ETSI ES 202 738 V1.8.1 (2020-05)

Speech and multimedia Transmission Quality (STQ); Transmission requirements for narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective as perceived by the user

RES/STQ-275

Kakovost prenosa govora in večpredstavnih vsebin (STQ) - Prenosne zahteve za ozkopasovne zvočniške in prostoročne terminale VoIP glede na kakovost storitev (QoS), kot jo dojema uporabnik

General Information

• Status: Not Published
• Technical Committee: STQ - Speech and multimedia Transmission Quality
• Current Stage: 12 - Completion
• Due Date: 19-May-2020
• Completion Date: 07-May-2020
• Ref Project: SIST ES 202 738 V1.8.1:2020 - Speech and multimedia Transmission Quality (STQ) - Transmission requirements for narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective as perceived by the user

Standards Content (Sample)

ETSI ES 202 738 V1.8.1 (2020-05)






ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for narrowband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user

---------------------- Page: 1 ----------------------
2 ETSI ES 202 738 V1.8.1 (2020-05)



Reference
RES/STQ-275
Keywords
handsfree, loudspeaking, narrowband, quality,
speech, terminal, VoIP

ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2020.
All rights reserved.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and
of the oneM2M Partners.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI

---------------------- Page: 2 ----------------------
3 ETSI ES 202 738 V1.8.1 (2020-05)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 General considerations . 10
4.1 Default Coding Algorithm . 10
4.2 End-to-end considerations . 10
5 Test equipment . 11
5.1 IP half channel measurement adaptor . 11
5.2 Environmental conditions for tests . 11
5.3 Accuracy of measurements and test signal generation . 11
5.4 Network impairment simulation . 12
5.5 Acoustic environment . 12
5.6 Influence of terminal delay on measurements . 12
6 Requirements and associated measurement methodologies . 13
6.1 Notes . 13
6.2 Test setup. 13
6.2.1 General . 13
6.2.2 Setup for terminal . 14
6.2.2.1 Hands-free measurements . 14
6.2.2.2 Measurements in loudspeaking mode . 18
6.2.3 Test signal levels . 18
6.2.3.1 Send. 18
6.2.3.2 Receive . 19
6.2.4 Setup of background noise simulation . 19
6.2.5 Setup for variable echo path . 20
6.3 Coding independent parameters . 20
6.3.1 Send frequency response . 20
6.3.2 Send Loudness Rating (SLR). 21
6.3.3 Mic mute . 22
6.3.4 Send distortion . 22
6.3.5 Out-of-band signals in send direction . 23
6.3.6 Send noise . 23
6.3.7 Terminal Coupling Loss weighted (TCLw) . 24
6.3.8 Stability loss. 24
6.3.9 Receive frequency response . 25
6.3.10 Receive Loudness Rating (RLR) . 27
6.3.11 Receive Distortion . 28
6.3.12 Out-of-band signals in receive direction . 29
6.3.13 Receive noise . 29
6.3.14 Double talk performance . 30
6.3.14.1 General . 30
6.3.14.2 Attenuation range in send direction during double talk A . 30
H,S,dt
6.3.14.3 Attenuation range in receive direction during double talk A . 31
H,R,dt
ETSI

---------------------- Page: 3 ----------------------
4 ETSI ES 202 738 V1.8.1 (2020-05)
6.3.14.4 Detection of echo components during double talk . 32
6.3.14.5 Minimum activation level and sensitivity of double talk detection . 33
6.3.15 Switching characteristics . 33
6.3.15.1 Note . 33
6.3.15.2 Activation in send direction . 33
6.3.15.3 Silence suppression and comfort noise generation . 34
6.3.16 Background noise performance . 34
6.3.16.1 Performance in send direction in the presence of background noise . 34
6.3.16.2 Speech quality in the presence of background noise . 35
6.3.16.3 Quality of background noise transmission (with far end speech). 36
6.3.17 Quality of echo cancellation . 36
6.3.17.1 Temporal echo effects . 36
6.3.17.2 Spectral echo attenuation . 37
6.3.17.3 Occurrence of artefacts . 38
6.3.17.4 Variable echo path. 38
6.3.18 Variant impairments . 38
6.3.18.1 Clock accuracy send . 38
6.3.18.2 Clock accuracy receive . 38
6.3.18.3 Send packet delay variation. 39
6.3.19 Send and receive delay - round trip delay . 39
6.4 Codec specific requirements. 41
6.4.1 Objective listening speech quality MOS-LQO in send direction . 41
6.4.2 Objective listening speech quality MOS-LQO in receive direction. 42
6.4.3 Quality of jitter buffer adjustment . 44
Annex A (informative): Processing delays in VoIP terminals . 46
Annex B (informative): Bibliography . 49
History . 50

