ETSI ETS 300 175-8 ed.1 (1992-10)

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

DE/RES-03002-8

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

General Information

• Status: Published
• Publication Date: 26-Oct-1992
• Technical Committee: RES 3 - DECT
• Current Stage: 13 - TB decision to make document historical
• Completion Date: 28-Sep-2001
• Mandate: T-176
• Ref Project: SIST ETS 300 175-8 E1:2005 - Radio Equipment and Systems (RES); 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.QHRadio Equipment and Systems (RES); 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 Edition 1SIST ETS 300 175-8 E1:2005en01-julij-2005SIST ETS 300 175-8 E1:2005SLOVENSKI
STANDARD
EUROPEANETS 300 175-8TELECOMMUNICATIONOctober 1992STANDARDSource: ETSI TC-RESReference: DE/RES-3001-8ICS:33.060Key words:DECTRadio Equipment and Systems (RES);Digital European Cordless Telecommunications (DECT)Common interfacePart 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 1992. All rights reserved.SIST ETS 300 175-8 E1:2005New presentation - see History box

Page 2ETS 300 175-8: October 1992Whilst 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 E1:2005

Page 3ETS 300 175-8: October 1992ContentsForeword.71Scope.92Normative references.93Definitions and abbreviations.113.1Definitions.113.2Abbreviations.134Configurations.154.1Reference configuration.154.1.1Basic configuration.154.1.2Portable Part (PP).164.1.2.1Functional organisation.164.1.2.2Volume control.164.1.3Fixed Part (FP).174.1.3.1Digital interface.174.1.3.2Analogue interface.174.1.3.3FP adaptive volume control.184.2Test configurations.185Encoding.185.132 Kbit/s full term (ADPCM).185.1.1Algorithm.185.1.2Bit sequence.185.2Other codings.186Transmission aspects.186.1Relative level.186.2Acoustic reference level.186.3Volume control.187Speech performance characteristics.197.1PP frequency responses.197.1.1Sending.197.1.2Receiving.197.2PP sending and receiving loudness ratings.197.2.1Nominal values.197.2.2User-controlled volume control in PP.197.2.3PP adaptive volume control.207.2.4FP adaptive volume control.207.3Sidetone.207.3.1Talker sidetone.207.3.2Listener sidetone.217.4Terminal 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 E1:2005

Page 4ETS 300 175-8: October 19927.4.2.3Fixed geometry PP.227.4.2.4Variable geometry PP.237.5Distortion.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).247.7Noise.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.257.9.3FP.257.10Network 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.27Annex A (informative): Description of "reference" echo control devices.28A.1Handset echo.28A.1.1Overview.28A.1.1.1Connection to the PSTN/ISDN.28A.1.1.1.1Local and national calls.28A.1.1.1.2Long distance connections with echo control devices in thePSTN/ISDN, e.g. calls via satellites.28A.1.1.2Connection to the GSM network.29A.1.2Implementation of the FP echo control function subclause 7.4.1.2 b).29A.1.2.1Suppression threshold.29A.1.2.2Static characteristics of activation control.30A.1.2.3Dynamic characteristics of activation control.30A.2Network echo.30A.2.1Soft suppressor implementation of requirement 2 of subclause 7.10.31A.2.1.1Static characteristics.31A.2.1.2Dynamic characteristics.31A.2.2Additional echo control for a 2-wire interface of requirement 1 of subclause 7.10.31A.2.3Echo canceller used for both requirements 1 and 2.32SIST ETS 300 175-8 E1:2005

Page 5ETS 300 175-8: October 1992Annex B (informative):Local loop application.33B.1DECT tethered local loop replacement with 2-wire PP end system.33B.1.1TCLw requirements.33B.1.2Network echo.34B.2Quantisation distortion considerations.34Annex C (informative):GSM Discontinuous Transmission (DTX), and Voice Activity Detection (VAD).35Annex D (informative):Speech levels in relation to ambient room noise and examples of adaptivevolume control settings.36Annex E (informative):Public Access Profile (PAP): mandatory requirements regarding speechtransmission.37E.1General.37E.2User controlled volume control.37E.3PP ambient noise rejection capability feature.37History.38SIST ETS 300 175-8 E1:2005

