ETSI ETS 300 175-8 ed.2 (1996-09)

Digital Enhanced Cordless Telecommunications (DECT); Common Interface (CI); Part 8: Speech coding and transmission

RE/RES-03027-8

Digitalne izboljšane brezvrvične telekomunikacije (DECT) - Skupni vmesnik (CI) - 8. del: Kodiranje in prenos govora

General Information

• Status: Published
• Publication Date: 19-Sep-1996
• Technical Committee: RES 3 - DECT
• Current Stage: 13 - TB decision to make document historical
• Completion Date: 28-Sep-2001
• Ref Project: SIST ETS 300 175-8:1999 - Digital Enhanced Cordless Telecommunications (DECT); Common Interface (CI); Part 8: Speech coding and transmission

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital Enhanced Cordless Telecommunications (DECT); Common Interface (CI); Part 8: Speech coding and transmission33.070.30'(&7Digital Enhanced Cordless Telecommunications (DECT)ICS:Ta slovenski standard je istoveten z:ETS 300 175-8 E23SIST ETS 300 175-8:199en01-GHFHPEHU1993SIST ETS 300 175-8:199SLOVENSKI
STANDARD



SIST ETS 300 175-8:1999



EUROPEANETS 300 175-8TELECOMMUNICATIONSeptember 1996STANDARDSecond EditionSource: ETSI TC-RESReference: RE/RES-03027-8ICS:33.060, 33.060.50Key words:DECT, radioRadio Equipment and Systems (RES);Digital Enhanced Cordless Telecommunications (DECT);Common Interface (CI);Part 8: Speech coding and transmissionETSIEuropean Telecommunications Standards InstituteETSI SecretariatPostal address: F-06921 Sophia Antipolis CEDEX - FRANCEOffice address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCEX.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail].: [phone] - Fax: [phone]Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and theforegoing restriction extend to reproduction in all media.© European Telecommunications Standards Institute 1996. All rights reserved.SIST ETS 300 175-8:1999



Page 2ETS 300 175-8: September 1996Whilst every care has been taken in the preparation and publication of this document, errors in content,typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to"ETSI Editing and Committee Support Dept." at the address shown on the title page.SIST ETS 300 175-8:1999



Page 3ETS 300 175-8: September 1996ContentsForeword.71Scope.92Normative references.93Definitions and abbreviations.113.1Definitions.113.2Abbreviations.124Configurations.134.1Reference configuration.134.1.1Basic configuration.134.1.2Portable Part (PP).144.1.2.1Functional organization.144.1.2.2Volume control.154.1.3Fixed Part (FP).154.1.3.1Digital interface.154.1.3.2Analogue interface.164.1.3.3FP adaptive volume control.164.2Test configurations.165Encoding.175.132 kbit/s full term (ADPCM).175.1.1Algorithm.175.1.2Bit sequence.175.2Other codings.176Transmission aspects.176.1Relative level.176.2Acoustic reference level.176.3Volume control.177Speech performance characteristics.187.1PP frequency responses.187.1.1Sending.187.1.2Receiving.187.2PP sending and receiving loudness ratings.187.2.1Nominal values.187.2.2User-controlled volume control in PP.197.2.3PP adaptive volume control.197.2.4FP adaptive volume control.207.3Sidetone.207.3.1Talker sidetone.207.3.2Listener sidetone.207.4Terminal coupling loss.217.4.1Weighted Terminal Coupling Loss (TLCw).217.4.1.1PP for the 3,1 kHz service (PSTN or ISDN).217.4.1.2FP with 4-wire interface.217.4.1.3FP with analogue 2-wire interface.227.4.1.4PP for unrestricted 64 kbit/s service.227.4.2Stability loss.227.4.2.1Requirement.227.4.2.2Test conditions.22SIST ETS 300 175-8:1999



