kSIST prES 203 038 V1.2.1:2013

• Abstract:

  RES/STQ-203038

• Status: Not Published
• ICS: 33.040.35 - Telephone networks
• ICS: 33.050.01 - Telecommunication terminal equipment in general
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 13-Mar-2013
• Due Date: 01-May-2013
• Completion Date: 16-Jul-2013
• Ref Project: ETSI ES 203 038 V1.2.1 (2013-05) - Speech and multimedia Transmission Quality (STQ); Requirements and tests methods for terminal equipment incorporating a handset when connected to the analogue interface of the PSTN

kSIST prES 203 038 V1.2.1:2013 presents ETSI ES 203 038 V1.2.1 (2013-05), an ETSI standard for handset telephony terminal equipment. It specifies electrical and acoustic requirements, plus test methods, for single handset equipment connected by two wires to the analogue interface of the PSTN. The document is meant for manufacturers, test labs, and compliance teams that need to verify speech quality and transmission performance.

What does kSIST prES 203 038 V1.2.1:2013 specify?

kSIST prES 203 038 V1.2.1:2013 specifies the technical characteristics, test conditions, and measurement methods for handset telephony over the analogue interface of the Public Switched Telephone Network (PSTN). It focuses on two-way real-time speech through a handset, including analogue handset terminals intended for gateways and handset telephony used over radio links such as DECT.

The scope also sets clear boundaries. The document applies to handset telephony function only, and if a terminal has other functions, the standard applies only when those other functions are not active together with handset telephony. It is not intended for accessibility-oriented amplified speech, hostile-environment speech performance, handsfree or loudspeaking telephony, or speech processing techniques other than coding.

The document is organized into:

• Clause 1: Scope
• Clause 2: References
• Clause 3: Definitions, symbols and abbreviations
• Clause 4: Speech transmission aspects
• Annex A: Requirements for LRGP measured terminals
• Annex B: Speech transmission compliance tests for LRGP measured terminals
• Annex C: Table of changes relative to TBR 038
• Annex D: Overview on levels constraints for measurements
• Annex E: Bibliography

Annex	What it covers
Annex A	Normative requirements for terminals designed for LRGP-based measurement
Annex B	Normative compliance tests for LRGP-based measurement
Annex C	Changes relative to TBR 038
Annex D	Level constraints used in measurements
Annex E	Bibliography

What are the key requirements of kSIST prES 203 038 V1.2.1:2013?

kSIST prES 203 038 V1.2.1:2013 sets out a HATS-based test regime in Clause 4, with legacy LRGP requirements and tests retained in Annexes A and B. In practice, a supplier needs to know which measurement setup the terminal is designed for, because the reference position, correction method, and some limit values differ.

General test conditions

Clause 4.1 requires the terminal to meet the document for both line polarities, so the results must not depend on which way the line feeding voltage is connected. Clause 4.1.2 requires testing at 50 V with feed resistances from 500 Ω to 2 800 Ω, which reflects different line conditions a terminal may see in service.

Clause 4.1.4 sets the nominal user-controlled receiving volume setting at the point where the Receiving Loudness Rating (RLR) is as close as possible to -8 dB. That matters because the rest of the speech tests are performed at a defined, repeatable listening setting.

Clause 4.1.5 and 4.1.11 define the HATS setup for the main part of the standard. The handset is placed on a Head And Torso Simulator (HATS), with diffuse-field correction for most measurements and Drum Reference Point (DRP) to Ear Reference Point (ERP) correction for RLR. In practice, the lab must use the right artificial ear, mounting force, and calibration method before comparing results to the limits.

Core speech-performance limits

Clause 4.2.1 sets frequency-response limits for sending and receiving sensitivity. The measurements run from 100 Hz to 8 kHz in one-twelfth-octave steps, which helps catch peaks, dips, and unwanted filtering across the speech band.

Clause 4.2.2 sets target loudness ratings. The Sending Loudness Rating (SLR) is centered on +3 dB, and the RLR is centered on -8 dB, with checks at several feed resistances. This tells a buyer or designer whether the handset will sound too quiet, too loud, or unbalanced across different line conditions.

Clause 4.2.3 limits sidetone by requiring SideTone Masking Rating (STMR) of at least +10 dB in the main HATS-based tests. That matters because sidetone controls how much of the user’s own voice is heard in the receiver, which affects comfort and natural conversation.

Clause 4.2.4 limits harmonic distortion, with tighter limits in the main clause than in the LRGP annexes. Clause 4.2.5 limits gain variation with input level to within ±2 dB, so the handset should not change character too much between quiet and louder speech.

Clause 4.2.6 sets noise limits in both directions, using psophometric weighting for sending noise and A-weighting for receiving noise. This is the part that helps control background hiss and idle-channel noise that users notice immediately.

Safety and network-interaction checks

Clause 4.2.7 adds acoustic shock limits. The receiving path must limit both continuous and peak sound pressure at the Ear Reference Point, which matters for user safety and for protecting against unexpected high-level audio events.

Clause 4.2.8 addresses instability. The handset must not produce sustained audible oscillation under the stated corner-position test and maximum receiving gain setting. Clause 4.2.9 sets a minimum Echo Return Loss (ERL) of 14 dB, so the terminal should not reflect too much speech energy back into the network.

Legacy LRGP requirements and tests

Annex A repeats the requirement set for terminals designed around LRGP measurement instead of HATS. Annex B gives the matching compliance tests. For these terminals, the same main topics apply - sensitivity, loudness ratings, sidetone, distortion, linearity, noise, instability, and ERL - but the setup and some limits are different, so the lab must follow the annex that matches the terminal design.

What terms does kSIST prES 203 038 V1.2.1:2013 define?

• Head And Torso Simulator (HATS) - a manikin used to simulate human sound pick-up and mouth radiation in telephony measurements.
• Loudness Rating Guard-ring Position (LRGP) - the handset placement used in the legacy measurement method retained in Annexes A and B.
• Sending Loudness Rating (SLR) - a dB measure of how loud the sending path is, used to judge transmit speech level.
• Receiving Loudness Rating (RLR) - a dB measure of how loud the receiving path is, used to judge listen volume.
• SideTone Masking Rating (STMR) - a measure of how much the handset masks the user’s own voice in the receiver.
• Echo Return Loss (ERL) - a return-loss measure averaged over the telephone band, used to assess reflected speech energy.
• Mouth Reference Point (MRP) - the reference point in front of the mouth where acoustic test signals are set.
• Public Switched Telephone Network (PSTN) - the public switched telephone network to which the handset terminal connects.

Who uses kSIST prES 203 038 V1.2.1:2013?

kSIST prES 203 038 V1.2.1:2013 is used by handset terminal manufacturers, gateway suppliers, and test laboratories that need to design or verify analogue PSTN speech performance. Quality teams and compliance engineers use it to confirm that a terminal meets the expected transmission and acoustic behavior before release.

It is also relevant to buyers and integrators who need to compare handset telephony products on a common technical basis. Because the scope includes analogue handset terminals intended for gateways and radio-linked handset applications such as DECT, it is useful across fixed telephony, telecom equipment development, and conformance testing.

What changed in kSIST prES 203 038 V1.2.1:2013 from the previous edition?

Annex C states that this standard updates TBR 038 and moves the main measurement approach from LRGP to HATS. It also records new definitions, symbols, abbreviations, references, and a revised scope that includes compatibility with radio-linked handsets.

