SIST I-ETS 300 245-2 E1:2003

• Abstract:

  Specify telephony terminal used at S/T interface of basic access to the ISDN, including electrical, logical and acoustical characteristics

• 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 300 245-2 ed.1 (1994-05) - Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals; Part 2: PCM A-law handset telephony

SIST I-ETS 300 245-2 E1:2003 is the Slovenian standard for ETSI's Interim European Telecommunication Standard on ISDN telephony terminals, Part 2: PCM A-law handset telephony. It specifies technical characteristics for handset telephony terminals used at the basic access of the Integrated Services Digital Network (ISDN), including electrical, logical and acoustical behaviour.

This document is aimed at terminal designers, manufacturers, test laboratories and purchasers who need to check whether a handset terminal fits the ISDN basic access and meets the additional performance characteristics described here.

What does SIST I-ETS 300 245-2 E1:2003 specify?

SIST I-ETS 300 245-2 E1:2003 specifies the technical characteristics for Pulse Code Modulation (PCM) A-law 3,1 kHz handset telephony terminals at the coincident S and T reference point of ISDN basic access. The characteristics in this part are additional to those in Part 1 and are supplementary to the mandatory requirements in ETS 300 085.

The standard is organized into scope, normative references, definitions and abbreviations, call control functions, transmission aspects, power feeding, and physical modules. It is supported by three annexes: one normative annex for test specifications and two informative annexes for acoustic shock guidance and bibliography.

Annex	What it covers
Annex A	Normative test specifications for sidetone, weighted terminal coupling loss and delay
Annex B	Informative acoustic shock requirements and guidance for supplier declaration
Annex C	Informative bibliography

What are the key requirements of SIST I-ETS 300 245-2 E1:2003?

SIST I-ETS 300 245-2 E1:2003 sets the main requirements in Clause 4, Clause 5, Clause 6 and Clause 7, with supporting test methods in Annex A. In practice, it tells a supplier what the terminal has to do, how key speech characteristics are checked, and which parts rely on the general ISDN handset standard.

Call control and basic conformance

Clause 4 requires the terminal to meet the call control functions in I-ETS 300 245-1. For a buyer or test house, this means Part 2 is not a standalone specification - it builds on the general requirements of Part 1.

Speech coding and interface level

Clause 5.1.1 sets A-law encoding at 64 kbit/s as the default speech coding algorithm. Clause 5.1.2 defines the digital interface as the 0 dBr point, and Clause 5.1.3 says the requirements apply across all positions of any user-controlled receiving volume control unless stated otherwise. This matters because all loudness and speech measurements are referenced to a common transmission point.

Frequency response and sensitivity

Clause 5.2.1 requires sending and receiving frequency response and sensitivity to be measured as described in ETS 300 085. The sending path is checked from the Mouth Reference Point (MRP) to the digital interface, and the receiving path from the digital interface to the Ear Reference Point (ERP). The figures in this clause define the response shape expected for good naturalness and intelligibility, so the terminal is not just loud enough - it must also pass speech in a balanced way.

Sidetone

Clause 5.2.3 sets limits for both talker sidetone and listener sidetone. The SideTone Masking Rating (STMR) has to fall within a stated range, and the Listener SideTone Rating (LSTR) must not be below its minimum value after correction to nominal sending and receiving loudness ratings. In practice, this controls how much of the user's own speech comes back into the ear and helps prevent a "too closed" or overly echoic handset experience.

Terminal coupling loss and stability

Clause 5.2.4 sets requirements for Weighted Terminal Coupling Loss (TCLw), including a minimum value at nominal loudness ratings and a lower minimum at all volume settings. The clause also points to ETS 300 085 for stability loss, with a changed measurement input level. These requirements are important for echo control, especially when the handset is used in networks where sidetone and loop stability affect speech quality.

Distortion, gain variation and non-linear devices

Clause 5.2.5 refers distortion measurements to ETS 300 085. Clause 5.2.6 allows equivalent evaluation methods when switch-gain amplifiers, automatic volume control or compressor/expander techniques are used, provided the method is documented by the supplier and accepted by the test house for a certificate of conformance. This is relevant for modern speech-processing terminals because the standard allows non-linear techniques, but asks for equivalent proof rather than a single fixed method.

