ETSI ETS 300 145 ed.2 (1996-01)

Integrated Services Digital Network (ISDN); Audiovisual services; Videotelephone systems and terminal equipment operating on one or two 64 kbit/s channels

RE/TE-04038

Digitalno omrežje z integriranimi storitvami (ISDN) – Avdiovizualne storitve – Videotelefonski sistemi in terminalska oprema, ki delujejo z enim ali dvema kanaloma s hitrostjo 64 kbit/s

General Information

• Status: Published
• Publication Date: 18-Jan-1996
• Technical Committee: TE 4 - Audiovisual and Voice Terminals
• Current Stage: 12 - Completion
• Due Date: 12-Jan-1996
• Completion Date: 19-Jan-1996
• Ref Project: SIST ETS 300 145 E2:2003 - Integrated Services Digital Network (ISDN); Audiovisual services; Videotelephone systems and terminal equipment operating on one or two 64 kbit/s channels

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 145 E2:2003
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Avdiovizualne storitve –
Videotelefonski sistemi in terminalska oprema, ki delujejo z enim ali dvema
kanaloma s hitrostjo 64 kbit/s
Integrated Services Digital Network (ISDN); Audiovisual services; Videotelephone
systems and terminal equipment operating on one or two 64 kbit/s channels
Ta slovenski standard je istoveten z: ETS 300 145 Edition 2
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST ETS 300 145 E2:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 145 E2:2003

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SIST ETS 300 145 E2:2003
EUROPEAN ETS 300 145
TELECOMMUNICATION January 1996
STANDARD Second Edition
Source: ETSI TC-TE Reference: RE/TE-04038
ICS: 33.080
Key words: ISDN, audiovisual services
Integrated Services Digital Network (ISDN);
Audiovisual services;
Videotelephone systems and terminal equipment operating
on one or two 64 kbit/s channels
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 300 145: January 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 .9
5 System description .10
5.1 Block diagram and identification of elements (informative).10
5.2 Videotelephone terminal types .11
5.3 Signal structure and procedures .12
5.3.1 Frame structure .12
5.3.2 Control and Indication (C&I) .12
5.3.3 In-band signalling procedures.14
5.3.4 Communication modes of videotelephones.15
6 Terminal procedures and arrangements related to videotelephony call.15
6.1 Basic call establishment and mode initialisation .15
6.1.1 Phase A - Call set-up for the initial channel.16
6.1.2 Phase B - mode initialisation .16
6.1.2.1 Case of 1B call.17
6.1.2.2 Case of 2B call.17
6.1.3 Phase CA - call set-up for the additional channel.18
6.1.4 Phase CB - mode initialisation on the additional channel.18
6.2 Videotelephony communication - Phase C .18
6.2.1 Mode switching .18
6.2.2 Capability change .19
6.2.3 Loopbacks for maintenance purposes (optional).19
6.2.4 Terminal arrangements .19
6.2.4.1 Video transmission.19
6.2.4.2 Picture definition.20
6.2.4.3 Exchange of video by mutual agreement (optional).20
6.2.4.4 Audio decoding .20
6.2.4.5 Delay compensation (optional).20
6.3 Change of connection arrangements.20
6.3.1 Expanding a 1B call to a 2B call .20
6.3.2 Reducing a 2B call to a 1B call .21
6.4 Call clearing - Phase D/E .21
6.4.1 Clearing terminal.21
6.4.2 Cleared terminal .21
7 Implementation of supplementary services by videotelephony terminals.22
7.1 Calling Line Identification Presentation (CLIP) and Connected Line Identification Presentation
(COLP) .22
7.2 Multiple Subscriber Number (MSN) .22
7.3 Call Completion to Busy Subscriber (CCBS) and Call Completion on No Reply (CCNR) .22
7.4 Call Deflection (CD).22
7.5 Supplementary services resulting in connection interruption .22
7.5.1 Procedure P.23
7.5.2 Terminal Portability (TP).23
7.5.2.1 Invocation procedure.23
7.5.2.2 Resumption after invocation of Terminal Portability.23
7.5.3 Hold .23
7.5.3.1 Invocation procedure.23

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7.5.3.2 Retrieval after invocation of HOLD .24
7.5.4 Explicit Call Transfer (ECT) .24
7.5.4.1 Procedures for the transferring terminal A.24
7.5.4.2 Procedures for the transferred and transferred-to terminal .25
8 Optional enhancements.25
8.1 Data ports.25
8.2 Encryption .25
9 Fault indication.25
Annex A (informative): Detailed steps and procedures .26
Annex B (informative): Bibliography .33
History.34