Page 6ETS 300 175-8: October 1992Blank pageSIST ETS 300 175-8 E1:2005

Page 7ETS 300 175-8: October 1992ForewordThis European Telecommunication Standard (ETS) has been produced by the Radio Equipment andSystems (RES) Technical Committee of the European Telecommunications Standards Institute (ETSI), andwas adopted, having passed the ETSI standards approval procedure (Public Enquiry 23: 1991-09-02 to1991-12-27, Vote 22: 1992-05-25 to 1992-07-17).Annexes A, B, C and D to this ETS are informative.Further details of the DECT system may be found in the ETSI Technical Report ETR 015 [16] and ETR043 [15], and also in ETSI Draft Technical Report, "Digital European Cordless Telecommunications SystemDescription Document" [17].SIST ETS 300 175-8 E1:2005

Page 8ETS 300 175-8: October 1992Blank pageSIST ETS 300 175-8 E1:2005

Page 9ETS 300 175-8: October 19921ScopeThis part of the Digital European Cordless Telecommunications (DECT) Common Interface specifies thespeech coding and transmission requirements. It is Part 8 of a series of 9.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 standardisation of frequency responses, reference speech levels (orloudness) at the air interface and various other parameters.This part 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 FP andPP) which is capable of being connected (directly or indirectly) to the public network access point shallcomply with the requirements in this part.Tethered fixed point local loop applications are not required to comply with the requirements of this part.The speech performance characteristics defined in this document typically conform to ETS 300 085 [32],which specifies the overall performance between the handset acoustic interface and a 64 kbps A-law PulseCode Modulated (PCM) digital network interface. The deviations from ETS 300 085 [32] 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 [32], 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 document includes the basics on which the national specifications can be built, referring toprETS 300 001 [33] (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 "Transmission Multiplexing (TM) DigitalEuropean Cordless Telecommunications (DECT); Transmission aspects 3,1 kHz telephony, interworkingwith other networks" [20], 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 chapter of the technical report "DigitalEuropean Cordless Telecommunications System description document" [17].Information concerning test methods can be found in I-ETS 300 176 [12]. The test methods take intoaccount that DECT is a digital system.2Normative referencesThis European Telecommunication Standard (ETS) incorporates, by dated or undated reference,provisions from other publications. These normative references are cited at the appropriate places in thetext and the publications are listed hereafter. For dated references, subsequent amendments to orrevisions of any of these publications apply to this ETS only when incorporated in it by amendment orrevision. For undated references the latest edition of the publication referred to applies.[1]ETS 300 175-1: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 1: Overview".[2]ETS 300 175-2: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 2: Physical layer".[3]ETS 300 175-3: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 3: Mediumaccess control layer".SIST ETS 300 175-8 E1:2005