ETSI

---------------------- Page: 4 ----------------------
5 ETSI ES 202 738 V1.8.1 (2020-05)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Traditionally, analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the fast
growth of IP networks, terminals directly interfacing packet-switched networks (VoIP) are being rapidly introduced.
Such IP network edge devices may include specifically designed IP phones, soft phones or other devices connected to
the IP based networks, providing telephony service. Since the IP networks will be in many cases interworking with the
traditional PSTN and private networks, many of the basic transmission requirements have to be harmonised with
specifications for traditional digital terminals. However, due to the unique characteristics of the IP networks including
packet loss, delay, etc. new performance specification, as well as appropriate measurement methods, will have to be
developed. Terminals are getting increasingly complex. Advanced signal processing is used to address the IP specific
issues. Also, the VoIP terminals may use other than 64 kbit/s PCM (Recommendation ITU-T G.711 [7]) speech coding
algorithms.
The advanced signal processing of terminals is targeted to speech signals. Therefore, wherever possible speech signals
are used for testing in order to achieve mostly realistic test conditions and meaningful results.
The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals.
NOTE: Requirement limits are given in tables, the associated curve when provided is given for illustration.
ETSI

---------------------- Page: 5 ----------------------
6 ETSI ES 202 738 V1.8.1 (2020-05)
1 Scope
The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio
terminals.
DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].
In contrast to other standards which define minimum performance requirements it is the intention of the present
document to specify terminal equipment requirements which enable manufacturers and service providers to enable good
quality end-to-end speech performance as perceived by the user.
In addition to basic testing procedures, the present document describes advanced testing procedures taking into account
further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.
2 References
2.1 Normative 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
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ETSI I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical characteristics of
telephony terminals; Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree
telephony".
[2] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full
Rate (EFR) speech transcoding (GSM 06.60)".
[3] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive
Multi-Rate - Wideband (AMR-WB) speech codec; General description (3GPP TS 26.171)".
[4] Recommendation ITU-T G.108: "Application of the E-model: A planning guide".
[5] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".
[6] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in
international connections".
[7] Recommendation ITU-T G.711: "Pulse code modulation (PCM) of voice frequencies".
[8] Recommendation ITU-T G.723.1: "Dual rate speech coder for multimedia communications
transmitting at 5.3 and 6.3 kbit/s".
[9] Recommendation ITU-T G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code
Modulation (ADPCM)".
[10] Recommendation ITU-T G.729: "Coding of speech at 8 kbit/s using conjugate-structure
algebraic-code-excited linear prediction (CS-ACELP)".
ETSI

---------------------- Page: 6 ----------------------
7 ETSI ES 202 738 V1.8.1 (2020-05)
[11] Recommendation ITU-T G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s
scalable wideband coder bitstream interoperable with G.729".
[12] Recommendation ITU-T O.41: "Psophometer for use on telephone-type circuits".
[13] Recommendation ITU-T P.50: "Artificial voices".
[14] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[15] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".
[16] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".
[17] Recommendation ITU-T P.310: "Transmission characteristics for narrow-band digital handset and
headset telephones".
[18] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[19] Recommendation ITU-T P.342: "Transmission characteristics for narrow-band digital
loudspeaking and hands-free telephony terminals".
[20] Recommendation ITU-T P.501: "Test signals for use in telephonometry".
[21] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using
complex test signals".
[22] Recommendation ITU-T P.581: "Use of head and torso simulator for hands-free and handset
terminal testing".
[23] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:
Specifications".
[24] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".
[25] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field
reproduction method for terminal testing including a background noise database".
[26] Recommendation ITU-T P.863.1: "Application guide for Recommendation ITU-T P.863".
[27] Recommendation ITU-T P.863: "Perceptual objective listening quality prediction".
[28] ETSI ES 202 737: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as
perceived by the user".
[29] Recommendation ITU-T P.1010: "Fundamental voice transmission objectives for VoIP terminals
and gateways".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
ETSI