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ETS 300 145: January 1996
Foreword
This European Telecommunication Standard (ETS) was produced by the Terminal Equipment (TE) Technical
Committee of the European Telecommunications Standards Institute (ETSI).
Transposition dates
Date of adoption of this ETS: 31 January 1996
Date of latest announcement of this ETS (doa): 30 April 1996
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 October 1996
Date of withdrawal of any conflicting National Standard (dow): 31 October 1996

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1 Scope
This 2nd edition of ETS 300 145 specifies the system requirements for a Videotelephone using one or two
B-channels, when connected to the S point or coincident S and T reference point of the pan-European Integrated
Services Digital Network (ISDN). These requirements ensure end-to-end compatibility of terminals supporting the
videotelephony teleservice described in ETS 300 264 [1].
This ETS is applicable in whole to Terminal Equipment (TE) supporting the videotelephony teleservice;
subclauses 5.3, 6.1, 6.2 and clause 8 are also applicable to Multipoint Control Units (MCUs) using one or two
B-channels.
The specific requirements which apply to a terminal in order to support various options related to videoconference
and/or data transmission are specified in other documents (e.g. Draft prETS 300 483 [2]).
Conformance to this ETS allows interworking with terminals supporting the telephony 3,1 kHz teleservice described
in ETS 300 111 [3], the telephony 7 kHz teleservice described in ETS 300 263 [4] and Public Switched Telephone
Network (PSTN) telephony terminals. Interworking with other audio-visual terminals can take place if their operation
on one or two B-channels is according to this ETS.
NOTE 1: Terminals in accordance with ITU-T Recommendation H.320 can interwork, if one or two
64 kbit/s (unrestricted or restricted) digital channels can be established between the terminals
(e.g. using a remote Channel Aggregation Unit in case of a 128 kbit/s H.320 single channel
terminal).
NOTE 2: Interworking with terminals according to CCITT Recommendation G.725 [5] is optional; it may be
restricted to mode 0.
NOTE 3: Audio and video signal interfaces are outside the scope of this ETS.
NOTE 4: Interfaces and protocols used for optional data transmission are outside the scope of this ETS.
The in-band signalling procedures are described in ETS 300 143 [6], and the syntax for these procedures is defined
in ETS 300 144 [7]. The video coding algorithm is described in ITU-T Recommendation H.261 [8].
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
apply.
[1] ETS 300 264: "Integrated Services Digital Network (ISDN); Videotelephony teleservice,
Service description".
[2] Draft prETS 300 483: "Terminal Equipment (TE); Integrated Services Digital Network
(ISDN); Multipoint Communications for Audiovisual Services; Main functionalities and
basic requirements for Multipoint Control Units and audiovisual terminals".
[3] ETS 300 111 (1992): "Integrated Services Digital Network (ISDN); Telephony 3,1 kHz
teleservice, Service description".
[4] ETS 300 263: "Integrated Services Digital Network (ISDN); Telephony 7 kHz teleservice,
Service description".
[5] CCITT Recommendation G.725 (1988): "System aspects for the use of the 7 kHz audio
codec within 64 kbit/s".
[6] ETS 300 143: "Integrated Services Digital Network (ISDN); Audiovisual services; In-band
signalling procedures for audiovisual terminals using digital channels up to 2 048 kbit/s".

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[7] ETS 300 144: "Integrated Services Digital Network (ISDN); Audiovisual services; Frame
structure for a 64 kbit/s to 1 920 kbit/s channel and associated syntax for in-band
signalling".
[8] ITU-T Recommendation H.261: "Video codec for audiovisual services at p x 64 kbit/s".
[9] ETS 300 102-1: "Integrated Services Digital Network (ISDN); User-network interface,
layer 3, Specifications for basic call control".
[10] ETS 300 012 (1991): "Integrated Services Digital Network (ISDN); Basic user-network
interface, Layer 1 specification and test principles".
[11] ETS 300 125 (1991): "Integrated Services Digital Network (ISDN); User-network interface
data link layer specification, Application of CCITT Recommendations Q. 920/I. 440 and
Q.921/I. 441".
[12] ITU-T/T.120 series of Recommendations:
- ITU-T Recommendation T.122: "Multipoint communication service for
audiographics and audiovisual conferencing, service definition";
- ITU-T Recommendation T.123: "Protocol stacks for audiographic and audiovisual
teleconference applications";
- ITU-T Recommendation T.125: "Multipoint communication service protocol
specification".
[13] CCITT Recommendation G.711 (1988): "Pulse code modulation (PCM) of voice
frequencies".
[14] CCITT Recommendation G.722 (1988): "7 kHz audio-coding within 64 kbit/s".
[15] CCITT Recommendation G.728 (1992): "Coding of speech at 16 kbit/s using low-delay
code-excited linear prediction".
[16] I-ETS 300 302, Parts 1 to 4: "Integrated Services Digital Network (ISDN); Videotelephony
teleservice".
[17] ETS 300 267-1: "Integrated Services Digital Network (ISDN); Telephony 7 kHz and
videotelephony teleservices, Digital Subscriber Signalling System No. one (DSS1), Part 1:
Protocol specification".
[18] I-ETS 300 245-5: "Integrated Services Digital Network (ISDN); Technical characteristics of
telephony terminals, Part 5: Wideband (7kHz) handset telephony".
[19] I-ETS 300 245-2: "Integrated Services Digital Network (ISDN); Technical characteristics of
telephony terminals, Part 2 - PCM A-law handset telephony".
[20] ITU-T Recommendation H.233: "Confidentiality system for audiovisual services".

