SIST I-ETS 300 302-1 E2:2003

• Abstract:

  To prepare an amendment sheet to, or a new edition of I-ETS 300 302-1 where use of the speech coding algorithms specified in ITU-T Recommendation G.728 is included, and the references are updated to reflect the re-organization of the ISDN telephony standards.

• 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 300 302-1 ed.2 (1996-11) - Integrated Services Digital Network (ISDN); Videotelephony teleservice; Part 1: Electroacoustic characteristics for 3,1 kHz bandwidth handset terminals

SIST I-ETS 300 302-1 E2:2003 is the Slovenian adoption of ETSI I-ETS 300 302-1 Edition 2, an Interim European Telecommunication Standard for ISDN videotelephony handset terminals. It specifies electroacoustic characteristics for 3,1 kHz bandwidth handset terminals used in the videotelephony teleservice, including PCM and optional LD-CELP speech coding. The document is aimed at terminal designers, test laboratories, quality managers and approval teams who need to check whether a handset terminal behaves correctly on the ISDN basic access.

What does SIST I-ETS 300 302-1 E2:2003 specify?

SIST I-ETS 300 302-1 E2:2003 specifies the electroacoustic characteristics of 3,1 kHz bandwidth handset telephony functions implemented in videotelephony terminals on the ISDN basic access at the coincident S and T reference point. The standard focuses on the characteristics that differ from ordinary ISDN 3,1 kHz telephony because of videotelephony conditions such as framing and delay.

The document is organized into scope, normative references, definitions and abbreviations, the requirements for Mode 0U and framed transmission in PCM encoding, an optional section for LD-CELP encoding, and two annexes.

Part	What it covers
Clause 3	Definitions and abbreviations used in the standard
Clause 4	Mode 0U characteristics, including coding-law selection
Clause 5	Framed transmission in PCM encoding and the main electroacoustic requirements
Clause 6	Additional requirements when LD-CELP encoding is implemented
Annex A	Normative test methods
Annex B	Bibliography

Clauses 4 and 5 apply to all videotelephonic terminals covered by the standard. Clause 6 applies only when the optional LD-CELP speech coding mode is implemented.

What are the key requirements of SIST I-ETS 300 302-1 E2:2003?

Encoding and operating mode selection

SIST I-ETS 300 302-1 E2:2003 requires Mode 0U to be used at the beginning of a call, with A-law as the default encoding law. If in-band signalling shows that the distant terminal supports μ-law only, the terminal shall use μ-law at 64 kbit/s.

In practice, this means the calling terminal has to select the correct speech coding law from signalling information and, if needed, from signal monitoring. That affects interoperability between terminals and the way test equipment must be set up.

Main PCM electroacoustic characteristics

SIST I-ETS 300 302-1 E2:2003 sets requirements for sensitivity-frequency response, sending and receiving loudness ratings, sidetone, terminal coupling loss, distortion, gain variation, out-of-band signals and noise under framed PCM transmission. The standard points most of these checks to the test methods in I-ETS 300 245-2, with Listener sidetone and TCLw tested by methods in its own Annex A.

In practice, the terminal must be measured as a whole, not just as a codec. Manufacturers and labs have to verify the acoustic path, the electrical path and the interaction between them.

Loudness, coupling loss and delay

SIST I-ETS 300 302-1 E2:2003 requires the weighted Terminal Coupling Loss (TCLw) to remain above the specified minimum values and sets the maximum total delay from mouth reference point to ear reference point at less than 375 ms. Lip synchronization has no normative requirement, but the document gives guidance for good synchronization.

This matters because users notice echo, sidetone, speech latency and audio-video mismatch directly. The delay limit and TCLw checks are there to keep speech usable in a live videotelephony call.

Optional LD-CELP mode

SIST I-ETS 300 302-1 E2:2003 allows an optional LD-CELP speech coding mode at 16 kbit/s. To claim conformance, the terminal has to meet G.728 conformance and keep the difference in calculated SLR and RLR within 0,5 dB compared with the PCM-based values.

For a buyer or tester, this means LD-CELP is an extra mode with its own proof of compliance, not just a codec flag. If a product offers it, both codec conformance and the acoustic impact must be checked.