Page 4ETS 300 175-8: September 19967.4.2.3Fixed geometry PP.227.4.2.4Variable geometry PP.227.5Distortion.237.5.1Sending.237.5.2Receiving.237.5.3Sidetone.237.5.4Recommended value for network planning.237.6Out of band signals.237.6.1Sending (discrimination against out of band input signals).237.6.2Receiving (spurious out of band signals).237.7Noise.247.7.1Sending.247.7.2Narrow-band noise.247.7.3Receiving.247.7.4Level of sampling frequency (receiving).247.8Acoustic shock.247.8.1Continuous signal.247.8.2Peak signal.247.9Delay.247.9.1DECT network.247.9.2PP.247.9.3FP.247.10Network echo control.257.11PP ambient noise rejection.258Additional features.268.1Loudspeaking and hand-free facilities.268.2Tandem with mobile radio network.268.2.1Tandem with GSM.268.2.1.1Network echo control.268.2.1.2Terminal coupling loss.268.2.1.3The GSM mobile transmitter operates in continuous mode.268.2.1.4The GSM mobile transmitter operates in discontinuousmode, DTX.268.3DECT connected to the GSM fixed network.278.3.1Network echo control.278.3.2Terminal coupling loss.278.4Wireless Relay Stations (WRS).278.4.1Modified FP network echo control requirements for implementation of 2and 3 CRFP links in cascade.28Annex A (informative):Description of "reference" echo control devices.29A.1Handset echo.29A.1.1Overview.29A.1.1.1Connection to the PSTN/ISDN.29A.1.1.1.1Local and national calls.29A.1.1.1.2Long distance connections with echo control devices in thePSTN/ISDN, e.g. calls via satellites.29A.1.1.2Connection to the GSM network.30A.1.2Implementation of the FP echo control function subclause 7.4.1.2 b.30A.1.2.1Suppression threshold.30A.1.2.2Static characteristics of activation control.31A.1.2.3Dynamic characteristics of activation control.31A.2Network echo.31A.2.1Soft suppressor implementation of requirement 2 of subclause 7.10.32A.2.1.1Static characteristics.32A.2.1.2Dynamic characteristics.32A.2.2Additional echo control for a 2-wire interface of requirement 1 of subclause 7.10.32SIST ETS 300 175-8:1999



Page 5ETS 300 175-8: September 1996A.2.3Echo canceller used for both requirements 1 and 2.33Annex B (informative):Local loop application.34B.1DECT tethered local loop replacement with 2-wire PP end system.34B.1.1TCLw requirements.34B.1.2Network echo.35B.2Quantization distortion considerations.35Annex C (informative):GSM Discontinuous Transmission (DTX), and Voice Activity Detection (VAD).36Annex D (informative):Speech levels in relation to ambient room noise and examples of adaptivevolume control settings.37Annex E (informative):Bibliography.38History.39SIST ETS 300 175-8:1999



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Page 7ETS 300 175-8: September 1996ForewordThis second edition European Telecommunication Standard (ETS) has been produced by the RadioEquipment and Systems (RES) Technical Committee of the European Telecommunications StandardsInstitute (ETSI).This ETS forms part 8 of a series of 9 laying down the arrangements for the Digital Enhanced CordlessTelecommunications (DECT) Common Interface (CI).Part 1:"Overview".Part 2"Physical layer (PHL)".Part 3"Medium Access Control (MAC) layer".Part 4"Data Link Control (DLC) layer".Part 5:"Network (NWK) layer".Part 6:"Identities and addressing".Part 7:"Security features".Part 8:"Speech coding and transmission".Part 9:"Public Access Profile (PAP)".Further details of the DECT system may be found in ETR 015, ETR 043, and ETR 056 (see annex E).Transposition datesDate of adoption of this ETS:6 September 1996Date of latest announcement of this ETS (doa):31 December 1996Date of latest publication of new National Standardor endorsement of this ETS (dop/e):30 June 1997Date of withdrawal of any conflicting National Standard (dow):30 June 1997SIST ETS 300 175-8:1999



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Page 9ETS 300 175-8: September 19961ScopeThis second edition European Telecommunication Standard (ETS) is part of the Digital Enhanced CordlessTelecommunications (DECT) Common Interface (CI) and specifies the speech coding and transmissionrequirements.In order to ensure satisfactory interworking of different portable and fixed units, it is necessary to specifythe transmission performance of the analogue information over the digital link. This requires not only use ofa common speech algorithm, but also standardization of frequency responses, reference speech levels (orloudness) at the air interface and various other parameters.This ETS applies to DECT equipment which includes all the necessary functions to provide real-timetwo-way speech conversation. A 3,1 kHz telephony teleservice conveyed over a DECT link (including FixedPart (FP) and Portable Part (PP)) which is capable of being connected (directly or indirectly) to the publicnetwork access point has to comply with the requirements in this ETS.Tethered fixed point local loop applications are not required to comply with the requirements of this part.The speech performance characteristics defined in this ETS typically conform to ETS 300 085 [19], whichspecifies the overall performance between the handset acoustic interface and a 64 kbit/s A-law PulseCode Modulated (PCM) digital network interface. The deviations from ETS 300 085 [19] are mainly due tothe consequences of non-PCM coding and transmission delay.The additional features described in clause 8 are those which are not included in ETS 300 085 [19], butwhich are likely to occur in a DECT system: analogue interface, loudspeaking and hand-free facilities,tandeming with a mobile radio network. Headsets are not covered by the present specifications.For the DECT systems which connect to the Public Switched Telephone Network (PSTN) via an analogueinterface, this ETS includes the basics on which the national specifications can be built, referring toETS 300 001 [20] (which specifies the connection of terminal equipments to the PSTN via a 2-wireanalogue interface) and the appropriate national standard.ETSI/STC TM5 has prepared a technical report, ETR 041, to be used as a guide for network planning.A summary of the control and the use of the DECT echo control functions, to guide on need for options tomanufacturers and installers, is found in the supplementary services clause of ETR 056.Information concerning test methods can be found in I-ETS 300 176 [9]. The test methods take intoaccount that DECT is a digital system.2Normative referencesThis ETS incorporates, by dated or undated reference, provisions from other publications. These normativereferences are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this ETSonly when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies.[1]ETS 300 175-1 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 1:Overview".[2]ETS 300 175-2 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 2: PhysicalLayer (PHL)".[3]ETS 300 175-3 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 3: MediumAccess Control (MAC) layer".SIST ETS 300 175-8:1999