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3 Definitions
For the purposes of this ETS, the definitions given in clause 3 of both ETS 300 143 [6] and ETS 300 144 [7] apply
along with the following:
additional channel: One of the channels between two users, which is not the I-channel (see ETS 300 144 [7]).
audio mute: Muting the loudspeaker of a terminal.
channel: A unidirectional link between two users.
connection: A bi-directional link between two users: it carries both (unidirectional) channels.
Control and Indication (C&I): End-to-end signalling between terminals, consisting of Control, which causes a state
change in the receiver, and Indication which provides for information as to the state or functioning of the system
(see also ETS 300 144 [7] for additional information and abbreviations).
data: Refer to any of these: Low Speed Data (LSD), High Speed Data (HSD), Multi Layer Protocol (MLP), High
Speed Multi Layer Protocol (H-MLP) as defined in ETS 300 144 [7].
I-channel: The initial or only B-channel as defined in ETS 300 144 [7].
In-band signalling: Signalling via the Bit-rate Allocation Signal (BAS) of the frame structure, as defined in
ETS 300 144 [7].
lip synchronisation: Operation to provide the feeling that the speaking motion of the displayed person is
synchronised with his speech.
man-machine interface: Interface between human user and terminal/system, consisting of a physical section
(electro-acoustic, electro-optic transducer, keys, etc.) and a logical section dealing with functional operation states.
4 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
BAS Bit-rate Allocation Signal
C&I Control and Indication
CLIP Calling Line Identification Presentation
COLP Connected Line Identification Presentation
CONNECT D-channel message (as in ETS 300 102-1 [9])
ECS Encryption Control Signal
ECT Explicit Call Transfer
FAS Frame Alignment Signal
H-MLP High Speed Multi Layer Protocol
HOLD Supplementary service
HSD High Speed Data
ISDN Integrated Services Digital Network
LSD Low Speed Data
MCU Multipoint Control Unit
MLP Logical data sub channel named "MLP"
NOTE: MLP previously referred to the ITU-T Recommendation T.120 [12] Multilayer Protocol, but now
this is just a name for the logical subchannel which may contain T.120 or H.224 protocol, or
Dummy data (see ETS 300 143 [6] and ETS 300 144 [7]).
MSB Most Significant Bit
MSN Multiple Subscriber Number
PSTN Public Switched Telephone Network
SC Service Channel
TEA Terminal Equipment Alarm
TERM A, TERM B Terminals
TERM C Terminal

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TP Terminal Portability
5 System description
A videotelephony terminal conforming to this ETS shall be connected to an ISDN basic access in accordance with
ETS 300 012 [10], ETS 300 102-1 [9] and ETS 300 125 [11]; then it cannot use more than 2 B-channels.
5.1 Block diagram and identification of elements (informative)
A generic videotelephony system is shown in figure 1. It consists of several (at least two) videotelephony terminals,
the ISDN, and possibly a Multipoint Control Unit (MCU).
A configuration of a complete videotelephony terminal consisting of several functional units is also shown in figure 1.
- Video I/O equipment includes camera(s), monitor(s), and video processing units to provide functions such as
split-screen scheme.
- Audio I/O equipment includes the handset and/or microphone(s), loud-speaker(s) and/or earphone(s), and
audio processing units to provide such functions as acoustic echo cancellation.
- Data I/O adaptor may be used for additional services, such as facsimile, or additional facilities (e.g. far end
camera control): it is optional.
- Telematic equipment includes visual aids such as an electronic blackboard and a still picture transceiver to
enhance the basic videotelephone communication as defined in ITU-T T.120 series of Recommendations
[12]: these are optional.
- The system control unit carries out such functions as:
- network access through user-to-network signalling,
- end-to-end in-band signalling to establish a suitable mode of operation,
- audio and video signal processing and multiplexing,
- data transmission and/or application.
- The video codec carries out redundancy reduction coding and decoding for video signals: the algorithm is as
defined in ITU-T Recommendation H.261 [8].
- The audio codec carries out redundancy reduction coding and decoding for audio signals: the algorithms are
defined in CCITT Recommendations G.711 [13], G.722 [14] and G.728 [15]. The audio characteristics are
defined in I-ETS 300 302, Parts 1 to 4 [16].
NOTE 1: Part 4 of this prI-ETS is still under study.
NOTE 2: Delay may be introduced into the audio path equal to the video codec delay, to maintain lip
synchronisation (see subclause 6.2.4.5).
- The Mux/dmux unit multiplexes transmitted video, audio, data and control signals into a single bit stream and
demultiplexes a received bit stream into constituent multimedia signals, as defined in ETS 300 144 [7].
- The network interface makes the necessary adaptation between the network and the terminal according to
the user-network interface requirements, as defined in ETS 300 012 [10], ETS 300 102-1 [9] and
ETS 300 125 [11].