Out-of-band signals, acoustic shock and delay

Clause 5.2.7 limits spurious out-of-band image signals at the receiving side using a simulated digital sine-wave signal and selective acoustic measurement in an artificial ear. Clause 5.2.9 treats acoustic shock as a safety matter linked to the Low Voltage Directive and points to Annex B for guidance. Clause 5.2.10 limits total delay from MRP to the digital interface plus digital interface to ERP to 2,0 ms. For users, these provisions affect how natural the speech sounds, how safe the receiver is, and how much delay is added to a conversation.

What terms does SIST I-ETS 300 245-2 E1:2003 define?

SIST I-ETS 300 245-2 E1:2003 relies on several defined terms that matter for measurement and interpretation.

• Terminal Coupling Loss (TCL) - The frequency-dependent loss between the receiving port and sending port of a terminal, including acoustic, electrical and seismic coupling effects.
• Weighted Terminal Coupling Loss (TCLw) - TCL weighted according to CCITT Recommendation G.122, used to judge echo-related performance.
• SideTone Masking Rating (STMR) - A measure of talker sidetone masking, used to show how much of the user's own voice returns to the ear.
• Listener SideTone Rating (LSTR) - A sidetone measure for the listener side, used to assess the acoustic feedback path in the receiving direction.
• Mouth Reference Point (MRP) - The reference point used for acoustic input at the user's mouth side.
• Ear Reference Point (ERP) - The reference point used for acoustic output at the user's ear side.
• Sending Loudness Rating (SLR) - The loudness rating used for the sending path from mouth to digital interface.
• Receiving Loudness Rating (RLR) - The loudness rating used for the receiving path from digital interface to ear.

Who uses SIST I-ETS 300 245-2 E1:2003?

SIST I-ETS 300 245-2 E1:2003 is used by terminal manufacturers, acoustic and transmission test laboratories, certification and type-approval teams, and quality managers who need to verify handset performance on ISDN basic access. It is also useful to buyers and technical evaluators who compare handset terminals for speech quality, echo behaviour, delay and safety-related acoustic shock guidance.

The document is especially relevant when a supplier has to document equivalent evaluation methods for non-linear speech-processing designs, or when a test house has to check sidetone, coupling loss, delay or out-of-band signal behaviour.

Which standards are used with SIST I-ETS 300 245-2 E1:2003?

SIST I-ETS 300 245-2 E1:2003 is used together with the following named standards and recommendations:

• I-ETS 300 245-1 - the general part that supplies the base requirements for ISDN telephony terminals.
• ETS 300 085 - the main companion standard for attachment requirements, loudness ratings, frequency response, distortion and several test methods.
• ETS 300 111 - gives the 3,1 kHz telephony teleservice description referred to in the definitions.
• CCITT Recommendation P.10 and G.701 - provide the core vocabulary and terms used in the document.
• CCITT Recommendation G.122 - provides the weighting used for TCLw.
• CCITT Recommendation G.711 - defines the PCM A-law coding used as the default speech encoding.
• CCITT Recommendation G.101 - defines the transmission plan reference for the 0 dBr point.
• ITU-T Recommendation P.79, IEC 225 and ISO 3 - support the loudness calculations, band measurements and preferred-number frequency points used in testing.
• CCITT Recommendation P.64 - supports the pink-noise method used in listener sidetone testing.
• CCITT Recommendation P.35, P.57, G.714 and ISO 9614 - appear in the bibliography as related guidance on handset design, artificial ears, PCM channel performance and sound intensity.

What does the SIST I-ETS 300 245-2 E1:2003 document contain?

SIST I-ETS 300 245-2 E1:2003 contains the technical structure for defining handset telephony performance on ISDN basic access, with figures for sending and receiving frequency response, a table for out-of-band signal limits, and test procedures for sidetone, coupling loss and delay. It also gives measurement setups using an artificial ear, artificial mouth and reference points such as MRP and ERP.

Annex A provides the practical test arrangements and calculation methods used for conformance checking. Annex B gives advisory acoustic shock limits for supplier self-declaration, based on artificial-ear measurements. The body of the document also describes how user-controlled volume control, non-linear speech techniques and power feeding are to be treated within the overall terminal specification.

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Integrated Services Digital Network (ISDN); Technical characteristics of telephony
terminals; Part 2: PCM A-law handset telephony
Ta slovenski standard je istoveten z: I-ETS 300 245-2 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.