What terms does SIST I-ETS 300 302-1 E2:2003 define?

• digital interface - The interface at the coincident S and T reference point.
• LRGP - Loudness Rating Guard-Ring Position, the handset position used in the test setup.
• service channel - The sub-channel that carries end-to-end signalling in the 64 kbit/s channel.
• Terminal Coupling Loss (TCL) - The frequency-dependent coupling loss between the receiving and sending ports of a terminal.
• Weighted Terminal Coupling Loss (TCLw) - TCL calculated with the weighting from G.122.
• videotelephony teleservice - A real-time audiovisual service where speech and moving pictures are exchanged over one or two 64 kbit/s circuit-mode connections.
• SLR / RLR - Sending Loudness Rating and Receiving Loudness Rating, the loudness measures used to judge speech level at the sending and receiving paths.

Who uses SIST I-ETS 300 302-1 E2:2003?

SIST I-ETS 300 302-1 E2:2003 is used by terminal manufacturers, test laboratories, certification or approval bodies, and telecom quality teams working on ISDN videotelephony handset terminals. They use it to design the speech path, set up conformance tests, compare loudness and coupling-loss results, and document compliance for products that connect at the ISDN basic access.

What changed in SIST I-ETS 300 302-1 E2:2003 from the previous edition?

SIST I-ETS 300 302-1 E2:2003 corresponds to Edition 2 of I-ETS 300 302-1. The scope states that this edition was prepared to include the use of the speech coding algorithms specified in ITU-T Recommendation G.728 and to update the references to reflect the re-organization of the ISDN telephony standards.

Which standards are used with SIST I-ETS 300 302-1 E2:2003?

The standard relies on several named references for codecs, test methods and definitions:

Reference	What it contributes
CCITT Recommendation G.711	PCM coding, including A-law and μ-law
I-ETS 300 245-2	Main test methods and related PCM handset requirements
I-ETS 300 245-8	Speech transmission characteristics for LD-CELP at 16 kbit/s
CCITT Recommendation G.728	LD-CELP speech coding at 16 kbit/s
ETS 300 145	Videotelephony systems, terminal equipment and operating modes
ETS 300 144	Frame structure and service-channel position
ETS 300 111	Telephony 3,1 kHz teleservice description
ETS 300 143	In-band signalling procedures
ETS 300 267-1	DSS1 protocol for telephony and videotelephony teleservices
ITU-T Recommendation P.64	Sensitivity and frequency-characteristic methods, and LRGP
ITU-T Recommendation P.31	Transmission characteristics for digital telephones
ITU-T Recommendation P.57	Artificial ears
ITU-T Recommendation P.79	Loudness-rating calculation
CCITT Recommendation G.122	Weighting for TCLw
ISO 3	Preferred numbers used for test frequencies
IEC 225	Octave and third-octave band filters

What does the SIST I-ETS 300 302-1 E2:2003 document contain?

SIST I-ETS 300 302-1 E2:2003 contains requirement clauses for coding-law selection, framed transmission, loudness ratings, sidetone, coupling loss, distortion, noise, delay and optional LD-CELP operation. It also contains a full annex of test methods for delay, Listener SideTone Rating and TCLw.

Annex A describes the test setups and measurement conditions, including handset positioning at the LRGP, use of an artificial ear, diffuse sound-field conditions for LSTR, and free-field conditions for TCLw. These are the procedures a lab uses to turn the performance clauses into repeatable measurements.

Annex B is a bibliography that points readers to related telecom, acoustics and video-codec documents used around the standard.