The changes called out in Annex C include updated sensitivity limits, revised loudness rating treatment, changed distortion limits, changed noise test methods, and the addition of acoustic shock requirements. Annex C also shows that Annexes A and B preserve the earlier LRGP-based requirements and tests for terminals designed around that method.

Which standards are used with kSIST prES 203 038 V1.2.1:2013?

The normative references provide the measurement tools and calculation methods behind the standard:

• ITU-T G.122 - defines the basis for ERL and talker-echo related calculations.
• ITU-T P.64 - gives the sensitivity/frequency measurement methods for local telephone systems.
• ITU-T P.51 - defines the artificial mouth.
• ITU-T P.57 - defines the artificial ear and ear-reference corrections.
• IEC 651 - specifies the sound level meter type used for measurement.
• ISO 3 - provides the preferred-number series used for test frequencies.
• ITU-T P.79 - defines the loudness rating calculation methods.
• ITU-T O.41 - defines psophometric weighting for telephone-type circuits.
• ITU-T P.50 and ITU-T P.501 - provide speech-like activation signals and CSS when needed.
• ITU-T P.58 - defines the HATS setup and diffuse-field correction.
• ETSI TBR 38 - is the predecessor document whose content is updated here.

Informative references add context for handset telephones, objective loudness tools, and related STQ documents, including ETSI ES 202 738 and ETSI EG 202 518.

What does the kSIST prES 203 038 V1.2.1:2013 document contain?

The document contains the test circuits, measurement setups, correction methods, and acceptance-limit figures used for handset telephony conformance. It includes frequency-response plots, insertion-loss and return-loss arrangements for the feeding circuit, and formulas for loudness ratings, distortion, RL, and ERL.

It also contains separate annexed procedures for LRGP-measured terminals, so users can apply the standard either with the newer HATS-based approach or with the legacy LRGP-based approach. Annex D gives a practical overview of level constraints, which helps test engineers set up measurements consistently.

Final draft ETSI ES 203 038 V1.2.1 (2013-03)

ETSI Standard
Speech and multimedia Transmission Quality (STQ);
Requirements and tests methods for terminal
equipment incorporating a handset when connected to the
analogue interface of the PSTN

2 Final draft ETSI ES 203 038 V1.2.1 (2013-03)

Reference
RES/STQ-203038
Keywords
analogue, PSTN, telephony, terminal
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3 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
Contents
Intellectual Property Rights . 6
Foreword . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 8
2.2 Informative references . 8
3 Definitions, symbols and abbreviations . 9
3.1 Definitions . 9
3.2 Symbols . 9
3.3 Abbreviations . 10
4 Speech transmission aspects . 10
4.1 General . 10
4.1.1 Polarity independence . 10
4.1.2 Feed conditions . 10
4.1.3 Power supply . 10
4.1.4 Volume control . 11
4.1.5 Test setup . 11
4.1.6 Environment for tests . 11
4.1.7 Accuracy of measurements and test equipment setting . 12
4.1.8 Order of tests. 12
4.1.9 Acoustic environment . 12
4.1.10 Alternative test methods . 12
4.1.11 Testing arrangements . 13
4.2 Speech performance characteristics. 16
4.2.1 Sensitivity/frequency response . 16
4.2.1.1 Sending Sensitivity . 16
4.2.1.2 Receiving Sensitivity . 17
4.2.2 Sending and Receiving Loudness Ratings (SLR and RLR) . 19
4.2.2.1 Sending Loudness Rating (SLR) . 19
4.2.2.2 Receiving Loudness Rating (RLR) . 19
4.2.3 Sidetone . 20
4.2.4 Distortion . 21
4.2.4.1 Sending distortion . 21
4.2.4.2 Receiving distortion . 22
4.2.5 Linearity (variation of gain with input level) . 23
4.2.5.1 Sending linearity . 23
4.2.5.2 Receiving linearity . 23
4.2.6 Noise . 23
4.2.6.1 Sending noise . 23
4.2.6.2 Receiving noise . 24
4.2.7 Acoustic shock . 24
4.2.7.1 Continuous signal . 24
4.2.7.2 Peak signal . 24
4.2.8 Instability . 25
4.2.9 Echo Return Loss (ERL) . 26
Annex A (normative): Requirements for LRGP measured terminals . 28
A.1 Speech transmission aspects . 28
A.1.1 General . 28
A.1.1.1 Polarity independence . 28
A.1.1.2 Feed conditions . 28
A.1.1.3 Power supply . 28
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4 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
A.1.1.4 Volume control . 28
A.2 Speech performance characteristics . 29
A.2.1 Sensitivity/frequency response . 29
A.2.1.1 Sending Sensitivity . 29
A.2.1.2 Receiving Sensitivity . 29
A.2.2 Sending and Receiving Loudness Ratings (SLR and RLR) . 30
A.2.2.1 Sending Loudness Rating (SLR) . 30
A.2.2.2 Receiving Loudness Rating (RLR) . 31
A.2.3 Sidetone . 31
A.2.4 Distortion . 31
A.2.4.1 Sending distortion . 31
A.2.4.2 Receiving distortion . 31
A.2.5 Linearity (variation of gain with input level) . 32
A.2.5.1 Sending linearity . 32
A.2.5.2 Receiving linearity . 32
A.2.6 Noise . 32
A.2.6.1 Sending noise . 32
A.2.6.2 Receiving noise . 32
A.2.7 Instability . 33
A.2.8 Echo Return Loss (ERL) . 33
Annex B (normative): Speech transmission compliance tests for LRGP measured terminals . 34
B.1 General conditions for testing . 34
B.1.1 Environment for tests . 34
B.1.2 Accuracy of measurements and test equipment setting . 34
B.1.3 Order of tests . 35
B.1.4 Acoustic environment . 35
B.1.5 Handset mounting. 35
B.1.6 Test levels . 35
B.1.6.1 Sending . 35
B.1.6.2 Receiving . 35
B.1.6.3 Sidetone . 35
B.1.7 Volume control . 35
B.1.8 Test equipment requirements . 36
B.1.9 Alternative test methods . 36
B.1.10 Testing arrangements . 36
B.2 Speech transmission performance tests for LRGP measured terminals . 39
B.2.1 Sensitivity/frequency response . 39
B.2.1.1 Sending sensitivity . 39
B.2.1.2 Receiving sensitivity . 39
B.2.2 Loudness ratings . 40
B.2.2.1 Sending loudness rating . 40
B.2.2.2 Receiving loudness rating . 40
B.2.3 Sidetone . 41
B.2.4 Distortion . 42
B.2.4.1 Sending distortion . 42
B.2.4.2 Receiving distortion . 43
B.2.5 Linearity (variation of gain with input level) . 43
B.2.5.1 Sending linearity . 43
B.2.5.2 Receiving linearity . 44
B.2.6 Noise . 44
B.2.6.1 Sending noise . 44
B.2.6.2 Receiving noise . 44
B.2.7 Instability . 45
B.2.8 Echo Return Loss (ERL) . 46
Annex C (informative): Table of changes relative to TBR 038 . 48
Annex D (informative): Overview on levels constraints for measurements . 51
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5 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
Annex E (informative): Bibliography . 53
History . 54

