SIST ETS 300 143/A1 E1:2003

• Abstract:

  To include requirements on A-law/u-law implementation in ETS 300 143

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI ETS 300 143/A1 ed.1 (1996-01) - Integrated Services Digital Network (ISDN); Audiovisual services; Inband signalling procedures for audiovisual terminals using digital channels up to 2 048 kbit/s

SIST ETS 300 143/A1 E1:2003 is the Slovenian adoption of ETS 300 143 Amendment 1 for Integrated Services Digital Network (ISDN) audiovisual services. It specifies inband signalling procedures for audiovisual terminals using digital channels up to 2 048 kbit/s, and this amendment adds requirements for A-law/μ-law handling and related terminal behaviour.

What does SIST ETS 300 143/A1 E1:2003 specify?

SIST ETS 300 143/A1 E1:2003 updates the signalling and capability procedures used by ISDN audiovisual terminals during a call. It focuses on how terminals announce audio, video and data capabilities, how they open and close data channels, and how they exchange control information inband.

The amendment is organized as changes to the original ETS 300 143 clauses on scope, references, symbols and abbreviations, audio capabilities, capability sets, commands, capability exchange, initial channel rules, data channel procedures, and optional network-address transmission.

Clause area	What the amendment addresses
1, 2, 4	Scope note, added references, updated abbreviations
5	Audio capabilities, valid capability sets, command rules
6, 7.1, 7.5, 7.7	Capability exchange, initial channel behaviour, data channels, network addresses

What are the key requirements of SIST ETS 300 143/A1 E1:2003?

Audio coding and capability handling

SIST ETS 300 143/A1 E1:2003 adds explicit A-law and μ-law handling for the start of a call. The default coding law at call start is A-law, and μ-law is used when the terminal knows the destination is in a μ-law region and the call has reached the ALERTING or CONNECT stage, or inband signalling has started.

The calling terminal is responsible for choosing the correct coding law. If no coding-law information is available, it keeps the default law and monitors the incoming signal to determine whether the far end is using A-law or μ-law PCM.

Capability sets and commands

SIST ETS 300 143/A1 E1:2003 tightens the rules for capability sets and commands. A received capability set that breaks the rules is invalid and ignored, and the set has a defined marker followed by currently valid values without repetition, except for MPI values and {Null}.

The amendment also replaces the capability table and the command summary. In practice, this means terminals must only signal the allowed audio, video, transfer-rate, data and control values, and they must obey the default values and expiry rules for commands.

Data channels and multiplexing

SIST ETS 300 143/A1 E1:2003 defines how MLP, H-MLP, LSD and HSD may be opened, combined and closed. MLP and H-MLP may be opened together, but LSD and HSD cannot be mixed with MLP or H-MLP unless the remote equipment has declared {H.224-sim}; LSD and HSD also cannot be open at the same time.

When a terminal opens a data channel, it must already have signalled that it can receive that data type and rate. The command must be sent before the channel bits are occupied by fixed-rate audio or other fixed data, so the terminal has to clear or reassign those bits first.

Capability exchange and initial channel rules

SIST ETS 300 143/A1 E1:2003 requires both terminals to exchange current capability sets in Sequence A. Either terminal may start, simultaneous start is allowed, and the terminal must keep the current multimedia multiplexing mode while this happens.

At the start of communication, BAS commands other than the default values must not be sent until Sequence A has finished. The amendment also limits repeated capability sets to 10 seconds and prevents endless repetition.

Optional network-address signalling

SIST ETS 300 143/A1 E1:2003 adds an optional procedure for requesting and returning network-address information. A terminal can ask for the initial channel address with NCA-i or for additional-channel addresses with NCA-a, and the remote endpoint can answer with the appropriate SBE or MBE forms.

What terms does SIST ETS 300 143/A1 E1:2003 define?

• A-law - The default audio encoding law at the start of a call.
• μ-law - The alternative audio encoding law used when the far end is known to be in a μ-law region.
• MLP - The logical data subchannel named "MLP"; the amendment treats it as a channel name rather than a protocol label.
• H-MLP - The high speed MLP logical subchannel.
• LSD - The low-speed data channel used in BAS signalling.
• HSD - The high-speed data channel used in BAS signalling.
• MCU - A Multipoint Control Unit used in multipoint audiovisual communication.
• Sequence A - The capability-exchange sequence where both terminals send their current capability sets.

Who uses SIST ETS 300 143/A1 E1:2003?

SIST ETS 300 143/A1 E1:2003 is used by designers and integrators of ISDN audiovisual terminals, multipoint conferencing equipment and Multipoint Control Units (MCUs). It is also relevant for test engineers, interoperability labs, quality managers and buyers who need to check that a terminal handles capability exchange, audio-law selection, data channels and network-address signalling in the expected way.

What changed in SIST ETS 300 143/A1 E1:2003 from the previous edition?

