SIST ETS 300 143 E1:2003

SLOVENSKI STANDARD
SIST ETS 300 143 E1:2003
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Avdiovizualne storitve –
Postopki znotrajpasovnega krmiljenja pri avdiovizualnih terminalih, ki uporabljajo
digitalne kanale s hitrostmi do 2 048 kbit/s
Integrated Services Digital Network (ISDN); Audiovisual services Inband signalling
procedures for audiovisual terminals using digital channels up to 2 048 kbit/s
Ta slovenski standard je istoveten z: ETS 300 143 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST ETS 300 143 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 143 E1:2003

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SIST ETS 300 143 E1:2003
EUROPEAN ETS 300 143
TELECOMMUNICATION May 1994
STANDARD
Source: ETSI TC-TE Reference: DE/TE-04116
ICS: 33.020, 33.040.40
ISDN, audiovisual services
Key words:
Integrated Services Digital Network (ISDN);
Audiovisual services
Inband signalling procedures for audiovisual terminals
using digital channels up to 2 048 kbit/s
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 - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1994. All rights reserved.
New presentation - see History box

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ETS 300 143: May 1994
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions.7
4 Symbols and abbreviations .8
5 Basic principles and rules.8
5.1 Capabilities .9
5.1.1 Audio capabilities.9
5.1.2 Video capabilities.9
5.1.3 Transfer rate capabilities.10
5.1.4 Data capabilities .10
5.1.5 Restricted networks: capability.10
5.1.6 Encryption and extension-BAS capabilities.10
5.1.7 Neutral capability.10
5.1.8 Hierarchy in capabilities.11
5.1.9 Rules for capability sets .11
5.2 Commands .12
5.2.1 Audio commands .12
5.2.2 Video commands .12
5.2.3 LSD/MLP commands .12
5.2.4 Rules for commands .13
5.3 Sequencing of BAS codes .13
5.4 Values of unoccupied bits.14
6 Basic sequences .14
6.1 Capability exchange (sequence A) .14
6.1.1 Initiating terminal .14
6.1.2 Terminal not initiating .15
6.1.3 Identification of the end of sequence A .15
6.1.4 Change of capability set .15
6.2 Mode switching (sequence B).16
6.2.1 Symmetry/asymmetry (point-to-point) .16
6.2.2 Symmetry/asymmetry (multipoint).16
6.3 Frame reinstatement (sequence C).16
6.3.1 Outgoing framing.16
6.3.2 Incoming framing.17
7 Procedures.17
7.1 Mode initialisation procedure (inband).17
7.1.1 Initial channel.17
7.1.2 Additional channels .18
7.2 Mode switching .18
7.2.1 Dynamic mode switching from a framed mode to another mode.18
7.2.2 Dynamic mode switching from an unframed mode to another mode.19
7.3 Mode forcing procedures .19
7.3.1 Mode forcing.19
7.3.2 Mode-0 forcing .19
7.4 Procedure for use of Encryption Control Signal (ECS) channel .19
7.5 Procedure for activation and de-activation of data channels .20
7.5.1 Activation of data channels .20
7.5.2 De-activation of data channels.20
7.5.3 Simultaneous transmission of Low Speed Data (LSD) and MLP.20

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7.6 Procedure for use of BAS-extension codes . 20
8 Fault recovery . 21
8.1 General recovery procedures. 21
8.2 Incoming A=1 . 22
8.2.1 Incoming A=1 on I-channel. 22
8.2.2 Incoming A=1 on additional channels. 22
8.3 Mode mismatch. 22
8.4 Loss of alignment . 23
8.4.1 Unexpected loss of frame alignment in the initial channel. 23
8.4.2 Loss of multiframe alignment in initial channel. 23
8.4.3 Loss of frame alignment in an additional channel . 23
8.4.4 Loss of multiframe alignment in additional channel. 23
8.5 Loss of connection or channel . 23
8.5.1 Loss of the only channel . 24
8.5.2 Loss of the only additional channel. 24
8.5.3 Loss of an additional channel if more than one additional channel was
established. 24
8.5.4 Loss of channels including the initial channel if more than one channel
was established . 24
8.6 Terminal Equipment Alarm (TEA) (optional) . 24
Annex A (informative): Bibliography . 25
History. 26