Page 10ETS 300 175-8: September 1996[4]ETS 300 175-4 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 4: DataLink Control (DLC) layer".[5]ETS 300 175-5 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 5: Network(NWK) layer".[6]ETS 300 175-6 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 6: Identitiesand addressing".[7]ETS 300 175-7 (1996): "Radio Equipment and Systems (RES); Digital EuropeanCordless Telecommunications (DECT); Common Interface (CI); Part 7: Securityfeatures".[8]ETS 300 444: "Radio Equipment and Systems (RES); Digital European CordlessTelecommunications (DECT): Generic Access Profile (GAP)".[9]I-ETS 300 176: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Approval test specification".[10]CCITT Recommendation G.101 (1988): "The transmission plan".[11]CCITT
Recommendation G.131 (1988): "Stability and echo".[12]CCITT Recommendation G.164 (1988): "Echo suppressors".[13]CCITT Recommendation G.165 (1988): "Echo cancellers".[14]CCITT Recommendation G.701 (1988): "Vocabulary of digital transmission andmultiplexing, and pulse code modulation (PCM) terms".[15]CCITT Recommendation G.726 (1991): "40, 32, 24, 16 kbit/s adaptivedifferential pulse code modulation (ADPCM)".[16]CCITT Recommendation I.241 (1988): "Teleservices supported by an ISDN".[17]CCITT Recommendation P.10 (1988): "Vocabulary of terms on telephonetransmission quality and telephone sets".[18]CCITT Recommendation P.34 (1988): "Transmission characteristics ofhands-free telephones".[19]ETS 300 085: "Integrated Services Digital Network (ISDN): 3,1 kHz telephonyteleservice; Attachment requirements for handset terminals" (text relevant forNET 33).[20]ETS 300 001: "Attachments to Public Switched Telephone Network (PSTN);General technical requirements for equipment connected to an analoguesubscriber interface in the PSTN" (Candidate NET 4).[21]CCITT Recommendation G.113 (1988): "Transmission impairments".[22]CCITT Recommendation G.111 (1988): "Loudness ratings (LRs) in aninternational connection".[23]ETS 300 540: "Digital cellular telecommunications system (Phase 2);Transmission planning aspects of the speech service in the GSM Public LandMobile Network (PLMN) system (GSM 03.50)".SIST ETS 300 175-8:1999



Page 11ETS 300 175-8: September 19963Definitions and abbreviations3.1DefinitionsFor the purposes of this ETS, the following definitions apply:Central Control Fixed Part (CCFP): See ETS 300 175-1 [1].Cordless Radio Fixed Part (CRFP): See ETS 300 175-1 [1].DECT Network (DNW): See ETS 300 175-1 [1].double duplex bearer : See ETS 300 175-1 [1].End System (ES): See ETS 300 175-1 [1].fixed geometry Portable Part (PP): A PP in which the electro-acoustic transducers and their associatedacoustic components are held in fixed relative positions and/or orientations during all on-line conditions andtest conditions of the PP.Fixed Part (DECT Fixed Part) (FP): See ETS 300 175-1 [1].Fixed radio Termination (FT): See ETS 300 175-1 [1].Generic Access Profile (GAP): A standard in addition to the DECT CI that ensures interoperabilitybetween FPs and PPs from different manufacturers.handset echo: The echo, perceptible by the far-end user, resulting from the coupling between thereceiving and sending directions of the handset, mostly due to acoustic coupling between transducers. It isparticularly objectionable in communications including a satellite and an echo canceller, as the DECThandset echo may be out of range of the echo canceller.network (telecommunication network): See ETS 300 175-1 [1].network echo: The echo, perceptible by the DECT user, resulting from reflections in the network. It ismostly due to hybrid impairments at both ends of the communication.operator (DECT operator): See ETS 300 175-1 [1].Portable Handset (PHS): See ETS 300 175-1 [1].Portable Part (DECT Portable Part) (PP): See ETS 300 175-1 [1].Portable radio Termination (PT): See ETS 300 175-1 [1].public: See ETS 300 175-1 [1].public access service: See ETS 300 175-1 [1].Radio Fixed Part (RFP): See ETS 300 175-1 [1].Repeater Part (REP) : See ETS 300 175-1 [1].service provider (telecommunications service provider): See ETS 300 175-1 [1].telephony service: See CCITT Recommendation I.241 [16].user (of a telecommunication network): See ETS 300 175-1 [1].SIST ETS 300 175-8:1999