SIST ETS 300 143/A1 E1:2003 is Amendment A1 to ETS 300 143 (1994). The amendment adds A-law/μ-law implementation rules, updates the normative references, revises the BAS capability and command tables, tightens capability-set rules, changes Sequence A timing and behaviour, revises data-channel procedures, and adds optional network-address transmission.

Which standards are used with SIST ETS 300 143/A1 E1:2003?

Standard	What it contributes
ETS 300 144	BAS codes, capability values, commands, data-channel symbols and related procedures
CCITT Recommendation G.711	μ-law coding at 64 kbit/s
CCITT Recommendation G.725	Algorithm for identifying A-law or μ-law PCM on the incoming signal
ITU-T Recommendation H.224	Real-time control protocol for simplex applications; used in MLP/LSD/HSD context
ITU-T Recommendation H.243	Procedures for communication between three or more audiovisual terminals
ITU-T Recommendations T.122, T.123, T.124, T.125	Audiographic conferencing and generic conference control protocols
Draft prETS 300 481	Channel Aggregation Unit procedures and terminal requirements
Draft prETS 300 483	Multipoint Control Unit main functionalities and basic requirements

What does the SIST ETS 300 143/A1 E1:2003 document contain?

The document contains amended text for the core signalling clauses of ETS 300 143, including updated tables for capability sets and command summaries. It also contains procedures for Sequence A, data-channel activation and deactivation, audiographic conferencing support, dummy data handling and optional network-address transmission.

It gives the rules that terminals and MCUs use to decide which BAS values may be signalled, when data channels may be opened, and how audio-law selection is handled during call setup. For implementers, the practical value is in the concrete procedure text and the revised tables that drive interoperability and conformance testing.

SLOVENSKI STANDARD
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/A1 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.

ETS 300 143
AMENDMENT A1
January 1996
Source: ETSI TC-TE Reference: RE/TE-04036
ICS: 33.080
ISDN, audiovisual services
Key words:
This amendment A1 modifies
the European Telecommunication Standard 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
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - [e-mail]
X.400: Internet:
Tel.: [phone] - Fax: [phone]
*
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1996. All rights reserved.

Page 2
ETS 300 143: May 1994/A1: 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.

Page 3
ETS 300 143: May 1994/A1: January 1996
Foreword
This amendment to ETS 300 143 (1994) 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