---------------------- Page: 7 ----------------------
8 ETSI ES 202 738 V1.8.1 (2020-05)
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] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and
implementation of VoIP reference point".
[i.2] ETSI EG 202 396-3: "Speech and multimedia Transmission Quality (STQ); Speech Quality
performance in the presence of background noise; Part 3: Background noise
transmission - Objective test methods".
[i.3] Netem™.
NOTE: Information available at https://wiki.linuxfoundation.org/networking/netem.
[i.4] ETSI EG 201 377-1: "Speech and multimedia Transmission Quality (STQ); Specification and
measurement of speech transmission quality; Part 1: Introduction to objective comparison
measurement methods for one-way speech quality across networks".
[i.5] IETF RFC 4737: "Packet Reordering Metrics".
[i.6] ETSI EN 300 175-8: "Digital Enhanced Cordless Telecommunications (DECT); Common
Interface (CI); Part 8: Speech and audio coding and transmission".
[i.7] ETSI EN 300 176-2: "Digital Enhanced Cordless Telecommunications (DECT); Test
specification; Part 2: Audio and speech".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
artificial ear: device for the calibration of earphones incorporating an acoustic coupler and a calibrated microphone for
the measurement of the sound pressure and having an overall acoustic impedance similar to that of the median adult
human ear over a given frequency band
codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions
of transmission in the same equipment
ear-Drum Reference Point (DRP): point located at the end of the ear canal, corresponding to the ear-drum position
freefield equalization: artificial head is equalized in such a way that for frontal sound incidence in anechoic conditions
the frequency response of the artificial head is flat
freefield reference point: point located in the free sound field, at least in 1,5 m distance from a sound source radiating
in free air
NOTE: In case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head
present.
group audio terminal: handsfree terminal primarily designed for use by several users which will not be equipped with
a handset
handsfree telephony terminal: telephony terminal using a loudspeaker associated with an amplifier as a telephone
receiver and which can be used without a handset
HATS Hands-Free Reference Point (HATS HFRP): corresponds to a reference point "n" from Recommendation
ITU-T P.58 [15]: "n" is one of the points numbered from 11 to 17 and defined in table 6a of Recommendation ITU-T
P.58 [15] (coordinates of far field front point)
NOTE: The HATS HFRP depends on the location(s) of the microphones of the terminal under test: the
appropriate axis lip-ring/HATS HFRP is to be as close as possible to the axis lip-ring/HFT microphone
under test.
ETSI

---------------------- Page: 8 ----------------------
9 ETSI ES 202 738 V1.8.1 (2020-05)
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
loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a
telephone receiver
Mouth Reference Point (MRP): point located on axis and 25 mm in front of the lip plane of a mouth simulator
nominal setting of the volume control: setting which is closest to the nominal RLR
reordering: packet order changes during transfer over the network [i.5], packets arrive out of order at the receiver (i.e.
RTP packets)
softphone: speech communication system based upon a computer
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AM-FM Amplitude Modulation - Frequency Modulation
AMR Adaptative Multi-Rate
CS Composite Source
CSS Composite Source Signal
DRP ear Drum Reference Point
DUT Device Under Test
EC Echo Canceller
EFR Enhanced Full Rate
EL Echo Loss
ERP Ear Reference Point
FFT Fast Fourrier Transform
G-MOS-LQOn Overall transmission quality narrowband
GSM Global System for Mobile communications
HATS Head And Torso Simulator
HFRP Hands Free Reference Point
HFT Hands Free Terminal
IEC International Electrotechnical Commission
IP Internet Protocol
IPDV IP Packet Delay Variation
ITU-T International Telecommunication Union - Telecommunication standardization sector
LE Earphone coupling Loss
MOS Mean Opinion Score
MOS-LQOy Mean Opinion Score - Listening Quality Objective
NOTE: y being N for narrowband, M for mixed, S for super-wideband and F for fullband. See Recommendation
ITU-T P.800.1 [24].
MRP Mouth Reference Point
NLP Non Linear Processor
N-MOS-LQOn Transmission quality of the background noise narrowband
PBX Private Branch eXchange
PC Personal Computer
PCM Pulse Code Modulation
PDA Personal Digital Assistance
PMRP Sound Pressure at the Mouth Reference Point
PN Pseudo Noise
POI Point Of Interconnect
ETSI

--
...

Final draft ETSI ES 202 738 V1.8.1 (2020-03)






ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for narrowband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user

---------------------- Page: 1 ----------------------
2 Final draft ETSI ES 202 738 V1.8.1 (2020-03)



Reference
RES/STQ-275
Keywords
handsfree, loudspeaking, narrowband, quality,
speech, terminal, VoIP

ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2020.
All rights reserved.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and
of the oneM2M Partners.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI

---------------------- Page: 2 ----------------------
3 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 General considerations . 10
4.1 Default Coding Algorithm . 10
4.2 End-to-end considerations . 10
5 Test equipment . 11
5.1 IP half channel measurement adaptor . 11
5.2 Environmental conditions for tests . 11
5.3 Accuracy of measurements and test signal generation . 11
5.4 Network impairment simulation . 12
5.5 Acoustic environment . 12
5.6 Influence of terminal delay on measurements . 12
6 Requirements and associated measurement methodologies . 13
6.1 Notes . 13
6.2 Test setup. 13
6.2.1 General . 13
6.2.2 Setup for terminal . 14
6.2.2.1 Hands-free measurements . 14
6.2.2.2 Measurements in loudspeaking mode . 19
6.2.3 Test signal levels . 19
6.2.3.1 Send. 19
6.2.3.2 Receive . 20
6.2.4 Setup of background noise simulation . 20
6.2.5 Setup for variable echo path . 21
6.3 Coding independent parameters . 21
6.3.1 Send frequency response . 21
6.3.2 Send Loudness Rating (SLR). 22
6.3.3 Mic mute . 23
6.3.4 Send distortion . 23
6.3.5 Out-of-band signals in send direction . 24
6.3.6 Send noise . 24
6.3.7 Terminal Coupling Loss weighted (TCLw) . 25
6.3.8 Stability loss. 25
6.3.9 Receive frequency response . 26
6.3.10 Receive Loudness Rating (RLR) . 28
6.3.11 Receive Distortion . 29
6.3.12 Out-of-band signals in receive direction . 30
6.3.13 Receive noise . 30
6.3.14 Double talk performance . 31
6.3.14.1 General . 31
6.3.14.2 Attenuation range in send direction during double talk A . 31
H,S,dt
6.3.14.3 Attenuation range in receive direction during double talk A . 32
H,R,dt
ETSI

---------------------- Page: 3 ----------------------
4 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
6.3.14.4 Detection of echo components during double talk . 33
6.3.14.5 Minimum activation level and sensitivity of double talk detection . 34
6.3.15 Switching characteristics . 34
6.3.15.1 Note . 34
6.3.15.2 Activation in send direction . 34
6.3.15.3 Silence suppression and comfort noise generation . 35
6.3.16 Background noise performance . 35
6.3.16.1 Performance in send direction in the presence of background noise . 35
6.3.16.2 Speech quality in the presence of background noise . 36
6.3.16.3 Quality of background noise transmission (with far end speech). 37
6.3.17 Quality of echo cancellation . 37
6.3.17.1 Temporal echo effects . 37
6.3.17.2 Spectral echo attenuation . 38
6.3.17.3 Occurrence of artefacts . 39
6.3.17.4 Variable echo path. 39
6.3.18 Variant impairments . 39
6.3.18.1 Clock accuracy send . 39
6.3.18.2 Clock accuracy receive . 39
6.3.18.3 Send packet delay variation. 40
6.3.19 Send and receive delay - round trip delay . 40
6.4 Codec specific requirements. 43
6.4.1 Objective listening speech quality MOS-LQO in send direction . 43
6.4.2 Objective listening speech quality MOS-LQO in receive direction. 43
6.4.3 Quality of jitter buffer adjustment . 45
Annex A (informative): Processing delays in VoIP terminals . 47
Annex B (informative): Bibliography . 50
History . 51

ETSI

---------------------- Page: 4 ----------------------
5 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
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.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Traditionally, analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the fast
growth of IP networks, terminals directly interfacing packet-switched networks (VoIP) are being rapidly introduced.
Such IP network edge devices may include specifically designed IP phones, soft phones or other devices connected to
the IP based networks, providing telephony service. Since the IP networks will be in many cases interworking with the
traditional PSTN and private networks, many of the basic transmission requirements have to be harmonised with
specifications for traditional digital terminals. However, due to the unique characteristics of the IP networks including
packet loss, delay, etc. new performance specification, as well as appropriate measurement methods, will have to be
developed. Terminals are getting increasingly complex. Advanced signal processing is used to address the IP specific
issues. Also, the VoIP terminals may use other than 64 kbit/s PCM (Recommendation ITU-T G.711 [7]) speech coding
algorithms.
The advanced signal processing of terminals is targeted to speech signals. Therefore, wherever possible speech signals
are used for testing in order to achieve mostly realistic test conditions and meaningful results.
The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals.
NOTE: Requirement limits are given in tables, the associated curve when provided is given for illustration.
ETSI