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Foreword
This European Telecommunication Standard (ETS) has been produced by the Terminal Equipment (TE)
Technical Committee of the European Telecommunications Standards Institute (ETSI).
The attention of the user of this ETS is drawn to the possibility that compliance may require the use of
technology covered by patent or similar rights.
ETSI is not responsible for identifying patent or similar rights or for granting licences which may be
required and, as a result, ETSI is not in a position to give authoritative or comprehensive information
concerning the existence, validity or scope of patent or similiar rights in connection with this ETS.

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1 Scope
This ETS specifies inband signalling procedures for establishing communication between audiovisual
terminals using digital channels of up to 2 048 kbit/s. The system is based on the frame structure and
associated syntax as specified in ETS 300 144 [1]. The procedures are required to establish a compatible
mode upon call set-up, to switch between modes during a call and to allow for use of supplementary
services as described in ETS 300 145 [2].
A separate ETS (DE/TE-04120) is under preparation which specifies the method of testing required to
identify conformance to this ETS.
This ETS is applicable to terminals supporting the telephony 7 kHz or videotelephony teleservice and to
other terminals designed for audiovisual communication.
NOTE: It is assumed within this ETS that, due to frame synchronisation and signalling
overheads, the bit rate which can be used for user data in 2 048 kbit/s transmission
systems is limited to 1 920 kbit/s.
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 300 144: "Integrated Services Digital Network (ISDN): Audiovisual services,
Frame structure for a 64 to 1 920 kbit/s channel and associated syntax for
inband signalling".
[2] ETS 300 145: "Integrated Services Digital Network (ISDN): Audiovisual services,
Videotelephone systems and terminal equipment operating on one or two 64
kbit/s channels".
[3] CCITT Recommendation G.711 (1988): "Pulse code modulation (PCM) of voice
frequencies".
[4] CCITT Recommendation G.722 (1988): "7 kHz audio-coding within 64 kbit/s".
[5] CCITT Recommendation G.725 (1988): "System aspects for the use of the 7
kHz audio codec within 64 kbit/s".
[6] CCITT Recommendation G.728 (1992): "Coding of speech at 16 kbit/s using
low-delay code-excited linear prediction".
3 Definitions
For the purposes of this ETS, the definitions given in Clause 3 of ETS 300 144 [1] and the following
definition apply:
Capability: Ability to receive, demultiplex and decode the corresponding signal.

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4 Symbols and abbreviations
For the purposes of this ETS, the following symbols and abbreviations apply:
BAS Bit-rate Allocation Signal
C&I Control and Indication
CIF Common Intermediate Format
ECS Encryption Control Signal
ETS European Telecommunication Standard
ETSI European Telecommunications Standards Institute
FAS Frame Alignment Signal
FAW Frame Alignment Word
1)
H-MLP High speed Multi Layer Protocol
H0 384 kbit/s channel
H11 1 536 kbit/s channel
H12 1 920 kbit/s channel
HSD High Speed Data
ISDN Integrated Services Digital Network
ITU-TS International Communications Union Telecommunications Standardization
LSB Least Significant Bit
LSD Low Speed Data
MBE Multi-Byte Extension
MCC Multipoint Command Conference
MCS Multipoint Command Symmetrical Data-transmission
MCU Multipoint Control Unit
2)
MLP Multi Layer Protocol
MPI Minimum Picture Interval
MSB Most Significant Bit
QCIF Quarter Common Intermediate Format
SBE Single Byte Extension
SC Service Channel
TEA Terminal Equipment Alarm
TS Time Slot
TS1 Time Slot 1
VCF Video Command "Freeze-picture request"
VCU Video Command "Fast-update request"
(xxx) [yy] Symbolism, coded representation of a BAS following table 8 of ETS 300 144 [1].
(xxx) corresponds to the binary attribute of the BAS, and [yy] corresponds to the
value of the BAS in decimal
5 Basic principles and rules
The sequences and procedures in this ETS ensure that only those signals are transmitted which can be
received and appropriately treated by the remote terminal, without ambiguity. This requires that the
capabilities of each terminal to receive and decode be known to the other terminal, and that suitable
commands be transmitted to set the demultiplexer and decoders accordingly.
The total capability of a terminal to receive and decode various signals is made known to the other
terminal by transmission of its capability set (see subclause 5.1.9).
The frame structure described in ETS 300 144 [1] is used for mode initialisation and dynamic mode
switching (see the following subclauses) and, more generally, to transmit capabilities and commands. ETS
300 144 [1] defines a Bit-rate Allocation Signal (BAS) which is used, inter alia, to indicate the coding
algorithm(s) and to define the multiplex of the various bit streams (audio, video, data, Encryption Control
Signal (ECS), frame structure) within the frame.
BAS codes are classified by attribute and value; the first three bits represent the BAS attribute: each
attribute may therefore have up to 32 defined values.

