SIST I-ETS 300 302-3 E1:2003

• Abstract:

  Standardization of electroacoustical characteristics of videotelephony terminals for Integrated Services Digital (ISDN using wideband (CCITT G.722) coding and handset functions.

• 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 300 302-3 ed.1 (1996-09) - Integrated Services Digital Network (ISDN); Videotelephony teleservice; Part 3: Audio aspects - wideband handset

SIST I-ETS 300 302-3 E1:2003 is the Slovenian adoption of ETSI’s Interim European Telecommunication Standard for ISDN videotelephony teleservice, Part 3, focused on audio aspects for a wideband handset. It specifies electroacoustic characteristics for handset functions in videotelephony terminals using ADPCM coding according to CCITT Recommendation G.722 on ISDN basic access, and it is aimed at designers, test labs, quality managers, and buyers of terminal equipment.

What does SIST I-ETS 300 302-3 E1:2003 specify?

SIST I-ETS 300 302-3 E1:2003 specifies the electroacoustic characteristics for videotelephony terminals in the Integrated Services Digital Network (ISDN) when the handset uses wideband coding. The standard concentrates on the audio behavior that matters in real videotelephony use, especially where delay and measurement position differ from ordinary ISDN 7 kHz telephony.

The document is organized into these main parts:

• Scope
• Normative references
• Definitions and abbreviations
• Requirements
• Annex A - informative bibliography

Annex A supports the technical text by pointing to the service descriptions and vocabulary documents used throughout the standard.

What are the key requirements of SIST I-ETS 300 302-3 E1:2003?

SIST I-ETS 300 302-3 E1:2003 largely reuses the technical requirements of I-ETS 300 245-5, but it adapts them for videotelephony handset use. In practice, that means a terminal maker or test lab checks handset audio performance under videotelephony conditions, not only under generic telephony conditions.

Operating mode and test rate

The normal working mode is b2 mode as defined in ETS 300 145. In that mode, speech uses one B-channel at 56 kbit/s or 48 kbit/s audio coding, while video uses 76.8 kbit/s or 68.8 kbit/s. The standard also says that 64 kbit/s coding for CCITT Recommendation G.722 is not mandatory.

For testing, the terminal is measured at 48 kbit/s if that rate is implemented, otherwise at 56 kbit/s. This matters because the standard treats 48 kbit/s as the worse case for several transmission characteristics.

Terminal Coupling Loss

Weighted Terminal Coupling Loss (TCLw) is a key handset requirement. The measured TCLw, corrected to the nominal Sending Loudness Rating (SLR) and Receiving Loudness Rating (RLR), must be at least 40 dB, and it must not drop below 35 dB at any user-controlled volume setting. This is important because it limits unwanted coupling between receive and send paths, which directly affects echo and stability.

Distortion

The standard sets separate Signal to Distortion (S/D) requirements for sending and receiving. The limits depend on tone frequency and input level, and intermediate levels are found by straight-line interpolation between the tabulated break points. For implementers, this means the terminal must preserve speech tone quality across the stated test range, not just at one nominal point.

Noise

The sending direction has an A-weighted noise limit, and the receiving direction has its own A-weighted noise limit at the Ear Reference Point (ERP). These limits keep self-noise from masking speech, which is especially relevant for handset use in quiet and noisy environments.

Delay and lip synchronisation

Delay requirements are taken from I-ETS 300 302-1. For lip synchronisation, the standard gives no normative requirement, but it notes that good synchronisation can be achieved when the audio and video delays differ by less than 25 ms. This is useful for designers checking end-to-end timing.

What terms does SIST I-ETS 300 302-3 E1:2003 define?

SIST I-ETS 300 302-3 E1:2003 defines several terms that shape how the handset is measured and judged.

• ADPCM - Adaptive Differential Pulse Code Modulation, the coding method used for the wideband audio path.
• videotelephony teleservice - A real-time audiovisual service in which speech and moving pictures are exchanged over one or two 64 kbit/s circuit-mode connections.
• telephony 7 kHz teleservice - A real-time 7 kHz speech service used as the comparison point for this handbook-like handset standard.
• Terminal Coupling Loss (TCL) - The frequency-dependent coupling loss between receiving and sending paths inside a terminal.
• Weighted Terminal Coupling Loss (TCLw) - TCL with the weighting of ITU-T Recommendation G.122 applied.
• Ear Reference Point (ERP) - The reference point used for receiver-side acoustic measurements.
• Mouth Reference Point (MRP) - The reference point used for talker-side acoustic measurements.

Who uses SIST I-ETS 300 302-3 E1:2003?