EUROPEAN I-ETS 300 245-2
TELECOMMUNICATION May 1994
STANDARD
Source: ETSI TC-TE Reference: T/TE 10-07 (B)
ICS: 33.020, 33.040.40
ISDN, telephony terminals, handset function
Key words:
Integrated Services Digital Network (ISDN);
Technical characteristics of telephony terminals
Part 2: PCM A-Law handset telephony
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

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I-ETS 245-2: May 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 245-2: May 1994
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .8
4 Call control functions.9
5 Transmission aspects .9
5.1 General .9
5.1.1 Encoding .9
5.1.2 Relative level .9
5.1.3 Volume control .9
5.2 Speech performance characteristics .9
5.2.1 Frequency response and sensitivity .9
5.2.1.1 Sending.9
5.2.1.2 Receiving.10
5.2.2 Volume control .11
5.2.3 Sidetone .11
5.2.3.1 Talkers sidetone .11
5.2.3.2 Listeners sidetone.12
5.2.4 Terminal Coupling Loss (TCL) .12
5.2.4.2 Weighted Terminal Coupling Loss (TCLw).12
5.2.4.2 Stability loss.12
5.2.5 Distortion .12
5.2.5.1 Sending.12
5.2.5.2 Receiving.12
5.2.5.3 Sidetone.12
5.2.6 Variation of gain with input level.13
5.2.6.1 Sending.13
5.2.6.2 Receiving.13
5.2.7 Out-of-band signals.13
5.2.7.1 Discrimination against out-of-band input signals (Sending) 13
5.2.7.2 Spurious out-of-band signals (Receiving).13
5.2.8 Noise .13
5.2.8.1 Sending.13
5.2.8.2 Receiving.14
5.2.8.3 Level of sampling frequency (Receiving).14
5.2.9 Acoustic shock .14
5.2.10 Delay .14
5.3 Non-linear devices .14
6 Power feeding .14
6.1 General conditions.14
7 Physical modules .14
7.1 Handset.14
7.2 Audible alerting module .14

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I-ETS 245-2: May 1994
Annex A (normative): Test specifications . 15
A.1 General conditions for testing. 15
A.2 Sidetone. 15
A.2.1 Talker sidetone. 15
A.2.2 Listener sidetone. 15
A.3 Weighted terminal coupling loss. 16
A.4 Delay. 16
Annex B (informative): Acoustic shock requirements. 18
B.1 Continuous signal . 18
B.2 Peak signal . 18
Annex C (informative): Bibliography . 18
History. 19

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I-ETS 245-2: May 1994
Foreword
This Interim European Telecommunication Standard (I-ETS) was prepared by the Terminal Equipment
(TE) Technical Committee of the European Telecommunications Standards Institute (ETSI).
An ETSI 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 an 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 second part of an I-ETS which is currently intended to comprise eight parts.
This I-ETS specifies technical characteristics for Integrated Services Digital Network (ISDN) telephony
terminals as described in the scope of this I-ETS. The characteristics are additional to type approval
requirements to which the terminal equipment is subject. The additional characteristics are meant to give
improved performance.
In the present version of this I-ETS the following parts are included:
Part 1: General (I-ETS 300 245-1 [1]).
Part 2: PCM A-law, handset telephony.
Part 3: PCM A-law, loudspeaking and handsfree telephony.
Part 4: Interface for additional equipment.
Part 5: Wideband (7 kHz) handset telephony.
Part 6: Wideband (7 kHz) handsfree telephony.
Part 7: Locally generated information tones.
Part 8: Terminal application of 16 kbit/s speech coding algorithms.
NOTE: Part 8 is still under study within ETSI.