1)
MLP protocols are under discussion in ITU-TS.
2)
MLP protocols are under discussion in ITU-TS.

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Four BAS attributes are commands: they define the multiplex within the next and following sub-
multiframes, as well as an audio coding algorithm, and therefore command the distant receiver to treat the
signals accordingly. The four attributes are independent; that is, a value of one attribute does not modify
that of another.
Further BAS attributes are defined to signal terminal capabilities to the distant terminal. When received,
these attributes do not directly affect the current transmission mode. However, they may lead to the
initiation of a specific action to be carried out by the terminal. This feature is used in the mode initialisation
procedure and in the mode forcing procedure (see Clause 7).
The third bit of the Frame Alignment Signal (FAS) (see ETS 300 144 [1]) in odd frames of the initial
channel, called the A-bit, is set to 0 on acquiring frame alignment and, if desired or necessary, multiframe
alignment; the A-bit is set to 1 on loss of frame or multiframe alignment. Consequently, a terminal which is
receiving a framed signal with the A-bit set to 0 can assume that the distant terminal is able to receive
BAS capability sets and act upon changes of BAS.
A terminal having capabilities for single-channel working only, and without encryption capability, does not
need to seek and gain multiframe alignment since the latter serves for numbering and synchronising
multiple channels.
5.1 Capabilities
Capability values are defined in ETS 300 144 [1].
5.1.1 Audio capabilities
All audiovisual terminals claiming conformance to this ETS shall be capable of transmitting and receiving
audio with both A-law and μ-law companding, according to ITU-T Recommendation G.711 [3]. They shall
transmit at least one audio capability.
Both ITU-T Recommendation G.711 [3] capabilities shall be sent, unless it is desired to force the remote
terminal to transmit a particular one of the two. Receipt of just one value (A or μ) from the remote terminal
shall be interpreted as an indication that it cannot decode signals to the other law. Receipt of no ITU-T
Recommendation G.711 [3] capabilities shall be interpreted as an indication that it can decode signals to
both laws.
Table 1: Meaning of the A-law and μμ-law capability inside a capability set
A-law capability meaning (referring to the
μμ-law capability
received transmitting terminal)
received
No No can decode A-law and μ-law
Yes No
cannot decode μ-law
No Yes cannot decode A-law
Yes Yes
can decode A-law and μ-law
5.1.2 Video capabilities
For the picture format, a terminal may have either Quarter Common Interchange Format (QCIF) capability
alone, or both QCIF and Common Intercharge Format (CIF) capabilities.
The QCIF capability shall be followed by one Minimum Picture Interval (MPI) value. The CIF capability
shall be followed by two MPI values, the first applicable to QCIF and the other to CIF.

