ETSI EN 300 449 V1.2.1 (2001-07)

Access and Terminals (AT); Special quality voice bandwidth 2-wire analogue leased line (A2S); Connection characteristics and network interface presentation

REN/AT-010002

Dostop in terminali (AT) - Analogni 2-žični zakupljeni vodi z govorno pasovno širino in posebno kakovostjo (A2S) - Priključitvene značilnosti in omrežni vmesnik

General Information

• Status: Published
• Publication Date: 03-Jul-2001
• Technical Committee: AT Analogue - AT Analogue
• Current Stage: 12 - Completion
• Due Date: 06-Jul-2001
• Completion Date: 04-Jul-2001
• Mandate: T-147-2
• Ref Project: SIST EN 300 449 V1.2.1:2004 - Access and Terminals (AT); Special quality voice bandwidth 2-wire analogue leased line (A2S); Connection characteristics and network interface presentation

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Access and Terminals (AT); Special quality voice bandwidth 2-wire analogue leased line (A2S); Connection characteristics and network interface presentation33.040.50Vodi, zveze in tokokrogiLines, connections and circuitsICS:Ta slovenski standard je istoveten z:EN 300 449 Version 1.2.1SIST EN 300 449 V1.2.1:2004en01-oktober-2004SIST EN 300 449 V1.2.1:2004SLOVENSKI
STANDARD