Page 10ETS 300 175-8: October 1992[4]ETS 300 175-4: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 4: Data linkcontrol layer".[5]ETS 300 175-5: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 5: Network layer".[6]ETS 300 175-6: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 6: Identities andaddressing".[7]ETS 300 175-7: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 7: Securityfeatures".[8]ETS 300 175-8: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 8: Speech codingand transmission".[9]ETS 300 175-9: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Common interface Part 9: Public accessprofile".[10]Reserved.[11]Reserved.[12]I-ETS 300 176: "Radio Systems and Equipment (RES); Digital EuropeanCordless Telecommunications (DECT) Approval test specification".[13]Reserved for future ETS version of [12].[14]CEPT Recommendation T/SGT SF2 (89) 6/0 : "Draft Recommendation T/SFServices and Facilities of Digital European Cordless Telecommunications".[15]ETR 043: "Radio Systems and Equipment (RES); Digital European CordlessTelecommunications (DECT) Common interface Services and facilitiesrequirements specification".[16]ETR 015: "Digital European Cordless Telecommunications Referencedocument".[17]Draft ETSI Technical Report: "Digital European Cordless TelecommunicationsSystem description document".[18]ETR 042: "Radio Systems and Equipment (RES); Digital European CordlessTelecommunications (DECT); A guide to DECT features that influence the trafficcapacity and the maintenance of high radio link transmission quality, including theresults of simulations".[19]Reserved for future DECT document.[20]ETR 041: "Transmission Multiplexing (TM) Digital European CordlessTelecommunications (DECT) Transmission aspects 3,1 kHz telephony,interworking with other networks".[21]CCITT Recommendation G.101 (1988): "The Transmission Plan".[22]CCITT Recommendation G.131 (1988): "Stability and echo".SIST ETS 300 175-8 E1:2005

Page 11ETS 300 175-8: October 1992[23]CCITT Recommendation G.164 (1988): "Echo Suppressors".[24]CCITT Recommendation G.165 (1988): "Echo Cancellers".[25]CCITT Recommendation G.173 (1988): "Transmission planning aspects of thespeech service in digital public land mobile networks".[26]CCITT Recommendation G.701 (1988): "Vocabulary of digital transmission andmultiplexing, and pulse code modulation".[27]CCITT Recommendation G.711 (1988): "Pulse code modulation (PCM) of voicefrequencies".[28]CCITT Recommendation G.721 (1988): "32 kbit/s adaptive differential pulsecode modulation (ADPCM)".[29]CCITT Recommendation I.241 (1988): "Teleservices supported by an ISDN".[30]CCITT Recommendation P.10 (1988): "Vocabulary of terms on telephonetransmission quality and telephone sets".[31]CCITT Recommendation P.34 (1988): "Transmission characteristics of hands-free telephones".[32]ETS 300 085: "Integrated Services Digital Network (ISDN): 3,1 kHz telephonyteleservice; Attachment requirements for handset terminals" (text relevant forNET 33).[33]prETS 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).[34]CCITT Recommendation G.113 (1988): "Transmission Impairments".[35]CCITT Recommendation G.111 (1988): "General recommendations on thetransmission quality for an entire international telephone connection".[36]GSM Recommendation 03.50: "Transmission Planning Aspects of the SpeechService in the GSM PLMN System (Version 3.1.0)".3Definitions and abbreviations3.1DefinitionsFor the purpose of this ETS, the following definitions which are listed in alphabitical order, apply:Central Control Fixed Part (CCFP): a physical grouping that contains the central elements of a fixed part.A fixed part shall contain a maximum of one CCFP.NOTE:A CCFP controls one or more RFPs.DECT NetWork (DNW): a network that uses the DECT air interface to interconnect a local network (LNW)to one or more portable applications. The logical boundaries of the DECT network are defined to be at thetop of the DECT network layer.NOTE:A DECT NetWork (DNW) is a logical grouping that contains one or more Fixed radioTerminations (FTs) plus their associated Portable radio Termination (PTs). Theboundaries of the DECT network are not physical boundaries.SIST ETS 300 175-8 E1:2005