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Video I/O
Video Codec
Equipment
Terminal 2
MUX
Audio I/O
Audio Codec Delay
Equipment +
I
N
N
DEMUX
E
T
Data I/O adaptor and/or
T
E ISDN MCU
Telematic equipment
W
R
S F
O
Y
A
End-to-end signalling
S
R
C
T
E K
E
M
Terminal 3
C D-channel signalling
O
N
T
R
O Terminal 1
L
Figure 1: Visual telephone system
- End-to-end signalling is defined in ETS 300 143 [6] and ETS 300 144 [7].
- User-to-network signalling is defined in ETS 300 102-1 [9], ETS 300 125 [11] and ETS 300 267-1 [17],
clause 7.
5.2 Videotelephone terminal types
Table 1 lists terminal types of videotelephone. The terminal type is categorised according to the audio
communication modes and the number of B-channels with which the terminal can communicate (see
subclause 5.3.4).
The terminal shall be able to operate at 1B and 2B transfer rate according to at least one of the operable audio
modes. The type of remote terminal is identified through the capability exchange defined in ETS 300 143 [6].

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Table 1: Videotelephone terminal type
Transfer rate 1 B 2 B
Xa Xb1 Xb2/3 Xb4 Xb5
TYPE
G.728 G.728 G.728 G.722
Transfer Audio
G.711 G.711 G.722 G.711
MODE
rate coding
G.711 G.711
a0 1B G.711
a1 1B G.728
b1 2B G.711
b2 2B G.722
b3 2B G.728
NOTE: "indicates operable mode".
5.3 Signal structure and procedures
5.3.1 Frame structure
The terminal shall conform to ETS 300 144 [7].
5.3.2 Control and Indication (C&I)
C&I shall be chosen from the general audiovisual set contained in ETS 300 144 [7]. For videotelephone systems,
relevant values are listed in table 2 giving their source, sink, synchronisation with picture, transmission channel and
reference for code word definition.
C&I functions are defined such that, under various circumstances, the audiovisual system operates in a fault-free
manner and also such that sympathetic presentation to users is possible. Some functions shall therefore be
mandatory, others optional.
Table 2 with its notes clarifies the circumstances under which C&I functions are "mandatory":
M denotes mandatory for any equipment;
CM denotes conditionally mandatory if the relevant option is declared for the audiovisual system;
R means not mandatory but recommended.
NOTE: All videotelephone terminals have a video source providing a picture of participants, and some
terminals may have optional additional video sources: the participant-picture source is
designated #1, having the associated symbol VIA. When incoming video is ON (BAS command
(010)[1] or (010)[2]) and VIA, VIA2, VIA3 have not been transmitted, source #1 is assumed.

