SIST I-ETS 300 245-8 E1:2003

• Abstract:

  Specification of characteristics for digital telephony terminals using the 16 kbit/s speech coding algorithm currently being developed by ITU TS (previously CCITT) under Q21/15 (previously Q21/XV).

• 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 300 245-8 ed.1 (1996-01) - Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals; Part 8: Speech transmission characteristics when using Low-Delay Code-Excited Linear Prediction (LD-CELP) coding at 16 kbit/s

SIST I-ETS 300 245-8 E1:2003 is the Slovenian adoption of ETSI I-ETS 300 245-8 Edition 1. It specifies the speech transmission characteristics for ISDN telephony terminals that use Low-Delay Code-Excited Linear Prediction (LD-CELP) coding at 16 kbit/s, together with the related test methods and conformance checks.

This part is aimed at terminals at the ISDN basic access coincident S and T reference point. In practice, it helps manufacturers, test laboratories, and purchasers confirm whether a telephony terminal with an optional LD-CELP mode behaves as intended.

What does SIST I-ETS 300 245-8 E1:2003 specify?

SIST I-ETS 300 245-8 E1:2003 specifies the technical characteristics for telephony terminals using LD-CELP at 16 kbit/s, and it applies together with I-ETS 300 245-1. The document focuses on the limited set of characteristics that can be affected by the codec implementation.

It also states what is outside its practical reach: the version described here does not cover measurements on receivers in handsets with low acoustic output impedance.

Annex	What it covers
Annex A	Normative test specifications, including test conditions, equipment, interfaces, calibration accuracy, and delay measurements
Annex B	Informative bibliography

What are the key requirements of SIST I-ETS 300 245-8 E1:2003?

Clause 4 requires the call control function to meet I-ETS 300 245-1. For a terminal to conform, the codec-specific part cannot be considered on its own - the general ISDN terminal requirements still apply.

Clause 5 says the default speech encoding for all telephony terminals is PCM A-law at 64 kbit/s as defined in G.711. The LD-CELP requirements apply only when the terminal is operating in its optional 16 kbit/s mode.

Clause 5 also sets the interface reference level: the digital interface is treated as a 0 dBr point. That matters because measurements must be made against a common level reference.

Clause 5.1 says the requirements apply for all positions of the user-controlled receiving volume control, if the terminal has one. So a supplier cannot test only the most favorable volume setting.

Clause 5.2 ties conformance to three things:

• in PCM A-law mode, the terminal must meet I-ETS 300 245-2 or I-ETS 300 245-3, depending on whether it is a handset or loudspeaking/hands free terminal;
• conformance to G.728 must be verified, or declared by the supplier if access to the codec is not available;
• the specific LD-CELP-sensitive characteristics in subclauses 5.2.2 to 5.2.4 must be met.

The sensitivity limits in clause 5.2.2 are expressed as differences between LD-CELP operation and PCM A-law operation. In practice, this means the terminal is compared against its own A-law behavior, not against an external absolute target. The sending and receiving loudness ratings are each limited to a very small change.

Clause 5.2.4 limits total delay from the Mouth Reference Point (MRP) to the Ear Reference Point (ERP) to 10 ms. That is important for conversational quality, because excessive delay makes talker interaction feel unnatural.

Clause 6 refers power feeding back to I-ETS 300 245-1, and clause 7 gives no normative handset requirements but directs audible alerting module requirements back to Part 1.

What terms does SIST I-ETS 300 245-8 E1:2003 define?

• Digital interface - the B-channels available at the coincident S and T reference point in an ISDN basic access.
• Hands free (telephone) set - a telephone set that can be used without a handset, using a loudspeaker and amplifier as the receiver.
• Loudspeaking (telephone) set - a handset telephone that uses a loudspeaker and amplifier as the receiver.
• Loudness rating - a decibel measure of the loudness performance of a telephone connection or part of one.
• Pulse Code Modulation (PCM) - a process where samples are quantified and encoded into a digital signal.
• Telephony 3,1 kHz teleservice - bidirectional speech transmission with 3,1 kHz audio bandwidth.
• Sending Loudness Rating (SLR) - the sending-side loudness measure used in the requirements.
• Receiving Loudness Rating (RLR) - the receiving-side loudness measure used in the requirements.

Who uses SIST I-ETS 300 245-8 E1:2003?

SIST I-ETS 300 245-8 E1:2003 is used by manufacturers of ISDN telephony terminals, especially those adding an optional LD-CELP speech mode. It is also used by compliance test laboratories that need repeatable test conditions and by engineering teams verifying codec behavior, loudness stability, and delay.