Page 12ETS 300 175-8: October 1992End System (ES): a logical grouping that contains application processes and supports telecommunicationservices.NOTE:From the OSI point of view, end systems are considered as sources and sinks ofinformation.Fixed geometry (PP): a Portable Part (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): a physical grouping that contains all of the elements in the DECTnetwork between the Local NetWork (LNW) and the DECT air interface.NOTE:A DECT fixed part contains the logical elements of at least one Fixed radio Termination(FT), plus additional implementation specific elements.Fixed part Termination (FT): a logical group of functions that contains all of the DECT processes andprocedures on the fixed side of the DECT air interface.NOTE:A Fixed radio Termination (FT) only includes elements that are defined in the DECT CIstandard. This includes radio transmission elements (layer 1) together with a selectionof layer 2 and layer 3 elements.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): all the means of providing telecommunication services betweena number of locations where the services are accessed via equipment attached to the network.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: the individual or entity who or which is responsible for operation of one or more DECT fixedparts.NOTE:The term does not imply any legal or regulatory conditions, nor does it imply anyaspects of ownership.Portable HandSet (PHS): a single physical grouping that contains all of the portable elements that areneeded to provide a teleservice to the user.NOTE:Portable HandSet (PHS) is a subset of all possible Portable Parts (PPs). This subsetincludes all physical groupings that combine one Portable radio Termination (PT) plus atleast one portable application in a single physical box.Portable Part (DECT Portable Part) (PP): a physical grouping that contains all elements between theuser and the DECT air interface. Portable Part (PP) is a generic term that may describe one or severalphysical pieces.NOTE:A DECT Portable Part (PP) is logically divided into one Portable Termination (PT) plusone or more portable applications.Portable radio Termination (PT): a logical group of functions that contains all of the DECT processesand procedures on the portable side of the DECT air interface.NOTE:A Portable radio Termination (PT) only includes elements that are defined in the DECTCI standard. This includes radio transmission elements (layer 1) together with aselection of layer 2 and layer 3 elements.SIST ETS 300 175-8 E1:2005

Page 13ETS 300 175-8: October 1992Public: an attribute indicating that the application of the so qualified term, e.g. a network, a equipment, aservice, is offered to or is in the interest of the general public.NOTE:The term does not include any legal or regulatory aspects, nor does it indicate anyaspects of ownership.Public Access Profile (PAP): a defined part of the DECT Common Interface standard (DECT CI) thatensures interoperability between Fixed Parts (FPs) and Portable Parts (PPs) for public access services.Public access service: a service that provides access to a public network for the general public.NOTE:The term does not imply any legal or regulatory aspect, nor does it imply any aspectsof ownership.Radio Fixed Part (RFP): one physical sub-group of a Fixed Part (FP) that contains all the Radio EndPoints (REPs) (one or more) that are connected to a single antenna system.Service provider (telecommunications service provider): the individual or entity who or whichinterfaces to the customer in providing telecommunications service.NOTE 1:The term does not imply any legal or regulatory conditions, nor does it indicate whetherpublic service or private service is provided.NOTE 2:The term service provider is also used with a different meaning in the ISO/OSI layeredmodel.Telephony service: a definition of telephony service is found in CCITT Recommendation I.241 [29].User (of a telecommunication network): a person or machine delegated by a subscriber (by acustomer) to use the services and/or facilities of a telecommunication network.Variable geometry (PP): a PP that allows the position and/or orientation of its electro-acoustictransducers and their associated acoustic components to be changed during all on-line conditions of thePP.3.2AbbreviationsRelevant definitions and abbreviations in CCITT Recommendations P.10 [30] and G.701 [26] apply.ADPCMAdaptive Differential Pulse Code ModulationARLAcoustic Reference LevelCCFPCentral Control Fixed Part. See definitionsCCITT(The) International Telegraph and Telephone Consultative CommitteeCICommon Interface (standard)CLRRCircuit Loudness Rating, ReceivingCLRSCircuit Loudness Rating, SendingCODECCOder-DECoderCSPDNCircuit Switched Public Data NetworkdBmdB relative to 1 milliwattdBm0The absolute power level in decibels referred to a point of zero relative levelSIST ETS 300 175-8 E1:2005