SIST I-ETS 300 302-3 E1:2003 is used by terminal manufacturers, audio engineers, conformity test laboratories, and quality managers working on ISDN videotelephony equipment. It also helps procurement teams and product specifiers compare handset audio performance for terminals intended for the ISDN basic access. In practice, these users apply it when designing, testing, or accepting a videotelephony handset function.

Which standards are used with SIST I-ETS 300 302-3 E1:2003?

Standard	What it contributes
CCITT Recommendation G.722	Defines the 7 kHz audio coding used for the wideband handset.
I-ETS 300 245-5	Provides the technical characteristics and test methods used for TCLw, distortion, and noise.
I-ETS 300 302-1	Gives the related electroacoustic requirements for the PCM version of the same multipart standard.
ETS 300 145	Defines modes of operation and terminal types for videotelephone systems.
ETS 300 264	Defines the videotelephony teleservice service description.

What does the SIST I-ETS 300 302-3 E1:2003 document contain?

The document contains requirement clauses with measurement-based limits for handset performance, including TCLw, distortion, noise, and delay-related behavior. It also includes two limit tables for signal to distortion performance and explains how to interpolate between tabulated points.

Several requirements point to external test methods in I-ETS 300 245-5, so the standard is meant to be used with a test procedure, not as a stand-alone theory document. Annex A provides the bibliography that links the standard to service descriptions, vocabulary documents, and the video codec reference used to interpret the timing note on lip synchronisation.

SLOVENSKI STANDARD
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Daljinske storitve:
videotelefonija – 3. del: Zvokovni vidiki – Širokopasovna pogovorka
Integrated Services Digital Network (ISDN); Videotelephony teleservice; Part 3: Audio
aspects - wideband handset
Ta slovenski standard je istoveten z: I-ETS 300 302-3 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 300 302-3
TELECOMMUNICATION September 1996
STANDARD
Source: ETSI TC-TE Reference: DI/TE-04008.3
ICS: 33.080
Key words: ISDN, videotelephony terminal, audio, 7 kHz
Integrated Services Digital Network (ISDN);
Videotelephony teleservice;
Part 3: Audio aspects - wideband handset
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 300 302-3: 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 300 302-3: September 1996
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .7
3.1 Definitions .7
3.2 Abbreviations .8
4 Requirements.8
4.1 General .8
4.2 Terminal Coupling Loss .8
4.3 Distortion.9
4.3.1 Sending .9
4.3.2 Receiving.9
4.4 Noise.10
4.4.1 Sending .10
4.4.2 Receiving.10
4.5 Delay.10
4.6 Lip synchronisation .10
Annex A (informative): Bibliography.11
History.12

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I-ETS 300 302-3: September 1996
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I-ETS 300 302-3: September 1996
Foreword
Part 3 of 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 an ETS, have it's life extended for a further
two years, be replaced by a new version, or be withdrawn.
This I-ETS is part 3 of a multipart standard covering "Integrated Services Digital Network (ISDN);
Videotelephony teleservice", as described below.
Part 1: "Electroacoustic characteristics for handset telephony function when using Pulse Code
Modulation encoding".
Part 2: "Audio aspects - Pulse Code Modulation (PCM) A-law loudspeaking and handsfree".
Part 3: "Audio aspects - wideband handset".
Part 4: "Audio aspects - wideband coding and loudspeaking or handsfree function".
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

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I-ETS 300 302-3: September 1996
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I-ETS 300 302-3: September 1996
1 Scope
This Interim European Telecommunication Standard (I-ETS) specifies the electroacoustic characteristics
for handset functions implemented in videotelephony terminals intended for use in the videotelephone
teleservice in the Integrated Services Digital Network (ISDN) using Adaptive Differential Pulse Code
Modulation (ADPCM) encoding according to CCITT Recommendation G.722 [1]. Those terminals will be
connected to the basic access of the coincident S and T reference point of the ISDN.
The videotelephony teleservice in the ISDN is defined in ETS 300 264 (see annex A).
The requirements of this I-ETS specify those characteristics which deviate from those of an ISDN 7 kHz
telephony terminal. Those deviations are due to conditions which are special for videotelephony
applications (e.g. delay, measurement position). The corresponding requirements for an ISDN 7 kHz
telephony handset terminal can be found in I-ETS 300 245-5 [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] CCITT Recommendation G.722 (1990): "7 kHz audio coding within 64 kbit/s".
[2] I-ETS 300 245-5 (1995): "Technical characteristics for telephony terminals; Part
5: Wide band (7 kHz) handset telephony".
[3] I-ETS 300 302-1 (1994): "Integrated Services Digital Network (ISDN);
Videotelephony teleservice; Part 1: Electroacoustic characteristics for telephony
function when using Pulse Code Modulation (PCM) encoding".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this part of the I-ETS, the relevant definitions in CCITT Recommendations P.10 and
G.7
...