ETSI
6 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This final draft ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia
Transmission Quality (STQ), and is now submitted for the ETSI standards Membership Approval Procedure.
The present document has been produced by ETSI in order to update the contents of initial standards for PSTN
(e.g. TBR 038 [14]).
In particular, the update aims to take benefits of recent improvements in test methods and test equipments. Even the
purpose of the standard is to consider Narrowband speech characteristics and test methods, the new test methods leave
the door open for further services (e.g. wideband speech).
In this release 1 of the present document, no new measurement will be added except limitation of acoustic shock which
is a requirement for safety. Previous requirements and test methods are kept in an annex in order to be used for
terminals designed with LRGP method. Status of this annex is planned to be informative, but only in release 2.
The new measurements needed for handset terminal including speech processing functions will be introduced in a
further release taking into account this type of terminal.
Introduction
The present document specifies only the technical characteristics for handset telephony and is intended to be used in
conjunction with an appropriate access standard.
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7 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
1 Scope
The present document specifies the technical characteristics (electrical and acoustic requirements and measurement
methods) to be provided by a single, handset telephony, terminal equipment which is intended for connection by 2 wires
to an analogue interface of a PSTN. This interface is characterized by a d.c. loop to indicate seizure and clearing, low
frequency a.c. ringing signals below the speech passband to indicate an incoming call and the transmission phase having
an approximate bandwidth of 3 kHz at the network terminating point.
The objective of the present document is to ensure minimum speech quality when interworking via the public network
between two single items of equipment.
The present document only applies to terminal equipment supporting handset telephony.
The present document is applicable to handset telephony function. In the case of multiple functions provided in the
same terminal equipment, the present document does not apply when those other functions are active in conjunction
with handset telephony.
The present document also applies to any type of analogue handset terminal intended to be connected to a gateway.
The present document specifies the functions necessary to provide 2-way real-time speech conversation. Where a
function is indicated as optional, it needs not to be provided, but, where such a function is provided, the terminal needs
to conform to the requirements and tests specified in the present document.
A test is given for each requirement in the present document including measurement methods. The terminal equipment
may be stimulated to perform the tests by additional equipment if necessary.
The present document gives requirements for new test methods based upon use of HATS and new tests signals.
In an annex, requirements with test methods corresponding to previous tests methods (LRGP) and test signals are given.
The application of the present document is intended also for handset telephony function employing a radio link
(e.g. DECT).
The application of the present document is not intended for:
• a handset telephony function with speech transmission performance specially designed for the less abled (e.g.
with amplification of received speech as an aid for the hard of hearing);
• a handset telephony function with speech transmission performance specifically designed to cater for hostile
environments;
• any handsfree or loudspeaking voice telephony function;
• a handset telephony function employing speech processing techniques other than coding.
NOTE: The terminal equipment may provide additional functions or facilities to those of handset telephony.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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8 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T G.122 (03/93): "Influence of national systems on stability and talker echo
in international connections".
[2] Recommendation ITU-T P.64 (11/07): "Determination of sensitivity/frequency characteristics of
local telephone systems".
[3] Recommendation ITU-T P.51 (08/96): "Artificial mouth".
[4] Recommendation ITU-T P.57 (11/05): "Artificial ears".
[5] IEC 651: "Sound level meters".
[6] ISO 3 (1973): "Preferred numbers - Series of preferred numbers".
[7] Recommendation ITU-T P.79 (11/07): "Calculation of loudness ratings for telephone sets".
[8] Recommendation ITU-T O.41 (10/94): "Psophometer for use on telephone-type circuits".
[9] Void.
[10] Recommendation ITU-T P.50 (09/99): "Artificial voices".
[11] Void.
[12] Recommendation ITU-T P 58 (08/96): "Head and torso simulator for telephony".
[13] Recommendation ITU-T P.501 (09/01): "Test signals for use in telephonometry".
[14] ETSI TBR 38 (05/98): "Public Switched Telephone Network (PSTN); Attachment requirements
for a terminal equipment incorporating an analogue handset function capable of supporting the
justified case service when connected to the analogue interface of the PSTN in Europe".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Void.
[i.2] ITU-T Recommendation P.35 (1988, Blue Book): "Handset telephones".
[i.3] Recommendation ITU-T P.65 (03/93): "Objective instrumentation for the determination of
loudness ratings".
[i.4] ETSI ES 202 738: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective
as perceived by the user".
[i.5] ETSI EG 202 518: "Speech and multimedia Transmission Quality (STQ); Acoustic Output of
Terminal Equipment; Maximum Levels and Test Methodology for Various Applications".
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9 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
artificial ear: device for the calibration of earphones incorporating an acoustic coupler and a calibrated microphone for
the measurement of sound pressure and having an overall acoustic impedance similar to that of the average human ear
over a given frequency band
diffuse field equalization: equalization of the HATS sound pick-up, equalization of the difference, in dB, between the
spectrum level of the acoustic pressure at the ear Drum Reference Point (DRP) and the spectrum level of the acoustic
pressure at the HATS Reference Point (HRP) in a diffuse sound field with the HATS absent (application of reverse
nominal curve of table 3 in Recommendation ITU-T P.58 [12])
Echo Return Loss (ERL): return loss averaged with 1/f power weighting over the telephone band
(300 Hz to 3 400 Hz), in accordance with clause 4 of Recommendation ITU-T G.122 [1]
handset: combination of telephone microphone and receiver in a form convenient for holding simultaneously to mouth
and ear, which, when in use, retains the microphone in a position fixed in relation to the receiver
handset telephony: function provided by terminal equipment whereby two-way real-time speech is supported by
means of a handset that forms an integral part of the terminal equipment
NOTE: The term "live speech" is also frequently used to describe "real-time speech". For the purposes of the
present document, they should be considered as having the same meaning.
handsfree function: function whereby telephony transmission and reception is facilitated by the use of microphone(s)
and loudspeaker(s) placed at a distance from the user
NOTE: No handset is required to be used and normally the handset is not active.
Head And Torso Simulator (HATS) for telephonometry: manikin extending downward from the top of the head to
the waist, designed to simulate the sound pick-up characteristics and the acoustic diffraction produced by a median
human adult and to reproduce the acoustic field generated by the human mouth
loop state: state in which the TE draws sufficient DC current to activate the exchange
loop steady state: loop state excluding the transitions from and to quiescent state
loudness rating: measure, expressed in decibels, for characterizing the loudness performance of complete telephone
connections or of parts thereof such as sending system, line, receiving system
loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a
telephone receiver
Mouth Reference Point (MRP): point 25 mm in front of and on the axis of the lip position of a typical human mouth
(or artificial mouth)
nominal setting: setting of the volume control where the RLR is as close as possible to -8 dB
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Ω Ohm
dB decibel
dBPa sound pressure level with respect to 1 Pa, expressed in dB
dBPa(A) "A" weighted sound pressure level with respect to 1 Pa, expressed in dB
dBV voltage level with respect to 1 V, expressed in dB
dBVp psophometrically weighted voltage level with respect to 1 V, expressed in dB
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10 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
a.c. alternating current
CSS Composite Source Signal
d.c. direct current
DECT Digital Enhanced Cordless Telecommunications
DRP ear Drum Reference Point
e.m.f. electromotive force
ERL Echo Return Loss
ERP Ear Reference Point
HATS Head And Torso Simulator
IEC International Electrotechnical Commission
ISO International Organisation for Standardisation
ITU-T International Telecommunications Union -Telecommunications sector
LRGP Loudness Rating Guard-ring Position
MRP Mouth Reference Point
Pa Pascal
PSTN Public Switched Telephone Network
r.m.s. root mean square
RL Return Loss
RLR Receiving Loudness Rating
RMS Root Mean Square
SLR Sending Loudness Rating
STMR SideTone Masking Rating
TE Terminal Equipment
V Volt
4 Speech transmission aspects
4.1 General
4.1.1 Polarity independence
Requirement: The TE shall conform to the requirements of the present document for both polarities of line feeding
voltage.
Test: Compliance shall be demonstrated by reversal of the d.c. voltage applied to the line terminals from test to test or
between changes of test configuration when performing the tests of clause 4.2.
4.1.2 Feed conditions
Requirement: The TE shall conform to the requirements of the present document when tested with a supply voltage of
50 V and with feed resistances ranging from 500 Ω to 2 800 Ω.
NOTE: Some requirements are only specified for single or specific values of feed resistance.
Test: Compliance shall be demonstrated by performing the tests of clause 4.2 with the feed resistances specified in this
clause.
4.1.3 Power supply
Requirement: Where the terminal handset function is intended to be used with power additional to that derived from
the network, the requirements of clause 4.2 shall apply only when such additional power is provided and operating
within specification.
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11 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
Test: Compliance shall be demonstrated by performing the tests of clause 4.2 with the power supply connected and
operative.
4.1.4 Volume control
Requirement: For TE with a user-controlled receiving volume control, the speech performance characteristics
requirements apply with the user-controlled receiving volume control at the setting where the RLR is as close as
possible to -8 dB, unless stated otherwise. This setting is to be taken as the nominal setting of the volume control.
Test: Compliance tests of clause 4.2 shall be carried out at the setting of the volume control where the RLR is as close
as possible to -8 dB when measured with the feed resistance R set to 1 000 Ω, unless otherwise specified in the
f
appropriate requirement.
NOTE: It is not necessary to strive to achieve values closer than 1 dB.
4.1.5 Test setup
Setup for handsets
The handset is placed in the HATS position as described in Recommendation ITU-T P.64 [2]. The artificial mouth shall
be conform with Recommendation ITU-T P.58 [12]. The artificial ear shall be conform with
Recommendation ITU-T P.57 [4], type 3.3 or type 3.4 ears shall be used.
Unless stated otherwise if a volume control is provided the setting is chosen such that the nominal RLR is met as close
as possible.
Position and calibration of HATS
All the sending and receiving characteristics shall be tested with the HATS, it shall be indicated what type of ear was
used at what application force. For handsets if not stated otherwise 8N application force shall be used.
The horizontal positioning of the HATS reference plane shall be guaranteed within ±2º.
The HATS shall be equipped with a type 3.3 or type 3.4 artificial ear for handsets.
For all measurements except RLR, this signal is diffuse field corrected as described in
Recommendation ITU-T P.58 [12] using the reverse nominal curve of table 3. For RLR measurement, it is corrected by
DRP to ERP correction as described in Recommendation ITU-T P.57 [4].
NOTE: For binaural headsets two artificial ears are required. The type 3.3 or type 3.4 artificial ears as specified in
Recommendation ITU-T P.57 [4] shall be used. The artificial ear shall be positioned on HATS according
to Recommendation ITU-T P.58 [12].
4.1.6 Environment for tests
The following conditions shall apply for the testing environment:
a) Ambient temperature: 15° C to 35° C (inclusive);
b) Relative humidity: 5 % to 85 %;
c) Air pressure: 86 kPa to 106 kPa (860 mbar to 1 060 mbar).
ETSI
12 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
4.1.7 Accuracy of measurements and test equipment setting
Unless specified otherwise, the accuracy of measurements made by test equipment shall be equal to or better than:
Table 4.1: Accuracy of measurements
Item Accuracy
Electrical signal level ±0,2 dB for levels ≥ -50 dBV
±0,4 dB for levels < -50 dBV
Sound pressure ±0,7 dB
Frequency
±0,2 %
Application force
±2 Newton
Unless specified otherwise, the accuracy of the signals generated by the test equipment shall be better than:
Table 4.2: Accuracy of signals
Quantity Accuracy
Sound pressure level at
±3 dB for frequencies from 100 Hz to 200 Hz
Mouth Reference Point (MRP)
±1 dB for frequencies from 200 Hz to 4 000 Hz
±3 dB for frequencies from 4 000 Hz to 8 000 Hz
Electrical excitation levels
±0,4 dB across the whole frequency range
Frequency generation ±2 % (see note)
Specified component values ±1 %
NOTE: This tolerance may be used to avoid measurements at critical frequencies, e.g. those
due to sampling operations within the terminal under test.

