SIST I-ETS 300 302-1 E1:2003

• Abstract:

  Standardization of electroacoustical characteristics of videotelephony terminals for Integrated System Digital Network using PCM A-law 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 300 302-1 ed.1 (1994-12) - Integrated Services Digital Network (ISDN); Videotelephony teleservice; Part 1: Electroacoustic characteristics for handset telephony function when using Pulse Code Modulation (PCM) encoding

SIST I-ETS 300 302-1 E1:2003 is the Slovenian adoption of ETSI I-ETS 300 302-1 Edition 1, an interim European telecommunications standard for Integrated Services Digital Network (ISDN) videotelephony. It specifies electroacoustic characteristics and test methods for handset telephony functions in videotelephony terminals that use Pulse Code Modulation (PCM) encoding.

What does SIST I-ETS 300 302-1 E1:2003 specify?

SIST I-ETS 300 302-1 E1:2003 specifies the electroacoustic characteristics for handset telephony functions in videotelephony terminals on the ISDN basic access. It focuses on the parts of the handset performance that are specific to videotelephony, such as delay and framing, and uses PCM with G.711 A-law and μ-law coding.

The document is organized into five clauses and two annexes.

Annex	What it covers
Annex A	Normative test methods
Annex B	Informative bibliography

The foreword also places this standard in a planned six-part I-ETS series, with Parts 2 to 6 covering loudspeaking, wideband, and low-bitrate variants.

What are the key requirements of SIST I-ETS 300 302-1 E1:2003?

SIST I-ETS 300 302-1 E1:2003 sets the handset coding, acoustic performance, and delay conditions that a videotelephony terminal has to meet in practice. The most important requirements are in Clauses 4 and 5, with Annex A giving the test methods.

Coding and operating mode

Clause 4 states that Mode 0U is the default at call start and that the default encoding law is A-law. If the distant terminal indicates μ-law only, the terminal uses μ-law at 64 kbit/s. In practice, the calling terminal has to manage the coding law correctly during signalling and fallback.

Normal mode and test mode

Clause 5 identifies mode b1 as the normal working mode, with speech at 56 kbit/s in one B-channel and video at 68.8 kbit/s. For electroacoustic testing, the standard says tests should be performed in mode a0, where speech is carried at 64 kbit/s. That matters because the measured audio performance should reflect the encoding conditions, not the video-related traffic split.

Reference level and user volume control

Clause 5.1.2 sets the digital interface at a 0 dBr point. Clause 5.1.3 says the requirements apply to all positions of any user-controlled receiving volume control unless stated otherwise. In practice, the terminal must stay within specification across the usable volume range.

Acoustic characteristics to be verified

Clauses 5.2 to 5.9 cover sensitivity and frequency response, Sending and Receiving Loudness Rating (SLR and RLR), sidetone, Terminal Coupling Loss (TCL), stability loss, distortion, gain variation, out-of-band signals, and noise. These are checked using the named methods in ETS 300 085, I-ETS 300 245-2, and Annex A. For a tester or buyer, this means the terminal must be measured, not just designed, for echo-related and audio-quality behavior.

Terminal coupling loss and delay

Clause 5.5.1 requires Weighted Terminal Coupling Loss (TCLw) of at least 40 dB when corrected to nominal SLR and RLR, and at least 35 dB for all positions of the user-controlled volume control. Clause 5.11 limits the total delay from the Mouth Reference Point (MRP) to the Ear Reference Point (ERP) through the digital interface to less than 375 ms. These limits matter because they affect echo, sidetone, and conversational naturalness.

Safety and lip synchronization

Clause 5.10 treats acoustic shock as a safety matter linked to the Low Voltage Directive (LVD). Clause 5.12 states that there are no normative requirements for lip synchronization, although the note gives a practical timing target for good audio-video alignment.

What terms does SIST I-ETS 300 302-1 E1:2003 define?