SLOVENSKI STANDARD
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Integrated Services Digital Network (ISDN); Videotelephony teleservice; Part 1:
Electroacoustic characteristics for 3,1 kHz bandwidth handset terminals
Ta slovenski standard je istoveten z: I-ETS 300 302-1 Edition 2
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 300 302-1
TELECOMMUNICATION November 1996
STANDARD Second Edition
Source: ETSI TC-TE Reference: RI/TE-04042
ICS: 33.020
Key words: ISDN, telephony, terminal, video
Integrated Services Digital Network (ISDN);
Videotelephony teleservice;
Part 1: Electroacoustic characteristics for
3,1 kHz bandwidth handset terminals
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 300 302-1: 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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I-ETS 300 302-1: November 1996
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .9
4 Mode 0U characteristics.9
4.1 Default encoding law.9
4.2 A-law encoding .9
4.3 μ-law encoding.10
5 Characteristics for framed transmission in PCM encoding .10
5.1 General .10
5.1.1 Encoding .10
5.1.2 Relative level .10
5.1.3 Volume control .11
5.2 Sensitivity - frequency response .11
5.3 Sending and Receiving Loudness Rating (SLR and RLR) .11
5.4 Sidetone.11
5.4.1 Talker sidetone.11
5.4.2 Listener sidetone .11
5.5 Terminal Coupling Loss (TCL).11
5.5.1 TCLw .11
5.5.2 Stability loss.11
5.6 Distortion.11
5.7 Variation of gain with input level.11
5.8 Out-of-band signals .12
5.9 Noise.12
5.10 Acoustic shock.12
5.11 Absolute delay.12
5.12 Lip synchronization .12
6 Characteristics for framed transmission in LD-CELP encoding.12
6.1 General .12
6.2 Sensitivity.12
6.2.1 Sending .12
6.2.2 Receiving.13
Annex A (normative): Test methods.14
A.1 General conditions for testing.14
A.2 Delay .14
A.2.1 Sending.14
A.2.2 Receiving .14

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I-ETS 300 302-1: November 1996
A.3 Listener SideTone Rating (LSTR) . 14
A.4 Weighted Terminal Coupling Loss (TCLw). 15
Annex B (informative): Bibliography . 16
History. 17

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I-ETS 300 302-1: November 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).
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 a European Telecommunication Standard
(ETS), have its life extended for a further 2 years, be replaced by a new version of the I-ETS or, be
withdrawn.
This I-ETS is part 1 of a multipart standard covering "Integrated Services Digital Network (ISDN);
Audiovisual services in-band signalling testing", as described below:
Part 1: "Electroacoustic characteristics for 3,1 kHz bandwidth handset terminals";
Part 2: "Electroacoustic characteristics for 3.1 kHz bandwidth loudspeaking and handsfree
terminals";
Part 3: "Wideband handset";
Part 4: "Wideband coding loudspeaking and handsfree function".
Proposed announcement date
Date of adoption of this I-ETS: 25 October 1996
Date of latest announcement of this I-ETS (doa): 28 February 1997

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I-ETS 300 302-1: November 1996
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I-ETS 300 302-1: November 1996
1 Scope
This part of the Interim European Telecommunication Standard (I-ETS) specifies the electroacoustic
characteristics for 3,1 kHz bandwidth handset telephony functions implemented in videotelephony
terminals. Those terminals are intended for use in the videotelephony teleservice and connected to the
basic access of the coincident S and T reference point of the Integrated Services Digital Network (ISDN)
using either Pulse Code Modulation (PCM) encoding according to CCITT Recommendation G.711 [1],
A-law and μ-law or Low Delay code-Excited Linear Prediction (LD-CELP) coding at 16 kbit/s as specified
in CCITT Recommendation G.728 [21].
The videotelephony teleservice in the ISDN is defined in ETS 300 264 (see annex B).
The requirements of this I-ETS specify those characteristics which deviate from those which an
ISDN 3,1 kHz telephony terminal needs to meet due to conditions which are special for the videotelephony
application (e.g. delay, framing). The corresponding requirements to an ISDN 3,1 kHz telephony terminal
can be found in I-ETS 300 245-2 [2] for PCM encoding and in I-ETS 300 245-8 [20] for LD-CLP encoding.
The requirements of clauses 4 and 5 are applicable to all videotelephonic terminals and clause 6 is
applicable when the optional LD-CELP encoding is implemented.
The relevant test methods are described in I-ETS 300 245-2 [2], and in I-ETS 300 245-8 [20].
NOTE: Type approval requirements for the 3,1 kHz telephony (CCITT Recommendation
G.711 [1], A-law) function of a videotelephony terminal can be found in TBR 8 (see
annex B).
2 Normative references
This I-ETS incorporates by dated or undated reference, provision 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 referenced to applies.
[1] CCITT Recommendation G.711 (1988): "Pulse code modulation (PCM) of voice
frequencies".
[2] I-ETS 300 245-2: "Integrated Services Digital Network (ISDN); Technical
characteristics of telephony terminals - Part 2: Pulse Code Modulation (PCM)
A-law, handset telephony".
[3] CCITT Recommendation G.122 (1988): "Influence of national systems on
stability talker echo in international connections".
[4] ETS 300 111 (1992): "Integrated Services Digital Network (ISDN); Telephony
3,1 kHz teleservice - Service description".
[5] ETS 300 145: "Integrated Services Digital Network (ISDN); Audiovisual
teleservices - Videotelephony systems and terminal equipment operating on one
or two 64 kbit/s channels".
[6] 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 inband signalling".
[7] ITU-T Recommendation P.64 (1993): "Determination of sensitivity/frequency
characteristics of local telephone systems".
[8] CCITT Recommendation G.701 (1988): "Vocabulary of digital transmission and
multiplexing, and pulse code modulation (PCM) terms".
[9] CCITT Recommendation I.112 (1988): "Vocabulary of terms for ISDNs".