Page 14ETS 300 175-8: October 1992dBrThe relative power level in decibelsDECTDigital European Cordless TelecommunicationsERPEar Reference PointESEnd SystemFPFixed Part. See definitionsFTFixed radio Termination. See definitionsISDNIntegrated Services Digital NetworkLELocal EchoLSTRListener Sidetone RatingMRPMouth Reference PointNLPNon-Linear ProcessorOLROverall Loudness RatingP(A)BXPrivate (Automatic) Branch eXchangePPPortable Part. See definitionsPSPDNPacket Switched Public Data NetworkPSTNPublic Switched Telephone NetworkPTPortable radio Termination. See definitionsPTNPrivate Telecommunication NetworkReFPReference Fixed PartRePPReference Portable PartRFPRadio Fixed Part. See definitionsRLRHReceiving Loudness Rating of the HandsetSLRHSending Loudness Rating of the HandsetTCLwweighted Terminal Coupling LossTELRTalker's Echo Loudness RatingSTMRSidetone Masking RatingQDUQuantisation Distortion UnitSIST ETS 300 175-8 E1:2005

Page 15ETS 300 175-8: October 19924Configurations4.1Reference configuration4.1.1Basic configurationThe basic reference configuration for voice transmission over DECT is shown in figure 1.
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pointFigure 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 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 materialise 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, those reference points may be embedded within an IC, and thus are notphysically accessible.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)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 [32] 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 prETS 300 001 [33] and to national standards.SIST ETS 300 175-8 E1:2005

Page 16ETS 300 175-8: October 19924.1.2Portable Part (PP)4.1.2.1Functional organisationFigure 2 represents the basic functional organisation of a PP from the voice transmission point of view:
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³Figure 2: PP functional organisationThe 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.4.1.2.2Volume 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.SIST ETS 300 175-8 E1:2005

Page 17ETS 300 175-8: October 19924.1.3Fixed Part (FP)4.1.3.1Digital interfaceFigure 3 shows the functional organisation of a FP with a digital interface:
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³Figure 3: FP functional organisationThe 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.4.1.3.2Analogue interfaceThe organisation of a FP with an analogue interface is shown in figure 4.
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³<ÄÄÄÄÄÄÄÄÄÄÄÄCLRRÄÄÄÄÄÄÄÄÄÄÄÄÄÄijFigure 4: FP with an analogue interfaceThe various functions represented in figure 4 are:a)the line interface comprises the digital to analogue coder-decoder and the adaptation to the line, thatcan be either 2- or 4-wire. The Circuit Loudness Ratings (CLRR and CLRS) are defined betweenuniform PCM reference point and the line interface;b)in the case of a 2-wire line, the network echo controller deals with the local hybrid echo, which issuperimposed on the network echo in a manner similar to the digital line interface.NOTE:Due to different transmission characteristics of the 2-wire local access in Europeancountries, it is recommended that careful attention is paid to the transmissionspecification of the 2-wire FP interface, particularly in respect of transmission loss andimpedance.SIST ETS 300 175-8 E1:2005

Page 18ETS 300 175-8: October 19924.1.3.3FP adaptive volume controlAn adaptive dual volume adjustment, as described in subclause 4.1.2.2, may optionally be implementedinto the FP, for base stations where the associated PPs may be used in a noisy environment (e.g. publicaccess).4.2Test configurationsA DECT system comprises a FP and a PP. As these parts are not always purchased together, it is arequirement that either the complete system or each of the two separate parts shall be capable of beingtested (see I-ETS 300 176 [12]).5Encoding5.132 Kbit/s full term (ADPCM)5.1.1AlgorithmThe speech coding algorithm shall conform to CCITT Recommendation G.721 [28] for 32 Kbit/s AdaptiveDifferential Pulse Code Modulation (ADPCM).The A-law companding and synchronous tandem adjustment may be omitted in FPs with an analogue lineinterface and in PPs.NOTE:CCITT Recommendation G.721 [28] codecs support use of the voice channel fortelefax of group 2 and group 3. For group 3 the data speed, which is automaticallynegotiated, shall be limited to 4,8 kbps.5.1.2Bit sequenceThe ADPCM words comprised in each burst shall be transmitted in chronological order, and with the mostsignificant bit transmitted first within each word.5.2Other codingsNo other coding scheme is permitted at this time. When introducing a new coding the following speechperformance characteristics shall be reviewed: frequency response, distortion, delay and, if the latter iswidely affected, terminal coupling loss and network echo control.6Transmission aspects6.1Relative levelThe digital line interface is a 0 dBr point according to CCITT Recommendation G.101 [21]. As the variousdigital transcoding algorithms are essentially loss-less, that relative level is constant over the whole digitalpath in the PP and the FP.6.2Acoustic reference levelThe acoustic reference level is defined as the acoustic level which corresponds to a level of- 10 dBm0 at the digital interface.6.3Volume controlUnless stated otherwise, if a user-controlled volume control is provided at the PP, the requirements applyfor all positions of the volume control, and the compliance tests shall be carried out at the maximum settingof this volume control.NOTE:The testing of a PP with a dual or an adaptive volume control requires further study.SIST ETS 300 175-8 E1:2005