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I-ETS 245-2: May 1994
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I-ETS 245-2: May 1994
1 Scope
This Part of this Interim European Telecommunication Standard (I-ETS) specifies the technical
characteristics for Pulse Code Modulation (PCM) A-law 3,1 kHz handset telephony terminals to be used at
the basic access for the coincident S and T reference point of the Integrated Services Digital Network
(ISDN).
This Part applies in conjunction with I-ETS 300 245-1 [1] and the characteristics specified in this Part are
additional to those of I-ETS 300 245-1 [1].
The present version of this part does not cover measurements on receivers (in handsets) with low acoustic
output impedance.
NOTE: The characteristics specified in this I-ETS are supplementary to the mandatory
requirements given in ETS 300 085 [2].
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] I-ETS 300 245-1 (1994): "Integrated Services Digital Network (ISDN); Technical
characteristics of telephony terminals, Part 1 - General".
[2] ETS 300 085 (1990): "Integrated Services Digital Network (ISDN); 3,1 kHz
telephony teleservice, Attachment requirements for handset terminals".
[3] CCITT Recommendation P.10 (1988): "Vocabulary of terms on telephone
transmission quality and telephone sets".
[4] CCITT Recommendation G.701 (1988): "Vocabulary of digital transmission and
multiplexing, and pulse code modulation (PCM) terms".
[5] ETS 300 111 (1992): "Integrated Services Digital Network (ISDN); Telephony
3,1 kHz teleservice, Service description".
[6] CCITT Recommendation G.122 (1988): "Influence of national systems on
stability, talker echo and listener echo in international connections".
[7] CCITT Recommendation G.711 (1988): "Pulse code modulation (PCM) of voice
frequencies".
[8] CCITT Recommendation G.101 (1988): "The transmission plan".
[9] ITU-T Recommendation P.79 (1993): "Calculation of loudness ratings".
[10] IEC 225: "Octave, half-octave and third-octave band filters intended for the
analysis of sound and vibrations".
[11] CCITT Recommendation P.64 (1988): "Determination of sensitivity/frequency
characteristics of local telephone systems to permit calculation of their loudness
ratings".
[12] ISO 3 (1973): "Preferred numbers - Series of preferred numbers".

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I-ETS 245-2: May 1994
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this I-ETS, the relevant definitions given in CCITT Recommendations P.10 [3] and G.701
[4] apply along with the following.
Telephony 3,1 kHz teleservice: A description of the telephony 3,1 kHz teleservice is to be found in ETS 300
111 [5].
Loudspeaking telephony terminal: A handset telephony terminal using a loudspeaker associated with
an amplifier as a telephone receiver. Defined in CCITT Recommendation P.10 [3].
Handsfree telephony terminal: A telephony terminal using a loudspeaker associated with an amplifier as
a telephone receiver and which can be used without a handset. Defined in CCITT Recommendation P.10
[3].
Terminal Coupling Loss (TCL): The frequency dependent coupling loss between the receiving port and
sending port of a terminal due to:
- acoustic 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 will depend on the conditions of use.
Weighted Terminal Coupling Loss (TCLw): The weighted TCL using the weighting of CCITT
Recommendation G.122 [6].
Digital interface: For the purposes of this I-ETS, the digital interface refers to the B-channels available at
the coincident S and T reference point at an ISDN basic access.
3.2 Abbreviations
For the purposes of this I-ETS, the relevant abbreviations in CCITT Recommendations P.10 [3] and G.701
[4] apply.
ERP Ear Reference Point, see CCITT Recommendation P.10 [3]
ETS European Telecommunication Standard
ETSI European Telecommunications Standards Institute
I-ETS Interim European Telecommunication Standard
ISDN Integrated Services Digital Network
LRGP Loudness Rating Guard-ring Position
LSTR Listener Side Tone Rating
MRP Mouth Reference Point, see CCITT Recommendation P.10 [3]
PCM Pulse Code Modulation
RLR Receiving Loudness Rating
SLR Sending Loudness Rating
STMR Side Tone Masking Rating
TCL Terminal Coupling Loss
TCLw weighted Terminal Coupling Loss

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I-ETS 245-2: May 1994
4 Call control functions
The requirements of I-ETS 300 245-1 [1] shall be met.
5 Transmission aspects
5.1 General
Recommendations and requirements for PCM A-law terminals are given here and in ETS 300 085 [2]. When
using other coding algorithms other parts of this I-ETS may apply.
5.1.1 Encoding
The default speech encoding algorithm for all telephony terminals shall be the A-law encoding at 64 kbit/s as
defined in CCITT Recommendation G.711 [7]. Any other possible encoding algorithm will be additional. For
some encoding algorithms recommendations are given in other parts of this I-ETS.
5.1.2 Relative level
The digital interface is defined as a 0 dBr point according to CCITT Recommendation G.101 [8].
5.1.3 Volume control
Unless stated otherwise, the requirements apply for all positions of the user-controlled receiving volume
control, if provided.
5.2 Speech performance characteristics
5.2.1 Frequency response and sensitivity
The frequency responses and sensitivities shall be measured as described in ETS 300 085 [2].
5.2.1.1 Sending
Requirements for the sending sensitivity (Sending Loudness Rating (SLR)) are given in ETS 300 085 [2].
The frequency response (from Mouth Reference Point (MRP) to digital interface) shall be within the limits
restricted by the fully drawn lines in figure 1.
In figure
...