• Digital interface - The interface at the coincident S and T reference point.
• Loudness Rating Guard-ring Position (LRGP) - The handset position used for the loudness-related tests, as defined in ITU-T Recommendation P.64.
• Service channel - The sub-channel that carries end-to-end signalling in the 64 kbit/s channel.
• Terminal Coupling Loss (TCL) - The frequency-dependent loss between the receiving and sending ports caused by acoustic, electrical, and mechanical coupling.
• Weighted Terminal Coupling Loss (TCLw) - TCL calculated with the weighting defined in CCITT Recommendation G.122.
• Modes of operation - The videotelephony modes defined in ETS 300 145.
• Videotelephony teleservice - The ISDN videotelephony service described in ETS 300 264.

Who uses SIST I-ETS 300 302-1 E1:2003?

SIST I-ETS 300 302-1 E1:2003 is used by terminal designers, audio engineers, and test laboratories working on ISDN videotelephony equipment. It is also relevant to certification and quality teams that need to verify handset acoustics, coding behavior, delay, sidetone, TCLw, and safety-related considerations before declaring conformance.

What changed in SIST I-ETS 300 302-1 E1:2003 from the previous edition?

SIST I-ETS 300 302-1 E1:2003 corresponds to I-ETS 300 302-1 Edition 1. The history records the original December 1994 edition.

Which standards are used with SIST I-ETS 300 302-1 E1:2003?

SIST I-ETS 300 302-1 E1:2003 relies on several related standards and recommendations for coding, service definitions, and test methods.

• CCITT Recommendation G.711 - Defines PCM voice coding, including A-law and μ-law.
• ETS 300 264 - Describes the ISDN videotelephony teleservice.
• I-ETS 300 245-2 - Gives handset telephony characteristics and related test methods for A-law.
• ETS 300 085 - Provides handset attachment and test methods used for several checks.
• ETS 300 145 - Defines videotelephony terminal modes and terminal types.
• ETS 300 144 - Defines frame structure and in-band signalling.
• ETS 300 111 - Describes the 3.1 kHz telephony teleservice.
• ETS 300 143 - Covers in-band signalling procedures.
• ETS 300 267-1 - Covers DSS1 protocol and fallback/interworking signalling.
• CCITT Recommendation G.122 - Provides the weighting used for TCLw.
• CCITT Recommendation G.101 - Defines the 0 dBr reference point.
• ITU-T Recommendations P.57, P.64, and P.79 - Support ear simulation, test positioning, and loudness calculations.
• ISO 3 and IEC 225 - Support preferred-number frequency points and octave-band measurements.
• ITU-T Recommendation P.31 - Provides transmission characteristics used for μ-law conformance checks.

SLOVENSKI STANDARD
01-december-2003
'LJLWDOQRRPUHåMH]LQWHJULUDQLPLVWRULWYDPL,6'1±'DOMLQVNHVWRULWYH
YLGHRWHOHIRQLMD±GHO(OHNWURDNXVWLþQHNDUDNWHULVWLNH]DIXQNFLMRWHOHIRQLMHV
SRJRYRUNRSULXSRUDELNRGLUDQMD]LPSXO]QRNRGQRPRGXODFLMR3&0
Integrated Services Digital Network (ISDN); Videotelephony teleservice; Part 1:
Electroacoustic characteristics for handset telephony function when using Pulse Code
Modulation (PCM) encoding
Ta slovenski standard je istoveten z: I-ETS 300 302-1 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 300 302-1
TELECOMMUNICATION December 1994
STANDARD
Source: ETSI TC-TE Reference: DI/TE-04008.1
ICS: 33.080
ISDN, videotelephony terminals, audio
Key words:
Integrated Services Digital Network (ISDN);
Videotelephony teleservice
Part 1: Electroacoustic characteristics for handset
telephony function when using Pulse Code Modulation (PCM)
encoding
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 1994. All rights reserved.
New presentation - see History box

Page 2
I-ETS 300 302-1: December 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.

