incoming SETUP with Bearer Capability indicating unrestricted digital information is treated as a videotelephony request, even if octet 5 is missing. If High Layer Compatibility is present, it shall indicate videotelephony and possibly initial channel. If the terminal supports the service, it shall alert; otherwise it shall ignore the call. This matters because some incoming calls are ambiguous between videotelephony and telephony 7 kHz until in-band signalling completes.

Restricted networks and user feedback

Clause 4.2.1.4 and 4.3.4 cover interworking with restricted networks. The terminal shall use the restricted-network coding defined in ETR 018 and be ready to accept a changed bearer capability or to clear the call if it cannot interwork. When the bearer service removes tones and announcements from the B-channel, the terminal shall give progress information by display or locally generated tones.

What terms does SIST I-ETS 300 654 E1:2003 define?

• I-channel - the initial or only B-channel in a call where in-band signalling follows the document’s principles.
• videotelephony teleservice - a real-time audiovisual service carried over one or two 64 kbit/s circuit-mode connections in ISDN.
• telephony 7 kHz teleservice - a real-time voice service using 7 kHz audio over one circuit-mode 64 kbit/s connection.
• telephony 3,1 kHz teleservice - a speech service with 3.1 kHz audio bandwidth and D-channel signalling.
• CLI - Calling Line Identification, used to help match the initial and second connection.
• CLIR - Calling Line Identification Restriction, which can make that matching harder.
• UDI-TA - Unrestricted Digital Information with Tones and Announcements, used in the preferred videotelephony call setup path.

Who uses SIST I-ETS 300 654 E1:2003?

Manufacturers and integrators of ISDN videotelephone terminal equipment use this standard to implement call setup, fallback, and in-band signalling correctly. Network operators and service providers use it to understand how terminals should behave when network signalling support is partial or delayed.

Test labs and quality teams use it to check that a terminal handles SETUP, ALERTING, CONNECT, CONNECT ACKNOWLEDGE, and DISCONNECT messages in the expected way. It is also relevant to buyers or specifiers who need terminals that can interwork with different ISDN network types and restricted-network cases.

Which standards are used with SIST I-ETS 300 654 E1:2003?

• ETS 300 267-1 - provides the main DSS1 protocol for telephony 7 kHz and videotelephony teleservices.
• ETS 300 403-1 - provides the DSS1 protocol for circuit-mode basic call control and the call state behavior used by this document.
• ETR 018 - defines how Bearer Capability, High Layer Compatibility, and Low Layer Compatibility are coded, including restricted-network use.
• ETS 300 143 - defines in-band signalling procedures for audiovisual terminals.
• ETS 300 145 - defines videotelephone systems and terminal equipment operating on one or two 64 kbit/s channels.
• I-ETS 300 245-5 - defines in-band signalling procedures for telephony 7 kHz terminals.

What does the SIST I-ETS 300 654 E1:2003 document contain?

The document contains the short term D-channel signalling procedures for outgoing and incoming videotelephony calls, including network-type handling, fallback behavior, and the treatment of restricted networks. Annex A gives the detailed use of Bearer Capability and High Layer Compatibility in outgoing and incoming SETUP messages, with separate guidance for call setup, alerting, and CONNECT handling.

It also includes the rules for when a terminal should move to the Active state and when it should start in-band signalling. The bibliography in Annex B points to the related ISDN, DSS1, videotelephony, and telephony standards used alongside this one.

SLOVENSKI STANDARD
01-december-2003
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9LGLNLVLJQDOL]DFLMHSR]DþDVQHP'NDQDOX
Integrated Services Digital Network (ISDN); Videotelephony terminals; Interim D-channel
signalling aspects
Ta slovenski standard je istoveten z: I-ETS 300 654 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.