SIST EN 300 449 V1.2.1:2004



ETSIEN300449V1.2.1(2001-07)EuropeanStandard(Telecommunicationsseries)AccessandTerminals(AT);Specialqualityvoicebandwidth2-wireanalogueleasedline(A2S);ConnectioncharacteristicsandnetworkinterfacepresentationSIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)2ReferenceREN/AT-010002KeywordsONP,leasedlineETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/88ImportantnoticeIndividualcopiesofthepresentdocumentcanbedownloadedfrom:http://www.etsi.orgThepresentdocumentmaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.Usersofthepresentdocumentshouldbeawarethatthedocumentmaybesubjecttorevisionorchangeofstatus.InformationonthecurrentstatusofthisandotherETSIdocumentsisavailableathttp://www.etsi.org/tb/status/Ifyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]opartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2001.Allrightsreserved.SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)3ContentsIntellectualPropertyRights.5Foreword.5Introduction.51Scope.62References.63Definitions,symbolsandabbreviations.73.1Definitions.73.2Symbolsandabbreviations.74Requirements.84.1Connectioncharacteristics.84.1.1Tabulationofconnectioncharacteristics.84.1.2Overallloss.94.1.3Loss/frequencydistortion.94.1.4Transmissionsignals.104.1.4.1Maximummeaninputpower.104.1.4.2Maximuminstantaneouspower.104.1.4.3Maximumpowerina10Hzbandwidth.104.1.4.4Maximuminputpoweroutsidethevoiceband.104.1.5Transmissiondelay.104.1.6Groupdelaydistortion.114.1.7Variationofoveralllosswithtime.124.1.7.1Amplitudehits.124.1.7.2Othervariations.124.1.8Randomcircuitnoise.124.1.9Impulsivenoise.134.1.10Phasejitter.134.1.11Distortion.134.1.11.1Quantizingdistortion.134.1.11.2Totaldistortion.134.1.12Singletoneinterference.134.1.13Frequencyerror.144.1.14Harmonicdistortion.144.1.15Echoandstability.144.1.15.1Echo.144.1.15.1.1Echocontroldevices.144.1.15.1.2Talkerecho.144.1.15.1.3Listenerecho.144.1.15.2Stability.144.2Interfacepresentation.144.2.1Connectorspecification.154.2.2Hardwiredpresentation.154.2.3Returnloss.154.2.4Powerfeeding.164.3Safety.164.4Overvoltage.164.5ElectroMagneticCompatibility(EMC).164.6Availability.16AnnexA(normative):Testmethods.17A.1General.17A.1.1Equipmentconnection.17A.1.2Referenceimpedance.17A.1.3Non-reactivelinetermination.18SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)4A.1.4Measurementfrequency.18A.2Testmethods.18A.2.1Overallloss.18A.2.2Loss/frequencydistortionandmaximummeaninputpower.19A.2.3Maximuminstantaneouspower.19A.2.4Groupdelaydistortion.20A.2.5Amplitudehits.20A.2.6Randomcircuitnoise.21A.2.7Impulsivenoise.21A.2.8Phasejitter.22A.2.9Totaldistortion.22A.2.10Singletoneinterference.23A.2.11Frequencyerror.23A.2.12Harmonicdistortion.24A.2.13Stability.24A.2.14Returnloss.25A.2.15Powerfeeding.26AnnexB(informative):Weightedreturnlossmeasurements.27B.1Introduction.27B.2Weightingfunction.27B.2.1Calculation(trapezoidalrule).27B.2.2Calculation(tabulateddata).28AnnexC(informative):Overalllossandquantizingdistortion.29C.1Introduction.29C.2Overallloss.30C.3Quantizingdistortion.31AnnexD(informative):Availability.32D.1General.32D.1.1Unavailability.32D.1.2Availability.32D.2Definitionofunavailabilityperiods.32D.3Availabilityfigures.34AnnexE(informative):Bibliography.35History.36SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)5IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinETSISR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinETSISR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyETSITechnicalCommitteeAccessandTerminals(AT).ThepresentdocumentresultedfromamandatefromtheCommissionoftheEuropeanCommunity(CEC)toprovidestandardsforsupportoftheDirectiveonOpenNetworkProvision(ONP)ofleasedlines(92/44/EEC).Thereisanotherstandarddirectlyrelatedtothepresentdocument:-EN300450:"AccessandTerminals(AT);OrdinaryandSpecialqualityvoicebandwidth2-wireanalogueleasedlines(A2OandA2S);Terminalequipmentinterface".ThepresentdocumentisbasedoninformationfromITU-TRecommendationsandETSIpublicationsandtherelevantdocumentsarequotedwhereappropriate.NationaltranspositiondatesDateofadoptionofthisEN:29June2001DateoflatestannouncementofthisEN(doa):30September2001DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31March2002DateofwithdrawalofanyconflictingNationalStandard(dow):31March2002IntroductionTheCouncilDirectiveontheapplicationofONPtoleasedlines(92/44/EEC)(seeannexE)concernstheharmonizationofconditionsforopenandefficientaccessto,anduseof,theleasedlinesprovidedoverpublictelecommunicationsnetworks,andtheavailabilitythroughouttheEuropeanUnion(EU)ofaminimumsetofleasedlineswithharmonizedtechnicalcharacteristics.TheconsequenceoftheDirectiveisthattelecommunicationsorganizationswithintheEUshallmakeavailableasetofleasedlineswithinandbetweenpointsinthesecountrieswithspecifiedconnectioncharacteristicsandspecifiedinterfaces.UndertheDirective91/263/EEC(seeannexE),laterreplacedby98/13/EC(seeannexE),terminalequipmentforconnectiontotheseleasedlineswasrequiredtofulfilcertainessentialrequirements.Thepresentversionofthepresentdocumenthasbeenproducedtointroducesomenecessarychanges.ITU-TRecommendationM.1020(seeannexE)wasusedasthebasisfortheconnectioncharacteristics.SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)61ScopeThepresentdocumentspecifiesthetechnicalrequirementsandtestprinciplesfortheconnectioncharacteristicsandthephysicalandelectricalcharacteristics(exceptsafety,overvoltageandEMCaspects)ofthenetworkinterfacepresentationofspecialquality,voicebandwidth,2-wire,analogueleasedlines,providedaspartoftheminimumsetundertheCouncilDirectiveontheapplicationofOpenNetworkProvision(ONP)toleasedlines(92/44/EEC)(seeannexE).AconnectionispresentedviainterfacesatNetworkTerminationPoints(NTPs)andincludesanyequipmentthatmayprovidetheNTP.Signalsbetweenterminalequipmentsaresubjecttoimpairmentsduringtheirtransferovertheconnection.Thelimitstotheseimpairmentsarestatedinthepresentdocumentalthoughinpracticetheoverallperformancemaybeconsiderablybetter.Theleasedlineprovidesaccesstothevoicebandwidth(300Hzto3400Hz)withnorestrictionsontheuseofthefrequencies.Therequirementsofthepresentdocumenthavebeenchosenprimarilyforthetransmissionofdatabetweenterminalequipmentswithoutequalizersalthoughthereisnorestrictionontheuseoftheleasedlineforothertypesoftraffic.Thepresentdocumentisapplicabletoleasedlines,includingparttimeleasedlines,forwhichtheestablishmentorreleasedoesnotrequireanyprotocolexchangeorotherinterventionattheNTP.Thetestsspecifiedinthepresentdocumentcannotbecarriedout,norcanperformancebemonitoredbytheleasedlineprovider,whiletheleasedlineisinservice,i.e.carryinguser'straffic.Thusthetestsaredesignedforbringingintoandreturningintoservicealthoughthereisnoobligationtoperformthesetestseachtimetheleasedlineisbroughtintoorreturnedintoservice.Thepresentdocumentcoversthephysical,mechanicalandelectricalcharacteristicsofthenetworkinterfaceandspecifiestheconformancetestsfortheconnectioncharacteristicsandnetworkinterface.Someofthetestsdescribedinthepresentdocumentarenotdesignedtobeappliedtotheinterfaceofaninstalledleasedline;suchtestsmaybeappliedtoequipmentofthekindusedtoprovidetheinterface.Thepresentdocumentdoesnotincludedetailsconcerningtheimplementationofthetestsnordoesitincludeinformationonanyregulationsconcerningtesting.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.[1]ITU-TRecommendationO.71(1988):"Impulsivenoisemeasuringequipmentfortelephone-typecircuits".[2]ITU-TRecommendationO.81(1988):"Group-delaymeasuringequipmentfortelephone-typecircuits".[3]ITU-TRecommendationO.91(1988):"Phasejittermeasuringequipmentfortelephone-typecircuits".[4]ITU-TRecommendationO.95(1988):"Phaseandamplitudehitcountersfortelephone-typecircuits".[5]ITU-TRecommendationO.132(1988):"Quantizingdistortionmeasuringequipmentusingasinusoidaltestsignal".SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)7[6]ISO/IEC8877(1992):"Informationtechnology.Telecommunicationsandinformationexchangebetweensystems.InterfaceconnectorandcontactassignmentsforISDNBasicAccessInterfacelocatedatreferencepointsSandT".[7]ITU-TRecommendationO.41(1994):"Psophometerforuseontelephone-typecircuits".