For terminal equipment which is directly powered from the mains supply, all tests shall be carried out within ±5 % of
the rated voltage of that supply. If the equipment is powered by other means and those means are not supplied as part of
the apparatus, all tests shall be carried out within the power supply limit declared by the supplier. If the power supply is
a.c., the test shall be conducted within ±4 % of the rated frequency.
4.1.8 Order of tests
Tests are made in any order except where otherwise specified.
Where testing involves taking measurements using different feeding resistances, measurements shall be made with the
highest feed resistance, then at lower values of resistance, decreasing sequentially to the minimum, in order to avoid a
heating effect in the test arrangement.
4.1.9 Acoustic environment
Acoustic tests shall be carried out in an environment where the ambient noise is insufficient to influence the acoustic
measurements being made.
Tests for noise and Echo Return Loss (ERL) shall be carried out in an environment where the ambient noise is less than
-64 dBPa (A).
4.1.10 Alternative test methods
The requirements of this test specification were written on the basis of the standard test methods described in the
present document. For some parameters it is recognized that alternative test methods may exist. It is the responsibility
of the test house to ensure that any alternative method used is equivalent to that described in the present document.
For TE with adaptive modification of any transmission parameter dependent on the electrical operating conditions
e.g. automatic adjustment of sidetone balance, each of the feed conditions for the compliance tests for the transmission
parameters should be treated as a new installation and should be conditioned according to any instructions provided by
the supplier.
ETSI
13 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
4.1.11 Testing arrangements
All tests for transmission performance shall be carried out with the TE connected to the test arrangement shown in
figure 4.1. The values of the feed resistance R are chosen appropriate to the requirement under test.
f
NOTE 1: The d.c. feeding circuit shown is an idealized arrangement. Performance requirements are given in
figures 4.3 and 4.5.
NOTE 2: The equipment used for testing is connected between A and B and consists of the following as
appropriate: a signal generator with an impedance of 600 Ω, a measuring set, the network either of
figures B.6, B.7, or B.8, or a 600 Ω resistor.
NOTE 3: The handset is placed in the HATS position as described in Recommendation ITU-T P.64 [2].The artificial
mouth shall be conform with Recommendation ITU-T P.58 [12].The artificial ear shall be conform with
Recommendation ITU-T P.57 [4], type 3.3 or type 3.4 ears shall be used.