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I-ETS 300 302-1: November 1996
[10] ITU-T Recommendation P.10 (1993): "Vocabulary of terms on telephone
transmission quality and telephone sets".
[11] 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".
[12] CCITT Recommendation G.725 (1988): "System aspects for the use of the
7 kHz audio codec within 64 kbit/s".
[13] ETS 300 267-1: "Integrated Services Digital Network (ISDN); Telephony 7 kHz
and videotelephony teleservices - Digital Subscriber Signalling System No. one
(DSS1) protocol - Part 1: Protocol specification".
[14] ITU-T Recommendation P.31 (1993): "Transmission characteristics for digital
telephones".
[15] CCITT Recommendation G.101 (1988): "The transmission plan".
[16] ISO 3 (1977): "Preferred numbers - Series of preferred numbers".
[17] ITU-T Recommendation P.57 (1993): "Artificial ears".
[18] IEC 225: "Octave, half-octave and third-octave band filters intended for the
analysis of sound and vibrations".
[19] ITU-T Recommendation P.79 (1993): "Calculation of loudness ratings for
telephone sets".
[20] I-ETS 300 245-8 (1996): "Integrated Services Digital Network (ISDN); Technical
characteristics of Telephony Terminals, Part 8 - Speech transmission
characteristics when using low-delay code-excited linear prediction coding at
16 kbit/s".
[21] CCITT Recommendation G.728 (1992): "Coding of speech at 16 kbit/s using low
delay code excited linear prediction".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this part of the I-ETS, the following definitions apply:
digital interface: The interface at the coincident S and T reference point.
Loudness Rating Guard-Ring Position (LRGP): This position is defined in
ITU-T Recommendation P.64 [7].
modes of operation: For the videotelephony teleservice in the ISDN, the modes of operation are defined
in ETS 300 145 [5].
service channel: A sub-channel which provides end-to-end signalling in the 64 kbit/s channel. The
service channel consists of the eighth bit of each byte. The structure of a 64 kbit/s channel (B-channel)
and the position of the service channel is described in ETS 300 144 [6].
telephony 3,1 kHz teleservice: A description of the telephony 3,1 kHz teleservice in the ISDN is to be
found in ETS 300 111 [4].
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I-ETS 300 302-1: November 1996
Terminal Coupling Loss (TCL): The frequency dependent coupling loss between the receiving port and
the sending port of a terminal due to:
− acoustical coupling at the user interface;
− electrical coupling due to crosstalk in the handset cord or within the electrical circuits;
− seismic coupling through the mechanical parts of the terminal.
NOTE 1: The receiving port and the sending port of a digital voice terminal is a 0 dBr point.
NOTE 2: The coupling at the user interface depends on the conditions of use.
terminal types: For the videotelephony teleservice in the ISDN, terminal types are defined in
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. It is characterized by
the transmission of moving pictures simu
...