Page 12ETS 300 175-8: September 1996variable geometry PP: A PP that allows the position and/or orientation of its electro-acoustic transducersand their associated acoustic components to be changed during all on-line conditions of the PP.Wireless Relay Station (WRS): See ETS 300 175-1 [1].3.2AbbreviationsFor the purposes of this ETS, relevant definitions and abbreviations in CCITT Recommendations P.10 [17]and G.701 [14] apply. In addition the following abbreviations apply:ADPCMAdaptive Differential Pulse Code ModulationARLAcoustic Reference LevelCCFPCentral Control Fixed PartCICommon InterfaceCFRPCordless Radio Fixed PartCLRRCircuit Loudness Rating, ReceivingCLRSCircuit Loudness Rating, SendingCODECCoder-DecoderCRFPCordless Radio Fixed PartCSPDNCircuit Switched Public Data NetworkdBmdB relative to 1 milliwattdBm0The absolute power level in decibels referred to a point of zero relative leveldBrThe relative power level in decibelsDECTDigital Enhanced Cordless TelecommunicationsDNWDECT NetworkERPEar Reference PointESEnd SystemFPFixed PartFTFixed radio TerminationGAPGeneric Access ProfileISDNIntegrated Services Digital NetworkLELocal EchoLSTRListener Sidetone RatingMRPMouth Reference PointNLPNon-Linear ProcessorNWKNetworkOLROverall Loudness RatingP(A)BXPrivate (Automatic) Branch ExchangePAPPublic Access ProfilePHSPortable HandsetPPPortable PartPSPDNPacket Switched Public Data NetworkPSTNPublic Switched Telephone NetworkPTPortable radio TerminationPTNPrivate Telecommunication NetworkReFPReference Fixed PartRePPReference Portable PartREPREpeater PartRFPRadio Fixed PartRLRHReceiving Loudness Rating of the HandsetSLRHSending Loudness Rating of the HandsetTCLwweighted Terminal Coupling LossTELRTalker's Echo Loudness RatingSTMRSidetone Masking RatingQDUQuantization Distortion UnitWRSWireless Relay StationSIST ETS 300 175-8:1999



Page 13ETS 300 175-8: September 19964Configurations4.1Reference configuration4.1.1Basic configurationThe basic reference configuration for voice transmission over DECT is shown in figure 1.Acousticinterface+Volumecontrol+coderTranscoderUniformPCMto/fromair codeLineinterface+echocontrol+Volume control+coderTranscoderUniformPCMto/fromair codeUniformPCMreferencepointUniformPCMreferencepoint0]MRPERPAcousticinterfaceAirinterfaceLinePP (handset)FP (fixed part)Figure 1: Basic reference configurationThe PP and the FP are delimited by physical interfaces:-Acoustic:-from the PP towards the speaker-listener, with the Ear and Mouth Reference Points (ERPand MRP).-Air(RF):-the interface between PP and FP.-Line:-the interface from the FP towards the network.Uniform PCM reference points shall be introduced in both the PP and the FP to materialize the limits of thetransmission segment which is affected by the air interface coding scheme. This allows the transmissionrequirements to be specified independently from the coding at the air interface. The various transcodingalgorithms are level-transparent, i.e. with an encoder and decoder connected in tandem, the "levels" of thedigital signals at the uniform PCM input of the encoder and output from the decoder are identical. In aparticular implementation, the reference points may be embedded within an IC, and thus will not physicallyaccessible.SIST ETS 300 175-8:1999



Page 14ETS 300 175-8: September 1996Each of the three sections thus delimited deals with distinct functions:a)the PP electro-acoustic section (between acoustic interface and PP uniform PCM reference point)which includes the acoustic interface, the volume control and the analogue to digital conversion;b)the air-code section (between PP and FP uniform PCM reference points) considers the transcodingbetween uniform PCM and the air-code, as well as the transmission over the air interface;c)the FP line interface section (between FP uniform PCM reference point and line interface) comprisesthe interface to the line, digital or analogue, and the FP voice processing, e.g. echo control.Typically, the transmission features shall conform to ETS 300 085 [19] for the PP electro-acoustic section,and the line interface section in the case of digital interface. In the case of analogue interface, the lineinterface section realises the adaptation to ETS 300 001 [20] and to national standards.4.1.2Portable Part (PP)4.1.2.1Functional organizationFigure 2 represents the basic functional organization of a PP from the voice transmission point of view:Figure 2: PP functional organizationThe various functions represented in figure 2 are:a)the electro-acoustic function, which performs the interface to the transducers and the volumecontrol. The Handset Loudness Ratings (SLRH) and (RLRH) are defined between the acousticinterface and the uniform PCM reference point;b)the analogue to digital and digital to analogue coding to the uniform PCM reference point;c)the transcoder between uniform PCM and air-code.SIST ETS 300 175-8:1999