Figure 4.1: Circuit for measurement of transmission characteristics
For sending measurements, signal is measured between A and B shown on figure 4.1.
For receiving measurements, signal is measured at the output of HATS's ear with corrections as given in clause 4.1.5.
ETSI
14 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
A C
C
f
L 600
ohms
f
ohms
B D
C
f
L
f
R
f
I
f
50 V
Figure 4.2: Insertion loss test arrangement for the d.c. feeding circuit
When measured with the circuit shown in figure 4.2, the insertion loss of the d.c. feeding circuit shown in figure 4.1
shall have a value less than that given in figure 4.3 for all resistances and frequencies at which it is used.
2 dB
1 dB
0,1 dB
10 20 50 100 200 500 1000 2 000 5 000 10 000 Hz

Figure 4.3: Maximum limit for insertion loss
ETSI
15 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
600 600
e=1V
ohms ohms
A C
C
f
L
ohms
f
U
ohms
B D
C
f L
f
R
f
I
f
50V
NOTE: In the absence of the d.c. feeding circuit, the return loss shall be greater than 40 dB.

Figure 4.4: Return loss test arrangement for the d.c. feeding circuit
When measured with the circuit shown in figure 4.4, the return loss of the d.c. feeding circuit shown in figure 4.1 shall
have a value greater than that given in figure 4.5 for all values of R and at all frequencies at which it is used.
f
The return loss (in dB) is calculated from the formula:
e
⎡ ⎤
RL = 20log
⎢ ⎥
2U
⎣ ⎦
where e is the generator voltage and U is the voltage measured by the measuring set.
dB
10 20 50 100 200 500 1 000 2 000 5 000 10 000 Hz

Figure 4.5: Minimum limit for return loss
ETSI
16 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
4.2 Speech performance characteristics
4.2.1 Sensitivity/frequency response
4.2.1.1 Sending Sensitivity
Requirement:
The sending sensitivity when measured according to Recommendation ITU-T P.64 [2] with a load of 600 Ω, as a
function of frequency, shall be not greater than the upper limit and not less than the lower limit given in table 4.1 and
shown in figure 4.6.
In case of handset connected to gateways intended to be used on very long analogue lines, preamphasis may be
accepted and the lower limit of the sending sensitivity response can be extended according to table 4.1.
Table 4.3: Co-ordinates of sending sensitivity limit curves
Extended lower
Frequency Upper Limit Lower Limit
limit
100 Hz -5 dB
300 Hz 5 dB -7 dB -11 dB
1 000 Hz 5 dB -5 dB -5 dB
3 400 Hz 5 dB -5 dB -5 dB
4 000 Hz 5 dB
NOTE: The limits for intermediate frequencies lie on a straight line drawn
between the given values on a linear (dB) - logarithmic (Hz) scale.

Figure 4.6: Sending sensitivity/frequency limits
ETSI
17 Final draft ETSI ES 203 038 V1.2.1 (2013-03)
Measurement method:
Compliance shall be checked by the test described below when measured with the feed resistance R set to 1 000 Ω.
f
The test signal to be used for the measurements shall be the artificial voice according to Recommendation ITU-T
P.50 [10]. If the signal to noise ratio in the high frequency domain is not sufficient Composite Source Signal (CSS) as
defined in Recommendation ITU-T P.501 [13] shall be used. The spectrum of acoustic signal produced by the HATS is
calibrated under free field conditions at the MRP. The test signal level shall be -4,7 dBPa, duration 20 s (10 s female,
10 s male voice), measured at the MRP. The test signal level is averaged over the complete test signal sequence.
The handset terminal is setup as described in clause 4.1.10. The handset is mounted according Recommendation ITU-T
P.64 [2]. The application force used to apply the handset against the artificial ear is 8N (with tolerance given in table 1
of Recommendation ITU-T P.64 [2]).
Measurements shall be made at one twelfth-octave intervals as given by the R.40 series of preferred numbers in
ISO 3 [6] for frequencies from 100 Hz to 8 kHz inclusive. For the calculation the averaged measured level at the
electrical reference point for each frequency band is referred to the averaged test signal level measured in each
frequency band at the MRP.
The sensitivity is expressed in terms of dBV/Pa.
4.2.1.2 Receiving Sensitivity
Requirement:
The receiving sensitivity when measured according to Recommendation ITU-T P.64 [2], as a function of frequency,
shall be not greater than the upper limit and not less than the lower limit given in table 2 and shown in figure 2 of
Recommendation ITU-T P.64 [2].
Table 4.4: Co-ordinates of recei
...

ETSI Standard
Speech and multimedia Transmission Quality (STQ);
Requirements and tests methods for terminal
equipment incorporating a handset when connected to the
analogue interface of the PSTN

2 ETSI ES 203 038 V1.2.1 (2013-05)

Reference
RES/STQ-203038
Keywords
analogue, PSTN, telephony, terminal
ETSI
650 Route des Lucioles
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© European Telecommunications Standards Institute 2013.
All rights reserved.
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DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
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of the 3GPP Organizational Partners.
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ETSI
3 ETSI ES 203 038 V1.2.1 (2013-05)
Contents
Intellectual Property Rights . 6
Foreword . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 8
2.2 Informative references . 8
3 Definitions, symbols and abbreviations . 9
3.1 Definitions . 9
3.2 Symbols . 9
3.3 Abbreviations . 10
4 Speech transmission aspects . 10
4.1 General . 10
4.1.1 Polarity independence . 10
4.1.2 Feed conditions . 10
4.1.3 Power supply . 10
4.1.4 Volume control . 11
4.1.5 Test setup . 11
4.1.6 Environment for tests . 11
4.1.7 Accuracy of measurements and test equipment setting . 12
4.1.8 Order of tests. 12
4.1.9 Acoustic environment . 12
4.1.10 Alternative test methods . 12
4.1.11 Testing arrangements . 13
4.2 Speech performance characteristics. 16
4.2.1 Sensitivity/frequency response . 16
4.2.1.1 Sending Sensitivity . 16
4.2.1.2 Receiving Sensitivity . 17
4.2.2 Sending and Receiving Loudness Ratings (SLR and RLR) . 19
4.2.2.1 Sending Loudness Rating (SLR) . 19
4.2.2.2 Receiving Loudness Rating (RLR) . 19
4.2.3 Sidetone . 20
4.2.4 Distortion . 21
4.2.4.1 Sending distortion . 21
4.2.4.2 Receiving distortion . 22
4.2.5 Linearity (variation of gain with input level) . 23
4.2.5.1 Sending linearity . 23
4.2.5.2 Receiving linearity . 23
4.2.6 Noise . 23
4.2.6.1 Sending noise . 23
4.2.6.2 Receiving noise . 24
4.2.7 Acoustic shock . 24
4.2.7.1 Continuous signal . 24
4.2.7.2 Peak signal . 24
4.2.8 Instability . 25
4.2.9 Echo Return Loss (ERL) . 26
Annex A (normative): Requirements for LRGP measured terminals . 28
A.1 Speech transmission aspects . 28
A.1.1 General . 28
A.1.1.1 Polarity independence . 28
A.1.1.2 Feed conditions . 28
A.1.1.3 Power supply . 28
ETSI
4 ETSI ES 203 038 V1.2.1 (2013-05)
A.1.1.4 Volume control . 28
A.2 Speech performance characteristics . 29
A.2.1 Sensitivity/frequency response . 29
A.2.1.1 Sending Sensitivity . 29
A.2.1.2 Receiving Sensitivity . 29
A.2.2 Sending and Receiving Loudness Ratings (SLR and RLR) . 30
A.2.2.1 Sending Loudness Rating (SLR) . 30
A.2.2.2 Receiving Loudness Rating (RLR) . 31
A.2.3 Sidetone . 31
A.2.4 Distortion . 31
A.2.4.1 Sending distortion . 31
A.2.4.2 Receiving distortion . 31
A.2.5 Linearity (variation of gain with input level) . 32
A.2.5.1 Sending linearity . 32
A.2.5.2 Receiving linearity . 32
A.2.6 Noise . 32
A.2.6.1 Sending noise . 32
A.2.6.2 Receiving noise . 32
A.2.7 Instability . 33
A.2.8 Echo Return Loss (ERL) . 33
Annex B (normative): Speech transmission compliance tests for LRGP measured terminals . 34
B.1 General conditions for testing . 34
B.1.1 Environment for tests . 34
B.1.2 Accuracy of measurements and test equipment setting . 34
B.1.3 Order of tests . 35
B.1.4 Acoustic environment . 35
B.1.5 Handset mounting. 35
B.1.6 Test levels . 35
B.1.6.1 Sending . 35
B.1.6.2 Receiving . 35
B.1.6.3 Sidetone . 35
B.1.7 Volume control . 35
B.1.8 Test equipment requirements . 36
B.1.9 Alternative test methods . 36
B.1.10 Testing arrangements . 36
B.2 Speech transmission performance tests for LRGP measured terminals . 39
B.2.1 Sensitivity/frequency response . 39
B.2.1.1 Sending sensitivity . 39
B.2.1.2 Receiving sensitivity . 39
B.2.2 Loudness ratings . 40
B.2.2.1 Sending loudness rating . 40
B.2.2.2 Receiving loudness rating . 40
B.2.3 Sidetone . 41
B.2.4 Distortion . 42
B.2.4.1 Sending distortion . 42
B.2.4.2 Receiving distortion . 43
B.2.5 Linearity (variation of gain with input level) . 43
B.2.5.1 Sending linearity . 43
B.2.5.2 Receiving linearity . 44
B.2.6 Noise . 44
B.2.6.1 Sending noise . 44
B.2.6.2 Receiving noise . 44
B.2.7 Instability . 45
B.2.8 Echo Return Loss (ERL) . 46
Annex C (informative): Table of changes relative to TBR 038 . 48
Annex D (informative): Overview on levels constraints for measurements . 51
ETSI
5 ETSI ES 203 038 V1.2.1 (2013-05)
Annex E (informative): Bibliography . 53
History . 54