Page 4
ETS 300 143: May 1994/A1: January 1996
Amendments
The proposed amendments are as follows:
Page 7, clause 1 (Scope), amend the present NOTE to read as NOTE 1 and add the following
second note:
NOTE 2: Terminals in accordance with this ETS can interwork with equipment conforming to
ITU-T Recommendation H.242.
Page 7, clause 2 (Normative references), add the following references:
[7] ITU-T Recommendation H.224 (1994): "A real time control protocol for simplex
applications using the H.221 LSD/HSD/MLP channels".
[8] Draft prETS 300 481: "Terminal Equipment (TE); Integrated Services Digital
Network (ISDN) B-Channel Aggregation; Procedures and terminal
requirements".
[9] ITU-T Recommendation T.122 (1993): "Multipoint communication service for
audiographic and audiovisual conferencing service definition".
[10] ITU-T Recommendation T.123 (1994): "Protocol stacks for audiographic and
audiovisual teleconference applications".
[11] ITU-T Recommendation T.124: "Generic conference control".
[12] Draft ITU-T Recommendation T.125 (1994): "Multipoint communication service
protocol specification".
[13] ITU-T Recommendation H.243 (1993): "Procedures for establishing
communication between three or more audiovisual terminals using digital
channels up to 2 Mbit/s".
[14] 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 (MCUs)".
Page 8, clause 4 (Symbols and abbreviations), amend the following abbreviations to read as
follows and insert the note as given below:
H-MLP High speed MLP logical subchannel
MLP Logical data subchannel named "MLP"
NOTE: MLP was previously referred to the ITU-T Recommendation T.120 Multilayer Protocol,
but now is just a name for the logical subchannel which may contain T.120 or ITU-T
Recommendation H.224 [7] protocol, or Dummy data, see ETS 300 144 [1].
Page 9, subclause 5.1.1 (Audio capabilities), insert the following new paragraphs after the second
paragraph and before table 1 as follows:
At the beginning of the call the default encoding law shall be A-law. If information is available to the
terminal, either by configuration or by user input, as to whether the destination is within a μ-law region,
then this encoding law shall be used after the reception of the ALERTING message or, if the ALERTING
message is not received, the CONNECT message, or in-band signalling, as described in clause 6 has
been initiated.
The information shall be encoded using the μ-law at 64 kbit/s as defined in CCITT Recommendation
G.711 [3].
Page 5
ETS 300 143: May 1994/A1: January 1996
It is the responsibility of the calling terminal to ensure that correct encoding law is used. If no indication on
the coding law is available, the calling terminal shall use the default coding law while monitoring the
statistics of the incoming signal. In order to determine whether the incoming signal was encoded by A-law
or μ-law PCM, the algorithm described in appendix 1 to CCITT Recommendation G.725 [5] shall be used.
Page 11, subclause 5.1.9 (Rules for capability sets), amend the first paragraph to read as follows:
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 other than {Null} shall be repeated within a set (except for MPI values,
see subclause 5.1.2).
Page 12, subclause 5.1.9 (Rules for capability sets), replace table 2 by the new table given below:
Table 2: BAS capabilities that can be included in a valid capability set
Audio Absent or one or more values from
{A-law, μ-law, G.722-48, G.728, Au-ISO} (ETS 300 144 [1], tables 8 & 10)
Video Absent, or
{ [(QCIF plus one MPI value) or (CIF plus two MPI values)] and/or
video-ISO}
Transfer rate Absent (meaning rate = 64 kbit/s only, see also note), 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
Single/multiple channel Absent or {SM-comp} or {6B-H0-com}
Compatibility
Low-Speed Data (LSD) Absent or all relevant values (ETS 300 144 [1], table 8)
High-Speed Data (HSD) Absent or all relevant values (ETS 300 144 [1], table 10)
Low-speed MLP Absent or all relevant values or MLP Set1 or MLP Set2 (ETS 300 144 [1],
tables 8 & 10)
High-speed MLP Absent or all relevant values (ETS 300 144 [1], table 10)
Applications in data channel Absent or all relevant values (ETS 300 144 [1], table 12)
Encryption Absent or present
Multiple-Byte Extension Absent or present
NOTE: When reducing the transfer-rate capability to 64 kbit/s from an higher rate, the value (001)[0]
shall be included.
Page 12, subclause 5.1.9 (Rules for capability sets), amend the first sentence after the two bullet
points of the text to read:
Repetition of the capability set is limited to 10 seconds - see subclause 6.1.1.
Page 13, sublause 5.2.3 (LSD/MLP commands), modify the first paragraph to read as follows:
5.2.3 LSD/MLP commands
Fixed rate LSD/MLP cannot penetrate into Audio bit positions. It can reduce its capacity within the data bit
positions currently occupied.
Page 6
ETS 300 143: May 1994/A1: January 1996
Page 14, subclause 5.2.4 (Rules for commands), replace table 3 with the table given below:
Table 3: Command summary
Attribute Alternative values Default Comments
(value sent last is valid assumed
only)
Audio (000) [0, 4-7, 18-19, 24-31] [18]
Transfer rate (001) [0-16, 23, 24, 26, 29] [0]
(001) [17] See subclause 7.5
Video and (010) [0-3] [0]
other (010) [6, 7] [7]
(010) [16] Cancelled by command in video frame
(010) [17] Expires after fast update completed
(010) [18, 21] [21]
(010) [19, 21] [21]
(010) [20, 21] [21]
(010) [23, 26] [26]
(010) [27, 28] [28]
LSD (011) [0-15, 31] or [0-31] [0] Simultaneous LSD and MLP may be
sent only if {H.224-sim}
MLP (011) [16-30] or [0-31] [16] Has been received - see ITU-T
Recommendation H.224 [7]
HSD **(011) [0, 17-22] [0]
H-MLP **(011) [2-8, 13, 14] [14] **Reached from
Au-ISO **(001) [0-22] [0] escape table (111)[16]
**(001) [23, 24] [24]
**(001) [25-28] [25]
Page 15, subclause 6.1 (Capability exchange (sequence A)), replace by the text given below:
This sequence involves the transmission by both terminals of their current capability sets. Either terminal
may initiate the sequence and there is no problem caused by both doing so simultaneously or nearly
simultaneously. Capability BAS should not be sent unnecessarily when the incoming signal is unframed.
The sequence is used in various procedures, in which the initiating terminal wishes to inform the other of
its own capability set (for example at the start of the call or when the capability set has been changed), or
wishes to check the current capability set of the other (for example in a fault a fault recovery procedure),
or both.
When a terminal activates sequence A during a call, it shall maintain the current mode of multimedia
multiplexing, including FAS and BAS in additional channels if relevant.
A terminal which is intended to interwork with a Channel Aggregation Unit according to draft
prETS 300 481 [8], on receiving the command [capex], shall immediately initiate this sequence A unless a
capability exchange is already in progress: in the latter case, the terminal shall continue the sequence,
ensuring that at least one complete capability set is transmitted after receipt of [capex].
Page 15, subclause 6.1.1 (Initiating terminal), delete the last paragraph and insert the following
text:
If X receives any further capability sets before expiry of timer T , it shall not respond to this by repeating
its own capability set; after expiry of T , it shall respond according to subclause 6.1.2.
Capability sets shall not be sent continuously for more than 10 seconds: if necessary, the sequence sh
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