---------------------- Page: 5 ----------------------
6 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
1 Scope
The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio
terminals.
DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].
In contrast to other standards which define minimum performance requirements it is the intention of the present
document to specify terminal equipment requirements which enable manufacturers and service providers to enable good
quality end-to-end speech performance as perceived by the user.
In addition to basic testing procedures, the present document describes advanced testing procedures taking into account
further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.
2 References
2.1 Normative 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
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ETSI I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical characteristics of
telephony terminals; Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree
telephony".
[2] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full
Rate (EFR) speech transcoding (GSM 06.60)".
[3] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive
Multi-Rate - Wideband (AMR-WB) speech codec; General description (3GPP TS 26.171)".
[4] Recommendation ITU-T G.108: "Application of the E-model: A planning guide".
[5] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".
[6] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in
international connections".
[7] Recommendation ITU-T G.711: "Pulse code modulation (PCM) of voice frequencies".
[8] Recommendation ITU-T G.723.1: "Dual rate speech coder for multimedia communications
transmitting at 5.3 and 6.3 kbit/s".
[9] Recommendation ITU-T G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code
Modulation (ADPCM)".
[10] Recommendation ITU-T G.729: "Coding of speech at 8 kbit/s using conjugate-structure
algebraic-code-excited linear prediction (CS-ACELP)".
ETSI

---------------------- Page: 6 ----------------------
7 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
[11] Recommendation ITU-T G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s
scalable wideband coder bitstream interoperable with G.729".
[12] Recommendation ITU-T O.41: "Psophometer for use on telephone-type circuits".
[13] Recommendation ITU-T P.50: "Artificial voices".
[14] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[15] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".
[16] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".
[17] Recommendation ITU-T P.310: "Transmission characteristics for narrow-band digital handset and
headset telephones".
[18] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[19] Recommendation ITU-T P.342: "Transmission characteristics for narrow-band digital
loudspeaking and hands-free telephony terminals".
[20] Recommendation ITU-T P.501: "Test signals for use in telephonometry".
[21] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using
complex test signals".
[22] Recommendation ITU-T P.581: "Use of head and torso simulator for hands-free and handset
terminal testing".
[23] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:
Specifications".
[24] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".
[25] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field
reproduction method for terminal testing including a background noise database".
[26] Recommendation ITU-T P.863.1: "Application guide for Recommendation ITU-T P.863".
[27] Recommendation ITU-T P.863: "Perceptual objective listening quality prediction".
[28] ETSI ES 202 737: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as
perceived by the user".
[29] Recommendation ITU-T P.1010: "Fundamental voice transmission objectives for VoIP terminals
and gateways".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
ETSI

---------------------- Page: 7 ----------------------
8 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
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] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and
implementation of VoIP reference point".
[i.2] ETSI EG 202 396-3: "Speech and multimedia Transmission Quality (STQ); Speech Quality
performance in the presence of background noise; Part 3: Background noise
transmission - Objective test methods".
[i.3] Netem™.
NOTE: Information available at https://wiki.linuxfoundation.org/networking/netem.
[i.4] ETSI EG 201 377-1: "Speech and multimedia Transmission Quality (STQ); Specification and
measurement of speech transmission quality; Part 1: Introduction to objective comparison
measurement methods for one-way speech quality across networks".
[i.5] IETF RFC 4737: "Packet Reordering Metrics".
[i.6] ETSI EN 300 175-8: "Digital Enhanced Cordless Telecommunications (DECT); Common
Interface (CI); Part 8: Speech and audio coding and transmission".
[i.7] ETSI EN 300 176-2: "Digital Enhanced Cordless Telecommunications (DECT); Test
specification; Part 2: Audio and speech".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
artificial ear: device for the calibration of earphones incorporating an acoustic coupler and a calibrated microphone for
the measurement of the sound pressure and having an overall acoustic impedance similar to that of the median adult
human ear over a given frequency band
codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions
of transmission in the same equipment
ear-Drum Reference Point (DRP): point located at the end of the ear canal, corresponding to the ear-drum position
freefield equalization: artificial head is equalized in such a way that for frontal sound incidence in anechoic conditions
the frequency response of the artificial head is flat
freefield reference point: point located in the free sound field, at least in 1,5 m distance from a sound source radiating
in free air
NOTE: In case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head
present.
group audio terminal: handsfree terminal primarily designed for use by several users which will not be equipped with
a handset
ETSI