ETSI
6 ETSI ES 203 038 V1.2.1 (2013-05)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
The present document has been produced by ETSI in order to update the contents of initial standards for PSTN
(e.g. TBR 038 [14]).
In particular, the update aims to take benefits of recent improvements in test methods and test equipments. Even the
purpose of the standard is to consider Narrowband speech characteristics and test methods, the new test methods leave
the door open for further services (e.g. wideband speech).
In this release 1 of the present document, no new measurement will be added except limitation of acoustic shock which
is a requirement for safety. Previous requirements and test methods are kept in an annex in order to be used for
terminals designed with LRGP method. Status of this annex is planned to be informative, but only in release 2.
The new measurements needed for handset terminal including speech processing functions will be introduced in a
further release taking into account this type of terminal.
Introduction
The present document specifies only the technical characteristics for handset telephony and is intended to be used in
conjunction with an appropriate access standard.
ETSI
7 ETSI ES 203 038 V1.2.1 (2013-05)
1 Scope
The present document specifies the technical characteristics (electrical and acoustic requirements and measurement
methods) to be provided by a single, handset telephony, terminal equipment which is intended for connection by 2 wires
to an analogue interface of a PSTN. This interface is characterized by a d.c. loop to indicate seizure and clearing, low
frequency a.c. ringing signals below the speech passband to indicate an incoming call and the transmission phase having
an approximate bandwidth of 3 kHz at the network terminating point.
The objective of the present document is to ensure minimum speech quality when interworking via the public network
between two single items of equipment.
The present document only applies to terminal equipment supporting handset telephony.
The present document is applicable to handset telephony function. In the case of multiple functions provided in the
same terminal equipment, the present document does not apply when those other functions are active in conjunction
with handset telephony.
The present document also applies to any type of analogue handset terminal intended to be connected to a gateway.
The present document specifies the functions necessary to provide 2-way real-time speech conversation. Where a
function is indicated as optional, it needs not to be provided, but, where such a function is provided, the terminal needs
to conform to the requirements and tests specified in the present document.
A test is given for each requirement in the present document including measurement methods. The terminal equipment
may be stimulated to perform the tests by additional equipment if necessary.
The present document gives requirements for new test methods based upon use of HATS and new tests signals.
In an annex, requirements with test methods corresponding to previous tests methods (LRGP) and test signals are given.
The application of the present document is intended also for handset telephony function employing a radio link
(e.g. DECT).
The application of the present document is not intended for:
• a handset telephony function with speech transmission performance specially designed for the less abled (e.g.
with amplification of received speech as an aid for the hard of hearing);
• a handset telephony function with speech transmission performance specifically designed to cater for hostile
environments;
• any handsfree or loudspeaking voice telephony function;
• a handset telephony function employing speech processing techniques other than coding.
NOTE: The terminal equipment may provide additional functions or facilities to those of handset telephony.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
ETSI
8 ETSI ES 203 038 V1.2.1 (2013-05)
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T G.122 (03/93): "Influence of national systems on stability and talker echo
in international connections".
[2] Recommendation ITU-T P.64 (11/07): "Determination of sensitivity/frequency characteristics of
local telephone systems".
[3] Recommendation ITU-T P.51 (08/96): "Artificial mouth".
[4] Recommendation ITU-T P.57 (11/05): "Artificial ears".
[5] IEC 651: "Sound level meters".
[6] ISO 3 (1973): "Preferred numbers - Series of preferred numbers".
[7] Recommendation ITU-T P.79 (11/07): "Calculation of loudness ratings for telephone sets".
[8] Recommendation ITU-T O.41 (10/94): "Psophometer for use on telephone-type circuits".
[9] Void.
[10] Recommendation ITU-T P.50 (09/99): "Artificial voices".
[11] Void.
[12] Recommendation ITU-T P 58 (08/96): "Head and torso simulator for telephony".
[13] Recommendation ITU-T P.501 (09/01): "Test signals for use in telephonometry".
[14] ETSI TBR 38 (05/98): "Public Switched Telephone Network (PSTN); Attachment requirements
for a terminal equipment incorporating an analogue handset function capable of supporting the
justified case service when connected to the analogue interface of the PSTN in Europe".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Void.
[i.2] ITU-T Recommendation P.35 (1988, Blue Book): "Handset telephones".
[i.3] Recommendation ITU-T P.65 (03/93): "Objective instrumentation for the determination of
loudness ratings".
[i.4] ETSI ES 202 738: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective
as perceived by the user".
[i.5] ETSI EG 202 518: "Speech and multimedia Transmission Quality (STQ); Acoustic Output of
Terminal Equipment; Maximum Levels and Test Methodology for Various Applications".
ETSI
9 ETSI ES 203 038 V1.2.1 (2013-05)
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
artificial ear: device for the calibration of earphones incorporating an acoustic coupler and a calibrated microphone for
the measurement of sound pressure and having an overall acoustic impedance similar to that of the average human ear
over a given frequency band
diffuse field equalization: equalization of the HATS sound pick-up, equalization of the difference, in dB, between the
spectrum level of the acoustic pressure at the ear Drum Reference Point (DRP) and the spectrum level of the acoustic
pressure at the HATS Reference Point (HRP) in a diffuse sound field with the HATS absent (application of reverse
nominal curve of table 3 in Recommendation ITU-T P.58 [12])
Echo Return Loss (ERL): return loss averaged with 1/f power weighting over the telephone band
(300 Hz to 3 400 Hz), in accordance with clause 4 of Recommendation ITU-T G.122 [1]
handset: combination of telephone microphone and receiver in a form convenient for holding simultaneously to mouth
and ear, which, when in use, retains the microphone in a position fixed in relation to the receiver
handset telephony: function provided by terminal equipment whereby two-way real-time speech is supported by
means of a handset that forms an integral part of the terminal equipment
NOTE: The term "live speech" is also frequently used to describe "real-time speech". For the purposes of the
present document, they should be considered as having the same meaning.
handsfree function: function whereby telephony transmission and reception is facilitated by the use of microphone(s)
and loudspeaker(s) placed at a distance from the user
NOTE: No handset is required to be used and normally the handset is not active.
Head And Torso Simulator (HATS) for telephonometry: manikin extending downward from the top of the head to
the waist, designed to simulate the sound pick-up characteristics and the acoustic diffraction produced by a median
human adult and to reproduce the acoustic field generated by the human mouth
loop state: state in which the TE draws sufficient DC current to activate the exchange
loop steady state: loop state excluding the transitions from and to quiescent state
loudness rating: measure, expressed in decibels, for characterizing the loudness performance of complete telephone
connections or of parts thereof such as sending system, line, receiving system
loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a
telephone receiver
Mouth Reference Point (MRP): point 25 mm in front of and on the axis of the lip position of a typical human mouth
(or artificial mouth)
nominal setting: setting of the volume control where the RLR is as close as possible to -8 dB
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Ω Ohm
dB decibel
dBPa sound pressure level with respect to 1 Pa, expressed in dB
dBPa(A) "A" weighted sound pressure level with respect to 1 Pa, expressed in dB
dBV voltage level with respect to 1 V, expressed in dB
dBVp psophometrically weighted voltage level with respect to 1 V, expressed in dB
ETSI
10 ETSI ES 203 038 V1.2.1 (2013-05)
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
a.c. alternating current
CSS Composite Source Signal
d.c. direct current
DECT Digital Enhanced Cordless Telecommunications
DRP ear Drum Reference Point
e.m.f. electromotive force
ERL Echo Return Loss
ERP Ear Reference Point
HATS Head And Torso Simulator
IEC International Electrotechnical Commission
ISO International Organisation for Standardisation
ITU-T International Telecommunications Union -Telecommunications sector
LRGP Loudness Rating Guard-ring Position
MRP Mouth Reference Point
Pa Pascal
PSTN Public Switched Telephone Network
r.m.s. root mean square
RL Return Loss
RLR Receiving Loudness Rating
RMS Root Mean Square
SLR Sending Loudness Rating
STMR SideTone Masking Rating
TE Terminal Equipment
V Volt
4 Speech transmission aspects
4.1 General
4.1.1 Polarity independence
Requirement: The TE shall conform to the requirements of the present document for both polarities of line feeding
voltage.
Test: Compliance shall be demonstrated by reversal of the d.c. voltage applied to the line terminals from test to test or
between changes of test configuration when performing the tests of clause 4.2.
4.1.2 Feed conditions
Requirement: The TE shall conform to the requirements of the present document when tested with a supply voltage of
50 V and with feed resistances ranging from 500 Ω to 2 800 Ω.
NOTE: Some requirements are only specified for single or specific values of feed resistance.
Test: Compliance shall be demonstrated by performing the tests of clause 4.2 with the feed resistances specified in this
clause.
4.1.3 Power supply
Requirement: Where the terminal handset function is intended to be used with power additional to that derived from
the network, the requirements of clause 4.2 shall apply only when such additional power is provided and operating
within specification.
ETSI
11 ETSI ES 203 038 V1.2.1 (2013-05)
Test: Compliance shall be demonstrated by performing the tests of clause 4.2 with the power supply connected and
operative.
4.1.4 Volume control
Requirement: For TE with a user-controlled receiving volume control, the speech performance characteristics
requirements apply with the user-controlled receiving volume control at the setting where the RLR is as close as
possible to -8 dB, unless stated otherwise. This setting is to be taken as the nominal setting of the volume control.
Test: Compliance tests of clause 4.2 shall be carried out at the setting of the volume control where the RLR is as close
as possible to -8 dB when measured with the feed resistance R set to 1 000 Ω, unless otherwise specified in the
f
appropriate requirement.
NOTE: It is not necessary to strive to achieve values closer than 1 dB.
4.1.5 Test setup
Setup for handsets
The handset is placed in the HATS position as described in Recommendation ITU-T P.64 [2]. The artificial mouth shall
be conform with Recommendation ITU-T P.58 [12]. The artificial ear shall be conform with
Recommendation ITU-T P.57 [4], type 3.3 or type 3.4 ears shall be used.
Unless stated otherwise if a volume control is provided the setting is chosen such that the nominal RLR is met as close
as possible.
Position and calibration of HATS
All the sending and receiving characteristics shall be tested with the HATS, it shall be indicated what type of ear was
used at what application force. For handsets if not stated otherwise 8N application force shall be used.
The horizontal positioning of the HATS reference plane shall be guaranteed within ±2º.
The HATS shall be equipped with a type 3.3 or type 3.4 artificial ear for handsets.
For all measurements except RLR, this signal is diffuse field corrected as described in
Recommendation ITU-T P.58 [12] using the reverse nominal curve of table 3. For RLR measurement, it is corrected by
DRP to ERP correction as described in Recommendation ITU-T P.57 [4].
NOTE: For binaural headsets two artificial ears are required. The type 3.3 or type 3.4 artificial ears as specified in
Recommendation ITU-T P.57 [4] shall be used. The artificial ear shall be positioned on HATS according
to Recommendation ITU-T P.58 [12].
4.1.6 Environment for tests
The following conditions shall apply for the testing environment:
a) Ambient temperature: 15° C to 35° C (inclusive);
b) Relative humidity: 5 % to 85 %;
c) Air pressure: 86 kPa to 106 kPa (860 mbar to 1 060 mbar).
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4.1.7 Accuracy of measurements and test equipment setting
Unless specified otherwise, the accuracy of measurements made by test equipment shall be equal to or better than:
Table 4.1: Accuracy of measurements
Item Accuracy
Electrical signal level ±0,2 dB for levels ≥ -50 dBV
±0,4 dB for levels < -50 dBV
Sound pressure ±0,7 dB
Frequency
±0,2 %
Application force
±2 Newton
Unless specified otherwise, the accuracy of the signals generated by the test equipment shall be better than:
Table 4.2: Accuracy of signals
Quantity Accuracy
Sound pressure level at
±3 dB for frequencies from 100 Hz to 200 Hz
Mouth Reference Point (MRP)
±1 dB for frequencies from 200 Hz to 4 000 Hz
±3 dB for frequencies from 4 000 Hz to 8 000 Hz
Electrical excitation levels
±0,4 dB across the whole frequency range
Frequency generation ±2 % (see note)
Specified component values ±1 %
NOTE: This tolerance may be used to avoid measurements at critical frequencies, e.g. those
due to sampling operations within the terminal under test.