Page 15ETS 300 175-8: September 19964.1.2.2Volume controlThe volume control facility is optional, and can be implemented in a number of different ways:1)in the simplest implementation, it affects only the receiving level and is under the manual control ofthe PP user;2)the volume adjustment may also be adaptive, e.g. taking into account the average level of ambientnoise at the MRP;3)the volume control may affect both receiving and sending levels in opposite directions. This has theadvantage of reducing the effect on the terminal coupling loss. Such an implementation would fit anoisy environment, as the need for an increased receiving volume is likely to come from a loudambient noise, and it is then combined with a loud speech level.4.1.3Fixed Part (FP)4.1.3.1Digital interfaceFigure 3 shows the functional organization of a FP with a digital interface:Figure 3: FP functional organizationThe various functions represented in figure 3 are:a)a transcoder between air-code and uniform PCM;b)an echo control function which processes echoes coming back from both the handset and thenetwork. It provides additional losses that compensate for the increased length of the echo path dueto the DECT transmission delay over the air interface;c)a transcoder from uniform PCM to A-law PCM towards the line interface.SIST ETS 300 175-8:1999



Page 16ETS 300 175-8: September 19964.1.3.2Analogue interfaceThe organization of a FP with an analogue interface is shown in figure 4
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Digital Enhanced Cordless Telecommunications (DECT); Common Interface (CI); Part 8:
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SIST ETS 300 175-8:1999
EUROPEAN ETS 300 175-8
TELECOMMUNICATION September 1996
STANDARD Second Edition
Source: ETSI TC-RES Reference: RE/RES-03027-8
ICS: 33.060, 33.060.50
Key words: DECT, radio
Radio Equipment and Systems (RES);
Digital Enhanced Cordless Telecommunications (DECT);
Common Interface (CI);
Part 8: Speech coding and transmission
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
Tel.: [phone] - Fax: [phone]
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1996. All rights reserved.

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ETS 300 175-8: September 1996
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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ETS 300 175-8: September 1996
Contents
Foreword .7
1 Scope.9
2 Normative references.9
3 Definitions and abbreviations .11
3.1 Definitions.11
3.2 Abbreviations .12
4 Configurations .13
4.1 Reference configuration .13
4.1.1 Basic configuration.13
4.1.2 Portable Part (PP).14
4.1.2.1 Functional organization .14
4.1.2.2 Volume control.15
4.1.3 Fixed Part (FP).15
4.1.3.1 Digital interface.15
4.1.3.2 Analogue interface .16
4.1.3.3 FP adaptive volume control.16
4.2 Test configurations .16
5 Encoding.17
5.1 32 kbit/s full term (ADPCM).17
5.1.1 Algorithm .17
5.1.2 Bit sequence .17
5.2 Other codings .17
6 Transmission aspects .17
6.1 Relative level.17
6.2 Acoustic reference level.17
6.3 Volume control .17
7 Speech performance characteristics .18
7.1 PP frequency responses .18
7.1.1 Sending .18
7.1.2 Receiving.18
7.2 PP sending and receiving loudness ratings.18
7.2.1 Nominal values .18
7.2.2 User-controlled volume control in PP .19
7.2.3 PP adaptive volume control .19
7.2.4 FP adaptive volume control.20
7.3 Sidetone.20
7.3.1 Talker sidetone.20
7.3.2 Listener sidetone.20
7.4 Terminal coupling loss.21
7.4.1 Weighted Terminal Coupling Loss (TLCw) .21
7.4.1.1 PP for the 3,1 kHz service (PSTN or ISDN).21
7.4.1.2 FP with 4-wire interface.21
7.4.1.3 FP with analogue 2-wire interface .22
7.4.1.4 PP for unrestricted 64 kbit/s service .22
7.4.2 Stability loss.22
7.4.2.1 Requirement.22
7.4.2.2 Test conditions .22