---------------------- Page: 8 ----------------------
9 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
handsfree telephony terminal: telephony terminal using a loudspeaker associated with an amplifier as a telephone
receiver and which can be used without a handset
HATS Hands-Free Reference Point (HATS HFRP): corresponds to a reference point "n" from Recommendation
ITU-T P.58 [15]: "n" is one of the points numbered from 11 to 17 and defined in table 6a of Recommendation
ITU-T P.58 [15] (coordinates of far field front point)
NOTE: The HATS HFRP depends on the location(s) of the microphones of the terminal under test: the
appropriate axis lip-ring/HATS HFRP is to be as close as possible to the axis lip-ring/HFT microphone
under test.
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
loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a
telephone receiver
Mouth Reference Point (MRP): point located on axis and 25 mm in front of the lip plane of a mouth simulator
nominal setting of the volume control: setting which is closest to the nominal RLR
reordering: packet order changes during transfer over the network [i.5], packets arrive out of order at the receiver (i.e.
RTP packets)
softphone: speech communication system based upon a computer
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AM-FM Amplitude Modulation - Frequency Modulation
AMR Adaptative Multi-Rate
CS Composite Source
CSS Composite Source Signal
DRP ear Drum Reference Point
DUT Device Under Test
EC Echo Canceller
EFR Enhanced Full Rate
EL Echo Loss
ERP Ear Reference Point
FFT Fast Fourrier Transform
G-MOS-LQOn Overall transmission quality narrowband
GSM Global System for Mobile communications
HATS Head And Torso Simulator
HFRP Hands Free Reference Point
HFT Hands Free Terminal
IEC International Electrotechnical Commission
IP Internet Protocol
IPDV IP Packet Delay Variation
ITU-T International Telecommunication Union - Telecommunication standardization sector
LE Earphone coupling Loss
MOS Mean Opinion Score
MOS-LQOy Mean Opinion Score - Listening Quality Objective
NOTE: y being N for narrowband, M for mixed, S for super-wideband and F for fullband. See Recommendation
ITU-T P.800.1 [24].
ETSI

---------------------- Page: 9 ----------------------
10 Final draft ETSI ES 202 738 V1.8.1 (2020-03)
MRP Mouth Reference Point
NLP Non L
...

SLOVENSKI STANDARD
SIST ES 202 738 V1.8.1:2020
01-julij-2020
Kakovost prenosa govora in večpredstavnih vsebin (STQ) - Prenosne zahteve za
ozkopasovne zvočniške in prostoročne terminale VoIP glede na kakovost storitev
(QoS), kot jo dojema uporabnik
Speech and multimedia Transmission Quality (STQ) - Transmission requirements for
narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective as
perceived by the user
Ta slovenski standard je istoveten z: ETSI ES 202 738 V1.8.1 (2020-05)
ICS:
33.050.01 Telekomunikacijska Telecommunication terminal
terminalska oprema na equipment in general
splošno
SIST ES 202 738 V1.8.1:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ES 202 738 V1.8.1:2020

---------------------- Page: 2 ----------------------
SIST ES 202 738 V1.8.1:2020
ETSI ES 202 738 V1.8.1 (2020-05)






ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for narrowband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user

---------------------- Page: 3 ----------------------
SIST ES 202 738 V1.8.1:2020

2 ETSI ES 202 738 V1.8.1 (2020-05)



Reference
RES/STQ-275
Keywords
handsfree, loudspeaking, narrowband, quality,
speech, terminal, VoIP

ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2020.
All rights reserved.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and
of the oneM2M Partners.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI

---------------------- Page: 4 ----------------------
SIST ES 202 738 V1.8.1:2020

3 ETSI ES 202 738 V1.8.1 (2020-05)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 General considerations . 10
4.1 Default Coding Algorithm . 10
4.2 End-to-end considerations . 10
5 Test equipment . 11
5.1 IP half channel measurement adaptor . 11
5.2 Environmental conditions for tests . 11
5.3 Accuracy of measurements and test signal generation . 11
5.4 Network impairment simulation . 12
5.5 Acoustic environment . 12
5.6 Influence of terminal delay on measurements . 12
6 Requirements and associated measurement methodologies . 13
6.1 Notes . 13
6.2 Test setup. 13
6.2.1 General . 13
6.2.2 Setup for terminal . 14
6.2.2.1 Hands-free measurements . 14
6.2.2.2 Measurements in loudspeaking mode . 18
6.2.3 Test signal levels . 18
6.2.3.1 Send. 18
6.2.3.2 Receive . 19
6.2.4 Setup of background noise simulation . 19
6.2.5 Setup for variable echo path . 20
6.3 Coding independent parameters . 20
6.3.1 Send frequency response . 20
6.3.2 Send Loudness Rating (SLR). 21
6.3.3 Mic mute . 22
6.3.4 Send distortion . 22
6.3.5 Out-of-band signals in send direction . 23
6.3.6 Send noise . 23
6.3.7 Terminal Coupling Loss weighted (TCLw) . 24
6.3.8 Stability loss. 24
6.3.9 Receive frequency response . 25
6.3.10 Receive Loudness Rating (RLR) . 27
6.3.11 Receive Distortion . 28
6.3.12 Out-of-band signals in receive direction . 29
6.3.13 Receive noise . 29
6.3.14 Double talk performance . 30
6.3.14.1 General . 30
6.3.14.2 Attenuation range in send direction during double talk A . 30
H,S,dt
6.3.14.3 Attenuation range in receive direction during double talk A . 31
H,R,dt
ETSI