For terminal equipment which is directly powered from the mains supply, all tests shall be carried out within ±5 % of
the rated voltage of that supply. If the equipment is powered by other means and those means are not supplied as part of
the apparatus, all tests shall be carried out within the power supply limit declared by the supplier. If the power supply is
a.c., the test shall be conducted within ±4 % of the rated frequency.
4.1.8 Order of tests
Tests are made in any order except where otherwise specified.
Where testing involves taking measurements using different feeding resistances, measurements shall be made with the
highest feed resistance, then at lower values of resistance, decreasing sequentially to the minimum, in order to avoid a
heating effect in the test arrangement.
4.1.9 Acoustic environment
Acoustic tests shall be carried out in an environment where the ambient noise is insufficient to influence the acoustic
measurements being made.
Tests for noise and Echo Return Loss (ERL) shall be carried out in an environment where the ambient noise is less than
-64 dBPa (A).
4.1.10 Alternative test methods
The requirements of this test specification were written on the basis of the standard test methods described in the
present document. For some parameters it is recognized that alternative test methods may exist. It is the responsibility
of the test house to ensure that any alternative method used is equivalent to that described in the present document.
For TE with adaptive modification of any transmission parameter dependent on the electrical operating conditions
e.g. automatic adjustment of sidetone balance, each of the feed conditions for the compliance tests for the transmission
parameters should be treated as a new installation and should be conditioned according to any instructions provided by
the supplier.
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4.1.11 Testing arrangements
All tests for transmission performance shall be carried out with the TE connected to the test arrangement shown in
figure 4.1. The values of the feed resistance R are chosen appropriate to the requirement under test.
f
NOTE 1: The d.c. feeding circuit shown is an idealized arrangement. Performance requirements are given in
figures 4.3 and 4.5.
NOTE 2: The equipment used for testing is connected between A and B and consists of the following as
appropriate: a signal generator with an impedance of 600 Ω, a measuring set, the network either of
figures B.6, B.7, or B.8, or a 600 Ω resistor.
NOTE 3: The handset is placed in the HATS position as described in Recommendation ITU-T P.64 [2].The artificial
mouth shall be conform with Recommendation ITU-T P.58 [12].The artificial ear shall be conform with
Recommendation ITU-T P.57 [4], type 3.3 or type 3.4 ears shall be used.