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7.4.2.3 Fixed geometry PP.22
7.4.2.4 Variable geometry PP .22
7.5 Distortion .23
7.5.1 Sending.23
7.5.2 Receiving .23
7.5.3 Sidetone .23
7.5.4 Recommended value for network planning .23
7.6 Out of band signals.23
7.6.1 Sending (discrimination against out of band input signals).23
7.6.2 Receiving (spurious out of band signals) .23
7.7 Noise.24
7.7.1 Sending.24
7.7.2 Narrow-band noise.24
7.7.3 Receiving .24
7.7.4 Level of sampling frequency (receiving) .24
7.8 Acoustic shock .24
7.8.1 Continuous signal.24
7.8.2 Peak signal .24
7.9 Delay.24
7.9.1 DECT network.24
7.9.2 PP.24
7.9.3 FP.24
7.10 Network echo control .25
7.11 PP ambient noise rejection .25
8 Additional features.26
8.1 Loudspeaking and hand-free facilities.26
8.2 Tandem with mobile radio network.26
8.2.1 Tandem with GSM.26
8.2.1.1 Network echo control.26
8.2.1.2 Terminal coupling loss .26
8.2.1.3 The GSM mobile transmitter operates in continuous mode .26
8.2.1.4 The GSM mobile transmitter operates in discontinuous
mode, DTX.26
8.3 DECT connected to the GSM fixed network.27
8.3.1 Network echo control .27
8.3.2 Terminal coupling loss.27
8.4 Wireless Relay Stations (WRS) .27
8.4.1 Modified FP network echo control requirements for implementation of 2
and 3 CRFP links in cascade .28
Annex A (informative): Description of "reference" echo control devices.29
A.1 Handset echo .29
A.1.1 Overview .29
A.1.1.1 Connection to the PSTN/ISDN.29
A.1.1.1.1 Local and national calls.29
A.1.1.1.2 Long distance connections with echo control devices in the
PSTN/ISDN, e.g. calls via satellites .29
A.1.1.2 Connection to the GSM network .30
A.1.2 Implementation of the FP echo control function subclause 7.4.1.2 b.30
A.1.2.1 Suppression threshold.30
A.1.2.2 Static characteristics of activation control .31
A.1.2.3 Dynamic characteristics of activation control .31
A.2 Network echo.31
A.2.1 Soft suppressor implementation of requirement 2 of subclause 7.10.32
A.2.1.1 Static characteristics.32
A.2.1.2 Dynamic characteristics.32
A.2.2 Additional echo control for a 2-wire interface of requirement 1 of subclause 7.10.32

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A.2.3 Echo canceller used for both requirements 1 and 2 .33
Annex B (informative): Local loop application .34
B.1 DECT tethered local loop replacement with 2-wire PP end system.34
B.1.1 TCLw requirements .34
B.1.2 Network echo.35
B.2 Quantization distortion considerations.35
Annex C (informative): GSM Discontinuous Transmission (DTX), and Voice Activity Detection (VAD) .36
Annex D (informative): Speech levels in relation to ambient room noise and examples of adaptive
volume control settings .37
Annex E (informative): Bibliography.38
History .39

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Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the Radio
Equipment and Systems (RES) Technical Committee of the European Telecommunications Standards
Institute (ETSI).
This ETS forms part 8 of a series of 9 laying down the arrangements for the Digital Enhanced Cordless
Telecommunications (DECT) Common Interface (CI).
Part 1: "Overview".
Part 2 "Physical layer (PHL)".
Part 3 "Medium Access Control (MAC) layer".
Part 4 "Data Link Control (DLC) layer".
Part 5: "Network (NWK) layer".
Part 6: "Identities and addressing".
Part 7: "Security features".
Part 8: "Speech coding and transmission".
Part 9: "Public Access Profile (PAP)".
Further details of the DECT system may be found in ETR 015, ETR 043, and ETR 056 (see annex E).
Transposition dates
Date of adoption of this ETS: 6 September 1996
Date of latest announcement of this ETS (doa): 31 December 1996
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 June 1997
Date of withdrawal of any conflicting National Standard (dow): 30 June 1997

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1 Scope
This second edition European Telecommunication Standard (ETS) is part of the Digital Enhanced Cordless
Telecommunications (DECT) Common Interface (CI) and specifies the speech coding and transmission
requirements.
In order to ensure satisfactory interworking of different portable and fixed units, it is necessary to specify
the transmission performance of the analogue information over the digital link. This requires not only use of
a common speech algorithm, but also standardization of frequency responses, reference speech levels (or
loudness) at the air interface and various other parameters.
This ETS applies to DECT equipment which includes all the necessary functions to provide real-time
two-way speech conversation. A 3,1 kHz telephony teleservice conveyed over a DECT link (including Fixed
Part (FP) and Portable Part (PP)) which is capable of being connected (directly or indirectly) to the public
network access point has to comply with the requirements in this ETS.
Tethered fixed point local loop applications are not required to comply with the requirements of this part.
The speech performance characteristics defined in this ETS typically conform to ETS 300 085 [19], which
specifies the overall performance between the handset acoustic interface and a 64 kbit/s A-law Pulse
Code Modulated (PCM) digital network interface. The deviations from ETS 300 085 [19] are mainly due to
the consequences of non-PCM coding and transmission delay.
The additional features described in clause 8 are those which are not included in ETS 300 085 [19], but
which are likely to occur in a DECT system: analogue interface, loudspeaking and hand-free facilities,
tandeming with a mobile radio network. Headsets are not covered by the present specifications.
For the DECT systems which connect to the Public Switched Telephone Network (PSTN) via an analogue
interface, this ETS includes the basics on which the national specifications can be built, referring to
ETS 300 001 [20] (which specifies the connection of terminal equipments to the PSTN via a 2-wire
analogue interface) and the appropriate national standard.
ETSI/STC TM5 has prepared a technical report, ETR 041, to be used as a guide for network planning.
A summary of the control and the use of the DECT echo control functions, to guide on need for options to
manufacturers and installers, is found in the supplementary services clause of ETR 056.
Information concerning test methods can be found in I-ETS 300 176 [9]. The test methods take into
account that DECT is a digital system.
2 Normative references
This ETS incorporates, by dated or undated reference, provisions from other publications. These normative
references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this ETS
only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies.
[1] ETS 300 175-1 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 1:
Overview".
[2] ETS 300 175-2 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 2: Physical
Layer (PHL)".
[3] ETS 300 175-3 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 3: Medium
Access Control (MAC) layer".