It is relevant when specifying, designing, or checking telephony terminals for ISDN basic access. Buyers and quality managers use it to compare supplier claims against a defined technical test basis.

Which standards are used with SIST I-ETS 300 245-8 E1:2003?

Reference	Contribution
CCITT Recommendation G.728	Defines the 16 kbit/s LD-CELP speech coding algorithm
I-ETS 300 245-1	Provides the general ISDN telephony terminal requirements, power feeding, and test environment basis
CCITT Recommendation G.711	Defines PCM A-law encoding used for the bitstreams and default speech mode
I-ETS 300 245-2	Gives handset PCM A-law speech transmission characteristics and related tests
I-ETS 300 245-3	Gives loudspeaking and hands free PCM A-law speech transmission characteristics and related tests
CCITT Recommendation G.101	Defines the 0 dBr reference point
TBR 3	Specifies connection requirements to ISDN basic access for test equipment and terminal attachment
ETS 300 144	Gives the framing and bit assignment used for the 16 kbit/s coder access
ITU-T Recommendation P.51	Specifies the artificial mouth used in testing
ITU-T Recommendation P.57	Specifies the artificial ear used in testing
IEC Publication 651	Specifies the sound level meter type used in testing
CCITT Recommendation G.712	Provides the transmission performance benchmark used for reference codec quality

What does the SIST I-ETS 300 245-8 E1:2003 document contain?

The document contains a short set of clauses covering scope, references, definitions, call control, speech transmission characteristics, power feeding, and physical modules. Annex A gives the full normative test setup, including environment, power supply limits, test signals, access to the 16 kbit/s bitstream, reference codec conditions, analogue interface details, calibration accuracy, and the delay test method.

Annex A also includes a codec filter figure and a calibration accuracy table, which are used to make measurements repeatable. Annex B is a bibliography for background documents such as handset guidance, measurement vocabulary, and the ISDN telephony 3,1 kHz teleservice description.

SLOVENSKI STANDARD
01-december-2003
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Integrated Services Digital Network (ISDN); Technical characteristics of telephony
terminals; Part 8: Speech transmission characteristics when using Low-Delay Code-
Excited Linear Prediction (LD-CELP) coding at 16 kbit/s
Ta slovenski standard je istoveten z: I-ETS 300 245-8 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 300 245-8
TELECOMMUNICATION January 1996
STANDARD
Source: ETSI TC-TE Reference: T/TE 10-07(H)
ICS: 33.080
ISDN, telephony terminals, LD-CELP coding
Key words:
Integrated Services Digital Network (ISDN);
Technical characteristics of telephony terminals;
Part 8: Speech transmission characteristics when using
Low-Delay Code-Excited Linear Prediction (LD-CELP)
coding at 16 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.

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I-ETS 300 245-8: 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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I-ETS 300 245-8: January 1996
Contents
Foreword .5
Introduction.5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .8
4 Call control function.8
5 Speech transmission characteristics.8
5.1 General .8
5.1.1 Default speech encoding.8
5.1.2 LD-CELP speech encoding.9
5.1.3 Relative level .9
5.1.4 Volume control .9
5.2 Speech performance characteristics .9
5.2.1 Introduction.9
5.2.2 Sensitivity .9
5.2.2.1 Sending.9
5.2.2.2 Receiving.9
5.2.3 Acoustic shock .9
5.2.4 Delay .10
6 Power feeding .10
6.1 General conditions.10
7 Physical modules .10
7.1 Handset.10
7.2 Audible alerting module .10
Annex A (normative): Test specifications.11
A.1 General conditions for testing.11
A.1.1 Environment for tests.11
A.1.2 Power supply limitations .11
A.1.3 Test signals.11
A.1.4 Test equipment interface .11
A.1.4.1 General.11
A.1.4.2 Access to 16 kbit/s bitstream .11
A.1.5 Test equipment requirements.11
A.1.5.1 Electro-acoustic equipment.11
A.1.5.2 Test equipment for the digital interface .12
A.1.5.2.1 General.12
A.1.5.2.2 Codec specification .12
A.1.5.2.3 Analogue interface.12
A.1.5.2.4 Definition of 0 dBr point .13
A.1.5.2.5 Direct digital processing approach .13
A.1.6 Accuracy of calibrations.13
A.2 Speech transmission requirements testing .13
A.2.1 Delay.13

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I-ETS 300 245-8: January 1996
Annex B (informative): Bibliography . 15
History. 16