Page 3
I-ETS 300 302-1: December 1994
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.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
Annex A (normative): Test methods.13
A.1 General conditions for testing.13
A.2 Delay .13
A.2.1 Sending.13
A.2.2 Receiving .13
A.3 Listener SideTone Rating (LSTR) .13
A.4 Weighted Terminal Coupling Loss (TCLw) .14
Annex B (informative): Bibliography.15
History.16

Page 4
I-ETS 300 302-1: December 1994
Blank page
Page 5
I-ETS 300 302-1: December 1994
Foreword
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 it's life extended for a further 2 years, be replaced by a new version of the I-ETS or, be
withdrawn.
This is the first Part of an I-ETS which is currently intended to comprise 6 parts.
Part 1: Electroacoustic characteristics for handset terminals when using Pulse
Code Modulation (PCM) encoding.
Part 2: Audio aspects - Pulse Code Modulation (PCM) A-Law loudspeaking and
handsfree.
Part 3: Wideband handset.
Part 4: Wideband coding and loudspeaking handsfree function.
Part 5: Application of 3,1 kHz bandwidth, 16 kbit/s speech coding algorithm.
Part 6: Application of low bitrate (below 32 kbit/s speech coding algorithm).
NOTE: Parts 3 to 6 of this I-ETS are still under study within ETSI.
Proposed announcement date
28th February 1995
Date of latest announcement of this I-ETS (doa):

Page 6
I-ETS 300 302-1: December 1994
Blank page
Page 7
I-ETS 300 302-1: December 1994
1 Scope
This Part of the I-ETS specifies the electroacoustic characteristics for 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 Pulse Code Modulation (PCM) encoding according to CCITT
Recommendation G.711 [1], A-law and μ-law.
The videotelephony teleservice in the ISDN is defined in ETS 300 264 [2].
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 [3].
The relevant test methods are described in I-ETS 300 245-2 [3] and in ETS 300 085 [4].
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.
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] ETS 300 264: "Integrated Services Digital Network (ISDN) - Videotelephony
teleservice - Service description".
[3] I-ETS 300 245-2 (1993): "Integrated Services Digital Network (ISDN) - Technical
characteristics of telephony terminals - Part 2: Pulse Code Modulation (PCM) A-
law, handset telephony".
[4] ETS 300 085 (1990): "Integrated Services Digital Network (ISDN) - 3,1 kHz
telephony teleservice - Attachment requirements for handset terminals".
[5] CCITT Recommendation G.122 (1988): "Influence of national systems on
stability - talker echo and listener echo in international connections".
[6] ETS 300 111 (1992): "Integrated Services Digital Network (ISDN) - Telephony
3,1 kHz teleservice - Service description".
[7] ETS 300 145: "Integrated Services Digital Network (ISDN) - Audiovisual
teleservices - Videtelephony systems and terminal equipment operating on one
or two 64 kbit/s channels".
[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.64 (1993): "Determination of sensitivity/frequency
characteristics of local telephone systems".
[10] CCITT Recommendation G.701 (1988): "Vocabulary of digital transmission and
multiplexing, and pulse code modulation (PCM) terms".
[11] CCITT Recommendation I.112 (1988): "Vocabulary of terms for ISDNs".

Page 8
I-ETS 300 302-1: December 1994
[12] CCITT Recommendation P.10 (1988): "Vocabulary of terms on telephone
transmission quality and telephone sets".
[13] ETS 300 143 (1993): "Integrated Services Digital Network (ISDN) - Audiovisual
services inband signalling procedures for audiovisual terminals using digital
channels up to 2 048 kbit/s".
[14] CCITT Recommendation G.725 (1988): "System aspects for the use of the 7
kHz audio codec within 64 kbit/s".
[15] 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".
[16] ITU-T Recommendation P.31 (1993): "Transmission characteristics for digital
telephones".
[17] CCITT Recommendation G.101 (1988): "The transmission plan".
[18] ISO 3 (1977): "Preferred numbers - Series of preferred numbers".
[19] ITU-T Recommendation P.57 (1993): "Artificial ears".
[20] IEC 225: "Octave, half-octave and third-octave band filters intended for the
analysis of sound and vibrations".
[21] ITU-T Recommendation P.79 (1993): "Calculation of loudness ratings for
telephone sets".
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
[9].
modes of operation: For the videotelephony teleservice in the ISDN, the modes of operation are defined
in ETS 300 145 [7].
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 octet. The structure of a 64 kbit/s channel (B-channel)
and the position of the service channel is described in ETS 300 144 [8].
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 [6].
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.
...