---------------------- Page: 5 ----------------------
SIST ES 202 738 V1.8.1:2020

4 ETSI ES 202 738 V1.8.1 (2020-05)
6.3.14.4 Detection of echo components during double talk . 32
6.3.14.5 Minimum activation level and sensitivity of double talk detection . 33
6.3.15 Switching characteristics . 33
6.3.15.1 Note . 33
6.3.15.2 Activation in send direction . 33
6.3.15.3 Silence suppression and comfort noise generation . 34
6.3.16 Background noise performance . 34
6.3.16.1 Performance in send direction in the presence of background noise . 34
6.3.16.2 Speech quality in the presence of background noise . 35
6.3.16.3 Quality of background noise transmission (with far end speech). 36
6.3.17 Quality of echo cancellation . 36
6.3.17.1 Temporal echo effects . 36
6.3.17.2 Spectral echo attenuation . 37
6.3.17.3 Occurrence of artefacts . 38
6.3.17.4 Variable echo path. 38
6.3.18 Variant impairments . 38
6.3.18.1 Clock accuracy send . 38
6.3.18.2 Clock accuracy receive . 38
6.3.18.3 Send packet delay variation. 39
6.3.19 Send and receive delay - round trip delay . 39
6.4 Codec specific requirements. 41
6.4.1 Objective listening speech quality MOS-LQO in send direction . 41
6.4.2 Objective listening speech quality MOS-LQO in receive direction. 42
6.4.3 Quality of jitter buffer adjustment . 44
Annex A (informative): Processing delays in VoIP terminals . 46
Annex B (informative): Bibliography . 49
History . 50

ETSI

---------------------- Page: 6 ----------------------
SIST ES 202 738 V1.8.1:2020

5 ETSI ES 202 738 V1.8.1 (2020-05)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Traditionally, analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the fast
growth of IP networks, terminals directly interfacing packet-switched networks (VoIP) are being rapidly introduced.
Such IP network edge devices may include specifically designed IP phones, soft phones or other devices connected to
the IP based networks, providing telephony service. Since the IP networks will be in many cases interworking with the
traditional PSTN and private networks, many of the basic transmission requirements have to be harmonised with
specifications for traditional digital terminals. However, due to the unique characteristics of the IP networks including
packet loss, delay, etc. new performance specification, as well as appropriate measurement methods, will have to be
developed. Terminals are getting increasingly complex. Advanced signal processing is used to address the IP specific
issues. Also, the VoIP terminals may use other than 64 kbit/s PCM (Recommendation ITU-T G.711 [7]) speech coding
algorithms.
The advanced signal processing of terminals is targeted to speech signals. Therefore, wherever possible speech signals
are used for testing in order to achieve mostly realistic test conditions and meaningful results.
The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals.
NOTE: Requirement limits are given in tables, the associated curve when provided is given for illustration.
ETSI

---------------------- Page: 7 ----------------------
SIST ES 202 738 V1.8.1:2020

6 ETSI ES 202 738 V1.8.1 (2020-05)
1 Scope
The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio
terminals.
DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].
In contrast to other standards which define minimum performance requirements it is the intention of the present
document to specify terminal equipment requirements which enable manufacturers and service providers to enable good
quality end-to-end speech performance as perceived by the user.
In addition to basic testing procedures, the present document describes advanced testing procedures taking into account
further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.
2 References
2.1 Normative 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
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ETSI I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical characteristics of
telephony terminals; Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree
telephony".
[2] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full
Rate (EFR) speech transcoding (GSM 06.60)".
[3] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive
Multi-Rate - Wideband (AMR-WB) speech codec; General description (3GPP TS 26.171)".
[4] Recommendation ITU-T G.108: "Application of the E-model: A planning guide".
[5] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".
[6] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in
international connections".
[7] Recommendation ITU-T G.711: "Pulse code modulation (PCM) of voice frequencies".
[8] Recommendation ITU-T G.723.1: "Dual rate speech coder for multimedia communications
transmitting at 5.3 and 6.3 kbit/s".
[9] Recommendation ITU-T G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code
Modulation (ADPCM)".
[10] Recommendation ITU-T G.729: "Coding of speech at 8 kbit/s using conjugate-structure
algebraic-code-excited linear prediction (CS-ACELP)".
ETSI