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Table 2: C&I signals for videotelephone
Sync.
C&I with
C/I Source Sink Transmission Code word NOTES
(function or name) picture
(see below)
channel definition
RX TX
(1) (1)
Picture format I decoder coder no BAS ETS 300 144 M
[7]
Picture format C coder decoder yes embedded in H.261 [8] M M
video
Minimum decodable I decoder coder no BAS ETS 300 144 M
picture interval [7]
VCF C coder or decoder no BAS ETS 300 144 M
Video
MCU [7]
VCU C decoder coder no BAS ETS 300 144 MCM
or MCU [7] (3)
Freeze picture C coder decoder yes embedded in H.261 [8] M
release control video
MCU C terminal terminal no MLP ITU-T Rec. R R
related messages or MCU or MCU T.120 series (9) (9)
[12]
MCC / cancel-MCC C MCU terminal no BAS ETS 300 144 M
[7]
MCU
MCS / cancel MCS C MCU terminal no BAS ETS 300 144 CM
(or MCN) [7] (4)
MIZ and MIS C MCU terminal no BAS ETS 300 144 M
[7]
LCA C terminal terminal no BAS ETS 300 144
(1) [7]
Mainte-
LCV C terminal terminal no BAS ETS 300 144
(1) [7]
nance
LCD C terminal terminal no BAS ETS 300 144 MCM
(1) [7] (2)
LCO C terminal terminal no BAS ETS 300 144 MCM
(1) [7] (2)
Confe-
split-screen I sending receiving yes embedded in H.261 [8] CM
rence
indication terminal terminal video (5)
(continued)

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Table 2 (concluded): C&I signals for videotelephone
Sync.
C&I with
C/I Source Sink Transmission Code word NOTES
(function or name) picture
(see below)
channel definition
Document camera I sending receiving yes embedded in H.261 [8] CM
indication terminal terminal video (6)
Termi- AIA / AIM I sending receiving no BAS ETS 300 144 CM CM
nal terminal terminal [7] (7) (7)
VIA, VIA2, VIA3 I sending receiving no BAS ETS 300 144 CM CM
terminal terminal [7] (7) (7)
VIS
VIR I sending receiving no BAS ETS 300 144 CM CM
terminal terminal [7] (8) (8)
Data transmission C sending receiving no BAS + ETS 300 144
control terminal terminal MLP [7] R R
ITU-T / T.120 (10) (10)
series of Rec
[12].
Data
Video compatibility I sending receiving no BAS ETS 300 144 R R
terminal terminal [7]
(Dummy) (11) (11)
NOTE 1: RX - mandatory (or conditionally mandatory) to recognise and act upon.
TX - mandatory (or conditionally mandatory) to send when / if relevant conditions occur.
NOTE 2: Maintenance terminals only.
NOTE 3: Mandatory if the terminal cannot decode high or low video rates - see subclause 6.2.4.1.
NOTE 4: Mandatory for a terminal which can transmit LSD, MLP, HSD or H-MLP. Terminals not
obeying MCS shall not be able to exchange video in a multipoint call when other terminals
are using their data capability.
NOTE 5: Mandatory for a terminal which can transmit a split-screen picture to CCITT
Recommendation H.100.
NOTE 6: Mandatory for a terminal which has a document camera.
NOTE 7: Mandatory for a terminal which has user controls to mute audio or cut the video without
also switching off the audio/video channel within the transmitted frame.
NOTE 8: Mandatory if the terminal itself does not turn video on until it receives this code from the
remote terminal. See subclause 6.2.4.2.
NOTE 9: Recommended to support enhanced functionalities such as Chair-control, etc.
NOTE 10: Recommended for data transmission and/or additional applications.
NOTE 11: Recommended for a simple terminal in order to be able to participate to a multipoint
conference when other terminals are using a data sub channel (e.g. LSD or MLP).
5.3.3 In-band signalling procedures
The terminal shall conform to ETS 300 143 [6] for point-to-point communications.

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5.3.4 Communication modes of videotelephones
Communication modes of a videotelephone for the ISDN basic access are defined according to their channel
configuration and coding. All videotelephones shall be capable of operation in mode a and one or more of the
0
modes a1, b1, b2, b3.
The following modes of operation are defined for an ISDN basic interface (see also table 3):
Mode a : Mode 0U: 64 kbit/s audio to CCITT Recommendation G.711 [13], A or μ-law.
0
Mode 0F: 56 kbit/s audio to CCITT Recommendation G.711 [13], A or μ-law: 6,4 kbit/s
video to ITU-T Recommendation H.261 [8] may, or may not, be activated.
Mode a : 16 kbit/s audio to CCITT Recommendation G.728 [15] and 46,4 kbit/s video to
1
ITU-T Recommendation H.261 [8].
Mode a : Video only mode (62,4 kbit/s).
v
Mode b : 56 kbit/s audio to CCITT Recommendation G.711 [13] A or μ- law and 68,8 kbit/s video to
1
ITU-T Recommendation H.261 [8].
Mode b : 48 or 56 kbit/s audio to CCITT Recommendation G.722 [14] and 76,8 kbit/s or 68,8 kbit/s
2
video to ITU-T Recommendation H.261 [8].
Mode b : 16 kbit/s audio to CCITT Recommendation G.728 [15] and 108,8 kbit/s video to
3
ITU-T Recommendation H.26
...