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I-ETS 300 245-8: January 1996
Foreword
Part 8 of this Interim European Telecommunication Standard (I-ETS) was produced by the Terminal
Equipment (TE) Technical Committee of the European Telecommunications Standards Institute (ETSI).
An ETSI draft standard may be given I-ETS status as it is regarded either 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, at first, to three years after which it can be converted into a full European Telecommunication
Standard (ETS), have its life extended for a further two years, be replaced by a new version of the I-ETS
or, finally, be withdrawn.
This is the eighth Part of an I-ETS which comprises eight Parts:
Part 1: General.
Part 2: PCM A-law, handset telephony.
Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and hands free telephony.
Part 4: Interface for additional equipment.
Part 5: Wideband (7 kHz) handset telephony.
.
Part 6: Wideband (7 kHz), loudspeaking and hands free telephony.
Part 7: Locally generated information tones.
Part 8: Speech transmission characteristics when using Low-Delay Code-Excited Linear
Prediction (LD-CELP) coding at 16 kbit/s.
Proposed announcement date
Date of adoption of this I-ETS: 12 January 1996
Date of latest announcement of this I-ETS (doa): 30 April 1996
Introduction
The speech coding algorithm specified in CCITT Recommendation G.728 [1] is based on a digital
bitstream encoded according to CCITT Recommendation G.711 [3]. The terminal applications of the
CCITT Recommendation G.728 [1] algorithm are based on the framing structure specified in ETS 300 144
[8]. These terminals will be able to work in mode a0, i.e. using CCITT Recommendation G.711 [3]
encoding. The characteristics to be specified in this I-ETS can therefore be verified by:
- testing the audio characteristics of the terminal when it is working in mode a0;
- verifying that the speech coding algorithm is conforming to CCITT Recommendation G.728 [1].
The characteristics specified in this I-ETS are based on the principle where a limited number are specified
to test the overall characteristics of a terminal where the CCITT Recommendation G.728 [1] algorithm is
implemented.
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I-ETS 300 245-8: January 1996
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I-ETS 300 245-8: January 1996
1 Scope
Part 8 of this I-ETS specifies the technical characteristics for telephony terminals to be used at the basic
access for the coincident S and T reference point of the Integrated Services Digital Network (ISDN) when
using Low-Delay Code-Excited Linear Prediction (LD-CELP) coding at 16 kbit/s as specified in CCITT
Recommendation G.728 [1]. This Part applies in conjunction with I-ETS 300 245-1 [2].
The input and output bitstreams to and from the LD-CELP are encoded using the Pulse Code Modulation
(PCM) A-law encoding specified in CCITT Recommendation G.711 [3]. The speech transmission
characteristics of a handset terminal when using PCM A-law encoding are specified in I-ETS 300 245-2
[4], and the speech transmission characteristics of a hands free or loudspeaking terminal when using
PCM A-law are specified in I-ETS 300 245-3 [5]. The requirements of this Part are restricted to the
minimum set of characteristics where the implementation of the LD-CELP codec may influence the
speech transmission characteristics.
The present version of this Part does not cover measurements on receivers (in handsets) with low
acoustic output impedance.
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.728 (1992): "Coding of speech at 16 kbit/s using
low-delay code-excited linear prediction".
[2] I-ETS 300 245-1: "Integrated Services Digital Network (ISDN); Technical
characteristics of telephony terminals, Part 1: General".
[3] CCITT Recommendation G.711 (1988): "Pulse code modulation (PCM) of voice
frequencies".
[4] I-ETS 300 245-2: "Integrated Services Digital Network (ISDN); Technical
characteristics of telephony terminals, Part 2: PCM A-law handset telephony".
[5] I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical
characteristics of telephony terminals, Part 3: Pulse Code Modulation (PCM)
A-law, loudspeaking and hands free telephony".
[6] CCITT Recommendation G.101 (1988): "The transmission plan".
[7] TBR 3 (1995): "Integrated Services Digital Network (ISDN); Attachment
requirements for terminal equipment to connect to an ISDN using ISDN basic
access".
[8] 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".
[9] ITU-T Recommendation P.51 (1993): "Artificial mouth".
[10] ITU-T Recommendation P.57 (1993): "Artificial ears".
[11] IEC Publication 651: "Sound level meters".
[12] CCITT Recommendation G.712 (1992): "Transmission performance
characteristics of pulse code modulation".

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I-ETS 300 245-8: January 1996
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this Part of the I-ETS, the following definitions apply:
digital interface: The B-channels available at the coincident S and T reference point at an ISDN basic
access.
hands free (telephone) set: A telephone set using a loudspeaker associated with an amplifier as a
telephone receiver and which may be used without a handset [ITU-T Recommendation P.10 (1993
...