Figure 4.1: Circuit for measurement of transmission characteristics
For sending measurements, signal is measured between A and B shown on figure 4.1.
For receiving measurements, signal is measured at the output of HATS's ear with corrections as given in clause 4.1.5.
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A C
C
f
L 600
ohms
f
ohms
B D
C
f
L
f
R
f
I
f
50 V
Figure 4.2: Insertion loss test arrangement for the d.c. feeding circuit
When measured with the circuit shown in figure 4.2, the insertion loss of the d.c. feeding circuit shown in figure 4.1
shall have a value less than that given in figure 4.3 for all resistances and frequencies at which it is used.
2 dB
1 dB
0,1 dB
10 20 50 100 200 500 1000 2 000 5 000 10 000 Hz

Figure 4.3: Maximum limit for insertion loss
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600 600
e=1V
ohms ohms
A C
C
f
L
ohms
f
U
ohms
B D
C
f L
f
R
f
I
f
50V
NOTE: In the absence of the d.c. feeding circuit, the return loss shall be greater than 40 dB.

Figure 4.4: Return loss test arrangement for the d.c. feeding circuit
When measured with the circuit shown in figure 4.4, the return loss of the d.c. feeding circuit shown in figure 4.1 shall
have a value greater than that given in figure 4.5 for all values of R and at all frequencies at which it is used.
f
The return loss (in dB) is calculated from the formula:
e
⎡ ⎤
RL = 20log
⎢ ⎥
2U
⎣ ⎦
where e is the generator voltage and U is the voltage measured by the measuring set.
dB
10 20 50 100 200 500 1 000 2 000 5 000 10 000 Hz

Figure 4.5: Minimum limit for return loss
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4.2 Speech performance characteristics
4.2.1 Sensitivity/frequency response
4.2.1.1 Sending Sensitivity
Requirement:
The sending sensitivity when measured according to Recommendation ITU-T P.64 [2] with a load of 600 Ω, as a
function of frequency, shall be not greater than the upper limit and not less than the lower limit given in table 4.1 and
shown in figure 4.6.
In case of handset connected to gateways intended to be used on very long analogue lines, preamphasis may be
accepted and the lower limit of the sending sensitivity response can be extended according to table 4.1.
Table 4.3: Co-ordinates of sending sensitivity limit curves
Extended lower
Frequency Upper Limit Lower Limit
limit
100 Hz -5 dB
300 Hz 5 dB -7 dB -11 dB
1 000 Hz 5 dB -5 dB -5 dB
3 400 Hz 5 dB -5 dB -5 dB
4 000 Hz 5 dB
NOTE: The limits for intermediate frequencies lie on a straight line drawn
between the given values on a linear (dB) - logarithmic (Hz) scale.

Figure 4.6: Sending sensitivity/frequency limits
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Measurement method:
Compliance shall be checked by the test described below when measured with the feed resistance R set to 1 000 Ω.
f
The test signal to be used for the measurements shall be the artificial voice according to Recommendation ITU-T
P.50 [10]. If the signal to noise ratio in the high frequency domain is not sufficient Composite Source Signal (CSS) as
defined in Recommendation ITU-T P.501 [13] shall be used. The spectrum of acoustic signal produced by the HATS is
calibrated under free field conditions at the MRP. The test signal level shall be -4,7 dBPa, duration 20 s (10 s female,
10 s male voice), measured at the MRP. The test signal level is averaged over the complete test signal sequence.
The handset terminal is setup as described in clause 4.1.10. The handset is mounted according Recommendation ITU-T
P.64 [2]. The application force used to apply the handset against the artificial ear is 8N (with tolerance given in table 1
of Recommendation ITU-T P.64 [2]).
Measurements shall be made at one twelfth-octave intervals as given by the R.40 series of preferred numbers in
ISO 3 [6] for frequencies from 100 Hz to 8 kHz inclusive. For the calculation the averaged measured level at the
electrical reference point for each frequency band is referred to the averaged test signal level measured in each
frequency band at the MRP.
The sensitivity is expressed in terms of dBV/Pa.
4.2.1.2 Receiving Sensitivity
Requirement:
The receiving sensitivity when measured according to Recommendation ITU-T P.64 [2], as a function of frequency,
shall be not greater than the upper limit and not less than the lower limit given in table 2 and shown in figure 2 of
Recommendation ITU-T P.64 [2].
Table 4.4: Co-ordinates of receiving sensitivity limit curves
Frequency Upper Limit Lower Limit
100 Hz 6 dB
300 Hz 6 dB -8 dB
1 000 Hz 6 dB -6 dB
3 400 Hz 6 dB -6 dB
4 000 Hz 6 dB
NOTE 1: The limit curves shall be determined by straight lines joining successive
co-ordinates given in the tabl
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