---------------------- Page: 8 ----------------------
SIST ES 202 738 V1.8.1:2020

7 ETSI ES 202 738 V1.8.1 (2020-05)
[11] Recommendation ITU-T G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s
scalable wideband coder bitstream interoperable with G.729".
[12] Recommendation ITU-T O.41: "Psophometer for use on telephone-type circuits".
[13] Recommendation ITU-T P.50: "Artificial voices".
[14] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[15] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".
[16] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".
[17] Recommendation ITU-T P.310: "Transmission characteristics for narrow-band digital handset and
headset telephones".
[18] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[19] Recommendation ITU-T P.342: "Transmission characteristics for narrow-band digital
loudspeaking and hands-free telephony terminals".
[20] Recommendation ITU-T P.501: "Test signals for use in telephonometry".
[21] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using
complex test signals".
[22] Recommendation ITU-T P.581: "Use of head and torso simulator for hands-free and handset
terminal testing".
[23] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:
Specifications".
[24] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".
[25] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field
reproduction method for terminal testing including a background noise database".
[26] Recommendation ITU-T P.863.1: "Application guide for Recommendation ITU-T P.863".
[27] Recommendation ITU-T P.863: "Perceptual objective listening quality prediction".
[28] ETSI ES 202 737: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as
perceived by the user".
[29] Recommendation ITU-T P.1010: "Fundamental voice transmission objectives for VoIP terminals
and gateways".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
ETSI

---------------------- Page: 9 ----------------------
SIST ES 202 738 V1.8.1:2020

8 ETSI ES 202 738 V1.8.1 (2020-05)
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] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and
implementation of VoIP reference point".
[i.2] ETSI EG 202 396-3: "Speech and multimedia Transmission Quality (STQ); Speech Quality
performance in the presence of background noise; Part 3: Background noise
transmission - Objective test methods".
[i.3] Netem™.
NOTE: Information available at https://wiki.linuxfoundation.org/networking/netem.
[i.4] ETSI EG 201 377-1: "Speech and multimedia Transmission Quality (STQ); Specification and
measurement of speech transmission quality; Part 1: Introduction to objective comparison
measurement methods for one-way speech quality across networks".
[i.5] IETF RFC 4737: "Packet Reordering Metrics".
[i.6] ETSI EN 300 175-8: "Digital Enhanced Cordless Telecommunications (DECT); Common
Interface (CI); Part 8: Speech and audio coding and transmission".
[i.7] ETSI EN 300 176-2: "Digital Enhanced Cordless Telecommunications (DECT); Test
specification; Part 2: Audio and speech".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
artificial ear: device for the calibration of earphones incorporating an acoustic coupler and a calibrated microphone for
the measurement of the sound pressure and having an overall acoustic impedance similar to that of the median adult
human ear over a given frequency band
codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions
of transmission in the same equipment
ear-Drum Reference Point (DRP): point located at the end of the ear canal, corresponding to the ear-drum position
freefield equalization: artificial head is equalized in such a way that for frontal sound incidence in anechoic conditions
the frequency response of the artificial head is flat
freefield reference point: point located in the free sound field, at least in 1,5 m distance from a sound source radiating
in free air
NOTE: In case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head
present.
group audio terminal: handsfree terminal primarily designed for use by several users which will not be equipped with
a handset
handsfree telephony terminal: telephony terminal using a loudspeaker associated with an amplifier as a telephone
receiver and which can be used without a handset
HATS Hands-Free Reference Point (HATS HFRP): corresponds to a reference point "n" from Recommendation
ITU-T P.58 [15]: "n" is one of the points numbered from 11 to 17 and defined in table 6a of Recommendation ITU-T
P.58 [15] (coordinates of far field front point)
NOTE: The HATS HFRP depends on the location(s) of the microphones of the terminal under test: the
appropriate axis lip-ring/HATS HFRP is to be as close as possible to the axis lip-ring/HFT microphone
under test.
ETSI

---------------------- Page: 10 ----------------------
SIST ES 202 738 V1.8.1:2020

9 ETSI ES 202 738 V1.8.1 (2020-05)
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
loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a
telephone receiver
Mouth Reference Point (MRP): point located on axis and 25 mm in front of the lip plane of a mouth simulator
nominal setting of the volume control: setting which is closest to the nominal RLR
reordering: packet order changes during transfer over the network [i.5], packets arrive out of order at the receiver (i.e.
RTP packets)
softphone: speech communication system based upon a computer
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AM-FM Amplitude Modulation - Frequency Modulation
AMR Adapta
...