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[4] ETS 300 175-4 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 4: Data
Link Control (DLC) layer".
[5] ETS 300 175-5 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 5: Network
(NWK) layer".
[6] ETS 300 175-6 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 6: Identities
and addressing".
[7] ETS 300 175-7 (1996): "Radio Equipment and Systems (RES); Digital European
Cordless Telecommunications (DECT); Common Interface (CI); Part 7: Security
features".
[8] ETS 300 444: "Radio Equipment and Systems (RES); Digital European Cordless
Telecommunications (DECT): Generic Access Profile (GAP)".
[9] I-ETS 300 176: "Radio Systems and Equipment (RES); Digital European
Cordless Telecommunications (DECT) Approval test specification".
[10] CCITT Recommendation G.101 (1988): "The transmission plan".
[11] CCITT Recommendation G.131 (1988): "Stability and echo".
[12] CCITT Recommendation G.164 (1988): "Echo suppressors".
[13] CCITT Recommendation G.165 (1988): "Echo cancellers".
[14] CCITT Recommendation G.701 (1988): "Vocabulary of digital transmission and
multiplexing, and pulse code modulation (PCM) terms".
[15] CCITT Recommendation G.726 (1991): "40, 32, 24, 16 kbit/s adaptive
differential pulse code modulation (ADPCM)".
[16] CCITT Recommendation I.241 (1988): "Teleservices supported by an ISDN".
[17] CCITT Recommendation P.10 (1988): "Vocabulary of terms on telephone
transmission quality and telephone sets".
[18] CCITT Recommendation P.34 (1988): "Transmission characteristics of
hands-free telephones".
[19] ETS 300 085: "Integrated Services Digital Network (ISDN): 3,1 kHz telephony
teleservice; Attachment requirements for handset terminals" (text relevant for
NET 33).
[20] ETS 300 001: "Attachments to Public Switched Telephone Network (PSTN);
General technical requirements for equipment connected to an analogue
subscriber interface in the PSTN" (Candidate NET 4).
[21] CCITT Recommendation G.113 (1988): "Transmission impairments".
[22] CCITT Recommendation G.111 (1988): "Loudness ratings (LRs) in an
international connection".
[23] ETS 300 540: "Digital cellular telecommunications system (Phase 2);
Transmission planning aspects of the speech service in the GSM Public Land
Mobile Network (PLMN) system (GSM 03.50)".

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3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
Central Control Fixed Part (CCFP): See ETS 300 175-1 [1].
Cordless Radio Fixed Part (CRFP): See ETS 300 175-1 [1].
DECT Network (DNW): See ETS 300 175-1 [1].
double duplex bearer : See ETS 300 175-1 [1].
End System (ES): See ETS 300 175-1 [1].
fixed geometry Portable Part (PP): A PP in which the electro-acoustic transducers and their associated
acoustic components are held in fixed relative positions and/or orientations during all on-line conditions and
test conditions of the PP.
Fixed Part (DECT Fixed Part) (FP): See ETS 300 175-1 [1].
Fixed radio Termination (FT): See ETS 300 175-1 [1].
Generic Access Profile (GAP): A standard in addition to the DECT CI that ensures interoperability
between FPs and PPs from different manufacturers.
handset echo: The echo, perceptible by the far-end user, resulting from the coupling between the
receiving and sending directions of the handset, mostly due to acoustic coupling between transducers. It is
particularly objectionable in communications including a satellite and an echo canceller, as the DECT
handset echo may be out of range of the echo canceller.
network (telecommunication network): See ETS 300 175-1 [1].
network echo: The echo, perceptible by the DECT user, resulting from reflections in the network. It is
mostly due to hybrid impairments at both ends of the communication.
operator (DECT operator): See ETS 300 175-1 [1].
Portable Handset (PHS): See ETS 300 175-1 [1].
Portable Part (DECT Portable Part) (PP): See ETS 300 175-1 [1].
Portable radio Termination (PT): See ETS 300 175-1 [1].
public: See ETS 300 175-1 [1].
public access service: See ETS 300 175-1 [1].
Radio Fixed Part (RFP): See ETS 300 175-1 [1].
Repeater Part (REP) : See ETS 300 175-1 [1].
service provider (telecommunications service provider): See ETS 300 175-1 [1].
telephony service: See CCITT Recommendation I.241 [16].
user (of a telecommunication network): See ETS 300 175-1 [1].