INTERIM
EUROPEAN I-ETS 300 654
TELECOMMUNICATION September 1996
STANDARD
Source: ETSI TC-TE Reference: DI/TE-04111
ICS: 33.080
Key words: ISDN, videotelephony
Integrated Services Digital Network (ISDN);
Videotelephony terminals;
Interim D-channel signalling aspects
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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I-ETS 300 654: September 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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I-ETS 300 654: September 1996
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .8
4 Short term D-channel signalling procedures .8
4.1 General .8
4.2 Outgoing call.9
4.2.1 Videotelephony teleservice, outgoing call for the initial connection.9
4.2.1.1 Outgoing call for network type 1 .9
4.2.1.2 Outgoing call for network type 2 .10
4.2.1.3 Outgoing call for network type 3 .10
4.2.1.4 Outgoing call for interworking with restricted networks .11
4.2.1.5 Procedures for all types of networks .11
4.2.2 Videotelephony teleservice, outgoing call for the second connection .12
4.3 Incoming call.12
4.3.1 Videotelephony teleservice, call request for the initial connection .12
4.3.2 Videotelephony teleservice, call request for the second connection.13
4.3.3 Call request for the telephony 7 kHz teleservice .13
4.3.4 Incoming call from restricted networks.14
Annex A (normative): Use of the Bearer Capability and High Layer Compatibility information
elements in the outgoing and incoming SETUP message .15
A.1 Call setup by the originating terminal .15
A.2 Alerting of the called terminal.16
A.3 CONNECT message.16
Annex B (informative): Bibliography.17
History.18

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I-ETS 300 654: September 1996
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I-ETS 300 654: September 1996
Foreword
This Interim European Telecommunication Standard (I-ETS) has been produced by the Terminal
Equipment (TE) Technical Committee of the European Telecommunications Standards Institute (ETSI).
Proposed announcement date
Date of adoption of this I-ETS: 23 August 1996
Date of latest announcement of this I-ETS (doa): 31 December 1996
An ETSI standard may be given I-ETS status either because it is regarded as a provisional solution ahead
of a more advanced standard, or because it is immature and requires a "trial period". The life of an I-ETS
is limited to three years after which it can be converted into an ETS, have it's life extended for a further
two years, be replaced by a new version, or be withdrawn.