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For the MPI, the following are valid values:
- 1/29,97;
- 2/29,97;
- 3/29,97;
- 4/29,97 seconds.
5.1.3 Transfer rate capabilities
The capability to receive a given number of 64 kbit/s channels includes the capability to receive fewer 64
kbit/s channels. Similarly, the capability to receive a given number of 384 kbit/s channels (H0 channels)
includes the capability to receive fewer H0 channels. In both cases the receiving terminal shall be able to
synchronise the connected additional channels to the initial channel and maintain that synchronism
throughout the period of connection.
All other ranges of capability shall be signalled by inclusion in the capability set of more than one transfer
rate capability code. For example, a terminal may list its transfer-rate capabilities as [2B and H0 and H11
and H12]; in this case 1B capability is also implied.
All terminals are capable of receiving a single B-channel or 64 kbit/s time-slot of a larger channel;
therefore the 1B capability need not normally be transmitted; the exception is when no other transfer-rate
capability is included in the set, when higher rates have been in force previously in the same call.
5.1.4 Data capabilities
If a terminal is able to accept more than one data rate of whatever type (Low Speed Data (LSD), High
Speed Data (HSD), Multi Layer Protocol (MLP), High-speed Multi Layer Protocol (H-MLP)), then all
relevant values shall be included in the capability set. Statement of one value does not include any other
values (that is, there is no hierarchy in data rate capabilities).
5.1.5 Restricted networks: capability
A terminal connected to a network whose B-channels are effectively restricted to p x 56 kbit/s (p = 1 to 6),
or whose channels at H0, or higher, are restricted by ones-density considerations, shall declare the
capability value (100) [22] (restrict capability) as given in ETS 300 144 [1]. All terminals intended for
interworking with terminals on restricted networks shall have the capability to respond to this code by
using the multiplex and the BAS commands defined for the restricted network as given in ETS 300 144 [1]
(see also subclause 8.3, item c).
5.1.6 Encryption and extension-BAS capabilities
These capabilities indicate, respectively, the ability of the terminal to open the Encryption Control Signal
(ECS) channel, and to accept Multi-Byte Extension (MBE) messages in the BAS position.
Once an ECS capability code has been transmitted it cannot be cancelled by omission from a subsequent
capability exchange.
5.1.7 Neutral capability
Neutral capability (100) [0] shall never be transmitted.
It may be received from other terminals conforming to ITU-T Recommendation H.242. If it is not enclosed
between BAS capability markers, the sequence is invalid.
If neutral capability is included in a capability set together with other capabilities, the sequence is invalid.

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5.1.8 Hierarchy in capabilities
The following capability codes are hierarchically structured:
- G.711 (A or μ or both) < G.722-48;
- G.711 (A or μ or both) < G.728;
- 1B < 2B < 3B < 4B < 5B < 6B;
- 1H0 < 2H0 < 3H0 < 4H0 < 5H0;
- QCIF < CIF;
- 4/29,97 < 3/29,97 < 2/29,97 < 1/29,97.
The meaning of these expressions is that, in every case, a terminal having the capability to the right of a
"<" sign shall also have all the capabilities to the left thereof.
5.1.9 Rules for capability sets
A capability set is valid if it conforms to the rules set out in this Clause. If a received capability set is found
to have broken one or more of these rules it shall be considered invalid and consequently ignored. The
capability set consists of the capability marker (111) [24] followed by all currently valid values, in any order
(except for MPI values). No values should be repeated within a set (except for MPI values, see subclause
5.1.2).
All codes included in the capability set shall correspond, by the definitions given in ETS 300 144 [1], to
properties which can be activated in the terminal at the appropriate moment following the receipt of a
relevant command.
Allowed capability set values are capability marker (111) [24], capabilities (100) [1-31] and (101) [0-31]
and escape table capability values. No commands are permitted in a capability set. Neutral capability shall
not be included in a capability set.
The capability set shall conform to table 2, which summarises the capabilities that can be simultaneously
valid.
Table 2: BAS capabilities that can be simultaneously valid
Audio One or more values from
{A-law, μ-law, G.722-48, Au-16 kbit/s(G.728), Au-ISO}
Video Absent, or
{ [(QCIF plus one MPI value) or (CIF plus two MPI values)] and/or
 video-ISO and/or
 AV-ISO}
3)
Transfer rate Absent (meaning rate = 64 kbit/s only ), or
{ no or one value of {1B; 2B; 3B; 4B; 5B; 6B}, and/or
 no or one value of {1H0; 2H0; 3H0; 4H0; 5H0}, and/or
 H11, and/or
 H12, and/or
 any relevant values from {128, 192, 256, 512, 768, 1 152,
 1 472 kbit/s}}
Restricted network Absent or present
Low-Speed Data (LSD) Absent or all relevant values
High-Speed Data (HSD) Absent or all relevant values
Low-speed MLP Absent or all relevant values
High-speed MLP Absent or all relevant values
Applications in data channel Absent or all relevant values
Capabilities defined in ITU-T Absent or all relevant values
Recommendation H.230
Encryption Absent or all relevant values
Multiple-Byte Extension Absent or all relevant values