Page 19ETS 300 175-8: October 19927Speech performance characteristics7.1PP frequency responses7.1.1SendingThe sending sensitivity-frequency response (from MRP to the digital interface) shall be within a mask asdefined in the following table:Table 1: Sending sensitivity-frequency maskÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿³
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Page 20ETS 300 175-8: October 1992Where such volume controls are provided the RLRH and SLRH shall simultaneously meet the nominalvalues including the manufacturing tolerance for at least one setting of the volume control. This setting isdefined as the nominal setting. The RLRH and the SLRH shall not exceed the limits given in the followingtables.Table 3: Absolute limits for '"joint-acting" volume controlÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄ¿³ Volume setting ³
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³ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÙ7.2.3PP adaptive volume controlThe PP shall inform the FP if an adaptive volume control is implemented in the PP. Subclause 7.7.41 inETS 300 175-5 [5] describes how this shall be done.For further study. To follow GSM or other specification when available.7.2.4FP adaptive volume controlAn adaptive volume control, depending on the level of environmental noise at the PP, may be implementedinto the FP. The gain variation shall be symmetrical, i.e. the increase in the receiving direction shall beequal to the decrease in the sending direction.If the PP adaptive volume control feature is implemented then the FP adaptive volume control feature shallbe disabled.NOTE 1:The PP ambient noise level shall be calculated in the FP based upon the minimumambient noise rejection requirement as specified in subclause 7.11.NOTE 2:For an FP with an analogue interface, problems of saturation may occur depending onnational RLR values.See Annex D for further information.7.3Sidetone7.3.1Talker sidetoneThe sidetone path shall be implemented in the PP.The nominal value of the Sidetone Masking Rating (STMR) shall be 13 dB. There is a manufacturingtolerance of ± 5 dB. The requirement shall be met with SLRH and RLRH corrected to the nominal values ofSLRH and RLRH.NOTE:It is recommended that the sidetone level is independent of the receiving volumecontrol.SIST ETS 300 175-8 E1:2005

Page 21ETS 300 175-8: October 19927.3.2Listener sidetoneThe value of the Listener Sidetone Rating (LSTR) shall not be less than 10 dB.For PPs with declared noise rejection capability the value of the Listener Sidetone Rating (LSTR) shall notbe less than 15 dB.NOTE:The noise rejection capability option is recommended for PPs used in noisyenvironments.The requirement shall be met with RLRH corrected to the nominal value of RLRH as defined in subclause7.2.1.PPs with declared noise rejection capability option shall indicate this to the FP at call set-up by includingthis information in the <> information element. See ETS 300 175-5 [5]subclause 7.7.41.7.4Terminal coupling lossThe PP shall be suspended in free air.7.4.1Weighted Terminal Coupling Loss (TLCw)7.4.1.1PP for the 3,1 kHz service (PSTN or ISDN)For a PP that is designed to provide the 3,1 kHz service, either on ISDN or PSTN, the weighted TerminalCoupling Loss (TCLw) defined from the PP digital input to the PP digital output
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