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I-ETS 300 654: September 1996
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I-ETS 300 654: September 1996
1 Scope
This Interim European Telecommunication Standard (I-ETS) is applicable to Integrated Services Digital
Network (ISDN) basic access video telephony terminal equipment for connection at the S-reference point
or coincident S/T-reference point. It describes the D-channel signalling procedures which may be
implemented by terminals connected to the pan-European ISDN for use in cases where either:
a) the originating network has not implemented the procedures according to ETS 300 267-1 [1]; or
b) when interworking with a terminal connected to a digital network which does not support fully
compatible procedures.
The implementation of the procedures specified in ETS 300 267-1 [1] are likely to be introduced at
different points in time by the various network providers at the access (D-channel signalling, DSS1) or in
the network (Signalling system No. 7, ISDN User Part (ISUP)). Some networks (e.g. some non-European
networks) may not even implement those procedures at all. The support of this I-ETS by the terminal will
ensure an improved probability of success of videotelephony calls and avoid the occurrence of
unexpected clearing of calls as long as networks have not fully implemented the procedures according to
ETS 300 267-1 [1].
The requirements in this I-ETS are based on the procedures specified in ETS 300 267-1 [1] and
ETS 300 403-1 [2] and the use of the Bearer Capability, Low Layer Compatibility and High Layer
Compatibility information elements as specified in ETR 018 [3].
NOTE: The characteristics of the ISDN user-network interface are specified in ETS 300 012,
ETS 300 125 (see annex B), and ETS 300 403-1 [2].
2 Normative references
This I-ETS incorporates by dated and 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 I-ETS only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
[1] ETS 300 267-1 (1994): "Integrated Services Digital Network (ISDN); Telephony
7 kHz and videotelephony teleservices; Digital Subscriber Signalling System No.
one (DSS1); Part 1: Protocol specification".
[2] 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]".
[3] ETR 018 (Edition 3): "Integrated Services Digital Network (ISDN); Application of
the Bearer Capability (BC); High Layer Compatibility (HLC) and Low Layer
Compatibility (LLC) information elements by terminals supporting ISDN
Services".
[4] ETS 300 143: "Integrated Services Digital Network (ISDN); Audiovisual services;
Inband signalling procedures for audiovisual terminals using digital channels up
to 2 048 kbit/s".
[5] ETS 300 145: "Integrated Services Digital Network (ISDN); Audiovisual services;
videotelephone systems and terminal equipment operating on one or two 64
kbit/s channels".
[6] I-ETS 300 245-5 (1995): "Integrated Services Digital Network (ISDN); Technical
characteristics for telephony terminals; Part 5: Wideband (7 kHz) handset
telephony".
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I-ETS 300 654: September 1996
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this I-ETS, the relevant definitions used in ETS 300 143 [4], ETS 300 144 (see annex
B) and CCITT Recommendations I.112, I.230 and I.240 (see annex B) apply.
I-channel: The initial (or only) B-channel allocated to a call where inband signalling according to the
principles described in ETS 300 144 is applied.
modes of operation: For the videotelephony teleservice in the ISDN, the modes of operation are defined
in table 1 of ETS 300 145 [5].
telephony 3,1 kHz teleservice: A teleservice providing speech transmission at an audio bandwidth of
3,1 kHz. The communication is bi-directional, with both directions active during the speech phase. User
information is provided over a B-channel, signalling is provided over the D-channel (based on
ETS 300 111, clause 5 (see annex B)).
telephony 7 kHz teleservice: A real-time 7 kHz teleservice in which speech (7 kHz or 3,1 kHz bandwith)
can be interchanged using one circuit-mode 64 kbit/s connection. The audio bandwith conforms to CCITT
Recommendations G.722 and G.711 (see annex B) (based on ETS 300 263, clause 5 (see annex B)).
terminal types: For the videotelephony teleservice in the ISDN, the terminal types are defined in table 2
of ETS 300 145 [5].
videotelephony teleservice: A real-time audiovisual teleservice in which speech and moving pictures are
interchanged by means of one or two 64 kbit/s circuit-mode connections in the ISDN (based on
ETS 300 264, clause 5 (see annex B)).
3.2 Abbreviations
For the purposes of this I-ETS, the following abbreviations, in addition to those used in
CCITT Recommendations I.112, I.230 and I.240 (see annex B), apply.
CLI Calling Line Identification
CLIR Calling Line Identification Restriction
ISDN Integrated Services Digital Network
ISUP ISDN User Part
MSN Multiple Subscriber Number supplementary service
TE Terminal Equipment
UDI Unrestricted Digital Information
UDI-TA Unrestricted Digital Information with Tones and Announcements
4 Short term D-channel signalling procedures
4.1 General
The procedures of ETS 300 267-1 [1], i.e. provision of the Bearer Capability with information transfer
capability "Unrestricted Digital Information with Tones and Announcements (UDI-TA)" and the fallback
procedure (use of two Bearer Capability and High Layer Compatibility information elements in the SETUP
message), may not be implemented in all European and non-European ISDNs for an interim period of
time or at all. As a short term solution, terminals supporting the videotelephony teleservice shall meet,
along with the procedures specified in ETS 300 267-1 [1], the requirements described in the following
subclauses.
In principle, 3 different types of networks can be distinguished for the transition period:
Network type 1: This type of network supports the procedures specified in ETS 300 267-1 [1], in
particular the use of two Bearer Capability/High Layer Compatibility information
elements, at the access for the D-channel signalling as well as in the network for
the signalling system no. 7 (ISUP).