3)
When reducing the transfer-rate capability to 64 kbit/s from an higher rate, the value (001)[0] shall be included.

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A capability set shall always be followed by either:
- one or more repetitions of the set; or
- capability marker and at least one of the commands (000) [0 to 31] or (001) [0 to 31] or (010) [0 to
31] or (011) [0 to 31], according to the received capability set.
The number of repetitions of the capability set is not limited.
A capability set shall never be empty. A minimum of one valid capability value other than capability marker
shall be present in a capability set. There shall never be two capability markers in consecutive BAS
positions.
If it is desired to change the capability set during its transmission, the existing set shall first be completed
without change, followed by a capability marker and at least one command; thereafter, a changed set may
be sent.
A capability set shall not include any HSD/H-MLP capabilities whose bit rates exceed the transfer rate
capability (e.g. 256 kbit/s HSD rate for 2B transfer rate).
A neutral capability set is defined as: [capability marker + neutral capability]. If a terminal receives a
neutral capability set while already transmitting in a framed mode and receiving A=0, it shall ignore it.
5.2 Commands
5.2.1 Audio commands
Audio cannot penetrate into fixed rate data (LSD or MLP) bit positions. It can expand its capacity into
vacant, or video or variable data bit positions. It can reduce its capacity within the audio bit positions
currently occupied.
5.2.2 Video commands
The video transmission is governed by the video-on and video-off commands. When switched on, the
video signal occupies all the capacity, both in the initial channel and in any additional channels, which is
not specifically allocated to other signals by other commands (ECS, Audio, LSD/MLP regardless of being
fixed rate or variable rate). Thus, different video bit rates shall result from audio, transfer-rate, ECS and
data commands, the resultant video bit rate being:
4) 5)
transfer rate, less audio rate, less data rate , less encryption control channel , less FAS and
6)
BAS .
Video can be turned on at any time even if the available capacity for video is zero at the corresponding
sub-multiframe; (it may happen, for example, that video is switched on just before the variable rate LSD or
MLP channel is closed); the decoder shall not ignore "video on" even in this case, otherwise a mode
mismatch occurs.
5.2.3 LSD/MLP commands
Fixed rate LSD/MLP cannot penetrate into Audio bit positions nor into fixed rate MLP/LSD bit positions. It
can expand its capacity into vacant, or video, or variable-MLP, or variable-LSD bit positions. It can reduce
its capacity within the data bit positions currently occupied.
Both fixed and variable-rate LSD/MLP may be changed without first closing the data channel.
NOTE: There can only be one LSD and one MLP channel at any instant.

4)
If present.
5)
If present.
6)
In all the channels/time-slots where they are present.

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Variable rate LSD/MLP occupies all bit positions which are not assigned by other fixed rate commands
(ECS, Audio, fixed rate MLP/LSD). If video has been on, it is excluded from the same channel when
variable-LSD or variable-MLP is turned on. If variable-LSD/MLP has been on, opening a variable rate
MLP/LSD channel should be preceded by closing the existing variable-LSD/MLP channel. Variable rate
LSD or MLP can be turned on even if the available capacity for it is zero at the corresponding sub-
multiframe; (it may happen, for example, that the variable MLP is switched on just before closing the LSD
channel which has been occupying all the capacity other than audio) the decoder shall not ignore "variable
rate LSD or MLP on" eve
...