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variable geometry PP: A PP that allows the position and/or orientation of its electro-acoustic transducers
and their associated acoustic components to be changed during all on-line conditions of the PP.
Wireless Relay Station (WRS): See ETS 300 175-1 [1].
3.2 Abbreviations
For the purposes of this ETS, relevant definitions and abbreviations in CCITT Recommendations P.10 [17]
and G.701 [14] apply. In addition the following abbreviations apply:
ADPCM Adaptive Differential Pulse Code Modulation
ARL Acoustic Reference Level
CCFP Central Control Fixed Part
CI Common Interface
CFRP Cordless Radio Fixed Part
CLRR Circuit Loudness Rating, Receiving
CLRS Circuit Loudness Rating, Sending
CODEC Coder-Decoder
CRFP Cordless Radio Fixed Part
CSPDN Circuit Switched Public Data Network
dBm dB relative to 1 milliwatt
dBm0 The absolute power level in decibels referred to a point of zero relative level
dBr The relative power level in decibels
DECT Digital Enhanced Cordless Telecommunications
DNW DECT Network
ERP Ear Reference Point
ES End System
FP Fixed Part
FT Fixed radio Termination
GAP Generic Access Profile
ISDN Integrated Services Digital Network
LE Local Echo
LSTR Listener Sidetone Rating
MRP Mouth Reference Point
NLP Non-Linear Processor
NWK Network
OLR Overall Loudness Rating
P(A)BX Private (Automatic) Branch Exchange
PAP Public Access Profile
PHS Portable Handset
PP Portable Part
PSPDN Packet Switched Public Data Network
PSTN Public Switched Telephone Network
PT Portable radio Termination
PTN Private Telecommunication Network
ReFP Reference Fixed Part
RePP Reference Portable Part
REP REpeater Part
RFP Radio Fixed Part
RLR Receiving Loudness Rating of the Handset
H
SLR Sending Loudness Rating of the Handset
H
TCLw weighted Terminal Coupling Loss
TELR Talker's Echo Loudness Rating
STMR Sidetone Masking Rating
QDU Quantization Distortion Unit
WRS Wireless Relay Station

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4 Configurations
4.1 Reference configuration
4.1.1 Basic configuration
The basic reference configuration for voice transmission over DECT is shown in figure 1.
PP (handset) FP (fixe d part)
Acoustic Air
in te rfa ce in te rfa ce L in e
Lin e
MR P
Acoustic in te rfa ce
Transcoder Transcoder
0 interface +
+ ec ho
Uniform Uniform
Volume control
PCM PC M
control +
to/from to/from
+ V o lu m e control
air code air code
coder +
]
co der
ERP
Uniform Uniform
PCM PCM
re feren ce reference
point point
Figure 1: Basic reference configuration
The PP and the FP are delimited by physical interfaces:
- Acoustic:
- from the PP towards the speaker-listener, with the Ear and Mouth Reference Points (ERP
and MRP).
- Air(RF):
- the interface between PP and FP.
- Line:
- the interface from the FP towards the network.
Uniform PCM reference points shall be introduced in both the PP and the FP to materialize the limits of the
transmission segment which is affected by the air interface coding scheme. This allows the transmission
requirements to be specified independently from the coding at the air interface. The various transcoding
algorithms are level-transparent, i.e. with an encoder and decoder connected in tandem, the "levels" of the
digital signals at the uniform PCM input of the encoder and output from the decoder are identical. In a
particular implementation, the reference points may be embedded within an IC, and thus will not physically
accessible.

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Each of the three sections thus delimited deals with distinct functions:
a) the PP electro-acoustic section (between acoustic interface and PP uniform PCM reference point)
which includes the acoustic interface, the volume control and the analogue to digital conversion;
b) the air-code section (between PP and FP uniform PCM reference points) considers the transcoding
between uniform PCM and the air-code, as well as the transmission over the air interface;
c) the FP line interface section (between FP uniform PCM reference point and line interface) comprises
the interface to the line, digital or analogue, and the FP voice processing, e.g. echo control.
Typically, the transmission features shall conform to ETS 300 085 [19] for the PP electro-acoustic section,
and the line interface section in the case of digital interface. In the case of analogue interface, the line
interface section realises the adaptation to ETS 300 001 [20] and to national standards.
4.1.2 Portable Part (PP)
4.1.2.1 Functional organization
Figure 2 represents the basic functional organization of a PP from the voice transmission point of view:
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