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I-ETS 300 654: September 1996
Network type 2: This type of network supports the procedures specified in ETS 300 267-1 [1] at
the access for the D-channel signalling, but not in the network for the signalling
system no. 7 (ISUP). In this case, the fallback procedures (use of two Bearer
Capability/High Layer Compatibility information elements in the SETUP
message), are not supported by the network.
Network type 3: This type of network does not support the procedures described in
ETS 300 267-1 [1], neither at the access for the D-channel signalling, nor in the
network for the signalling system no. 7 (ISUP).
NOTE 1: The networks type 2 and 3 may support of the Bearer Capability "UDI-TA" independent
from the fallback procedures.
NOTE 2: Videotelephony terminals may be connected outside Europe to another type of
network, providing only restricted transmission capabilities (e.g. 56 kbit/s).
For videotelephony terminals complying with this I-ETS, it shall be possible to pre-set the terminal to the
type of network which it is intended to be connected to. Procedures for changing the preset-value for the
network type shall be available for the user.
NOTE 3: The term "network type" is used only in the context of this I-ETS.
NOTE 4: Conformance test requirements for ETS 300 403-1 [2] are given in ETS 300 403 part 4
and part 5 .
NOTE 5: Conformance test requirements for the procedures in ETS 300 267-1 [1] are not yet
published.
Conformance test requirements are not included in this I-ETS.
4.2 Outgoing call
4.2.1 Videotelephony teleservice, outgoing call for the initial connection
Dependent on the type of network the terminal is connected to, the information elements contained in the
SETUP message for the initial connection shall be chosen according to tables A.1 and A.2 of annex A.1.
4.2.1.1 Outgoing call for network type 1
For network type 1, the procedures of ETS 300 267-1 [1] shall apply.
When the call setup for the initial connection is rejected by the network with a cause value that indicates
that the requested Bearer Capability (UDI-TA) is not supported by the destination network or the called
terminal, e.g. 31, 47, 65, 88, 127, then the terminal shall automatically repeat the call setup procedures by
requesting the "circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service category". The coding
of the Bearer Capability information element is described in ETR 018 [3].
NOTE 1: For further possible cause values, see ETS 300 485 (see annex B).
A High Layer Compatibility information element as described in ETR 018 [3], indicating "videotelephony,
CCITT Recommendation F.721" and possibly "initial channel", may be inserted into the SETUP message.
NOTE 2: For an interim period of time it is not guaranteed that all networks will support the
transport and/or delivery of the High Layer Compatibility information element to the
called terminal. In addition, transport of octet 4 may, in some circumstances be
supported, but the transport of octet 4a will not.

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I-ETS 300 654: September 1996
4.2.1.2 Outgoing call for network type 2
For network type 2, the procedures of ETS 300 267-1 [1] apply with the following exception:
The terminal shall always send a SETUP message containing only one Bearer Capability information
element and one High Layer Compatibility information element according to table A.2 to the network, even
in the case where fallback is allowed.
When the call setup for the initial connection is rejected by the network with a cause value that indicates
that the requested Bearer Capability (UDI-TA) is not supported by the destination network or the called
terminal, e.g. 31, 47, 65, 88, 127, then the terminal shall automatically repeat the call setup procedures by
requesting the "circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service category". The coding
of the Bearer Capability information element is described in ETR 018 [3].
NOTE 1: For further possible cause values, see ETS 300 403-1 [2].
A High Layer Compatibility information element as described in ETR 018 [3], indicating "videotelephony,
CCITT Recommendation F.721" and possibly "initial channel", may be inserted into the SETUP message.
NOTE 2: For an interim period of time it is not guaranteed that all networks will support the
transport and/or delivery of the High Layer Compatibility information element to the
called terminal. In addition, transport of octet 4 may, in some circumstances be
supported, but the transport of octet 4a will not.
If this second call attempt is rejected with a cause value 18 (no user responding) and the calling user had
allowed fallback, then a third call setup shall automatically be initiated as a request for the telephony
3,1 kHz teleservice.
The human user shall be informed about the repeated call attempts.
NOTE 3: For networks of type 2, the procedures of ETS 300 267-1 [1] could apply in principle.
However, it should be noted that, when a user requests the videotelephony teleservice
with fallback allowed, fallback will always occur. Thus the resulting service will be the
telephony 3,1 kHz teleservice.
4.2.1.3 Outgoing call for network type 3
For network type 3, when initiating an outgoing call for the initial connection, the terminal shall request the
"circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service category". The coding of the Bearer
Capability information element is described in ETR 018 [3].
A High Layer Compatibility information element as described in ETR 018 [3], indicating "videotelephony,
CCITT Recommendation F.721" and possibly "initial channel", may be inserted into the SETUP message.
NOTE: For an interim period of time it is not guaranteed that all networks will support the
transport and/or delivery of the High Layer Compatibility information element to the
called terminal. In addition, transport of octet 4 may, in some circumstances, be
supported but the transport of octet 4a will not.
If the call attempt is rejected with a cause value 18 and the user had allowed fallback, then another call
setup shall automatically be initiated as a request for the telephony 3,1 kHz teleservice.
The user shall be informed about the repeated call attempt.
...