[8]ETSIEN300450:"AccessandTerminals(AT);OrdinaryandSpecialqualityvoicebandwidth2-wireanalogueleasedlines(A2OandA2S);Terminalequipmentinterface".3Definitions,symbolsandabbreviations3.1DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:groupdelay:measureofthepropagationtimethroughtheleasedline.Foragivenfrequencyitisequaltothefirstderivativeofthephaseshiftthroughtheleasedline,measuredinradians,withrespecttotheangularfrequencymeasuredinradianspersecondgroupdelaydistortion:differencebetweengroupdelayatagivenfrequencyandminimumgroupdelay,inthefrequencybandofinterestleasedlines:telecommunicationsfacilitiesprovidedbyapublictelecommunicationnetworkthatprovidedefinedtransmissioncharacteristicsbetweennetworkterminationpointsandthatdonotincludeswitchingfunctionsthattheusercancontrol,(e.g.on-demandswitching)NetworkTerminationPoint(NTP):allphysicalconnectionsandtheirtechnicalaccessspecificationswhichformpartofthepublictelecommunicationsnetworkandarenecessaryforaccesstoandefficientcommunicationthroughthatpublicnetworkreferenceimpedanceZR:compleximpedancemadeupofaresistanceof270Ωinserieswithaparallelcombinationof750Ωand150nF.SeealsoclauseA.1.2terminalequipment:equipmentintendedtobeconnectedtothepublictelecommunicationnetwork;i.e.:-tobeconnecteddirectlytotheterminationofapublictelecommunicationnetwork;or-tointerworkwithapublictelecommunicationnetworkbeingconnecteddirectlyorindirectlytotheterminationofapublictelecommunicationnetwork,inordertosend,process,orreceiveinformation.voicebandwidth:bandoffrequenciesovertherange300Hzto3400Hz3.2SymbolsandabbreviationsForthepurposesofthepresentdocument,thefollowingsymbolsandabbreviationsapply:aReturnlossindBaf()ReturnlossatfrequencyfindBawWeightedreturnlossindBAf()ReturnlossatfrequencyfexpressedasaratioA2SSpecialqualityvoicebandwidth2-wireanalogueleasedlineADPCMAdaptiveDifferentialPulseCodedModulationEMCElectroMagneticCompatibilityffrequencyNTPNetworkTerminationPointONPOpenNetworkProvisionSIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)8qduquantizingdistortionunitrmsrootmeansquareZRReferenceimpedance4Requirements4.1ConnectioncharacteristicsThespecialqualityvoicebandwidth2-wireanalogueleasedlineisabidirectionalline,configuredpoint-to-point,nominallycoveringthevoicebandwidth.Theconnectionis,ingeneral,symmetrical,i.e.eachdirectionoftransmissionhasthesamenominalcharacteristics,althoughtheactualvaluesareindependent.4.1.1TabulationofconnectioncharacteristicsTheparametersdefiningthecharacteristicsoftheconnectionaregivenintable1.Thesecharacteristicsdefinetheserviceoffered.Table1:NetworkperformancecharacteristicsDescriptionNatureReferenceclauseOverallloss0≤overallloss≤17dB4.1.2Loss/frequencydistortiontable2,figure14.1.3Transmissionsignals-maximummeaninputpower-maximuminstantaneouspower-maximumpowerina10Hzbandwidth-maximuminputpoweroutsidevoiceband-9dBm+4dBmnorequirementnorequirement4.1.44.1.4.14.1.4.24.1.4.34.1.4.4Transmissiondelay-terrestrial(fordistanceGinkilometres)-viasatellite<(15+0,01G)ms<350ms4.1.5Groupdelaydistortiontable3,figure34.1.6Variationofoveralllosswithtime-amplitudehits-othervariations≤10ina15minuteperiod±4dBofthatat1020Hz4.1.74.1.7.14.1.7.2Randomcircuitnoise<-41dBm0p(seenote)4.1.8Impulsivenoise≤18peaks≥-21dBm0ina15minuteperiod(seenote)4.1.9Phasejitter≤10°peaktopeak4.1.10Totaldistortion-quantizingdistortion-totaldistortion≤3qdu;noADPCM>28dBsignaltodistortionratio4.1.114.1.11.14.1.11.2Singletoneinterference≤-44dBm0(seenote)4.1.12Frequencyerror≤±5Hz4.1.13Harmonicdistortion≥25dBbelowfundamental4.1.14Echoandstability-Echocontroldevices-Talkerecho-Listenerecho-Stabilitynoechocontrol>10dB>20dB0to4kHz4.1.154.1.15.1.14.1.15.1.24.1.15.1.34.1.15.2NOTE:Wheretheoutputrelativelevelisnotdefined,analternativevalueisspecifiedinthereferenceclause.SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)94.1.2OveralllossRequirement:Theoverallloss,includinglongtermvariations,presentedtoasignalfrequencyof1020Hzsentatapowerlevelof-9dBmineachdirectionoftransmissionwiththelineterminatedin600Ωateachendshallbeintherange:0≤overallloss≤17dBNOTE:Theoveralllossineachdirectioncanbedifferent.Test:ThetestshallbeconductedaccordingtoclauseA.2.1.4.1.3Loss/frequencydistortionRequirement:Theoveralllossrelativetothatdefinedinclause4.1.2abovefortheconnection,presentedtoasignalsentatapowerlevelof-9dBmwiththelineterminatedin600Ωateachendshallliebetweenthelimitsgivenintable2andfigure1.Below300Hzandabove3600Hztherelativelossshallnotbelessthan-2dBand0dBrespectively,butisotherwiseunspecified.Table2:Limitsforlossofthecircuitrelativetothatat1020HzUpperlimitLowerlimitPoint(seefigure1)FrequencyHzRelativelossdBPoint(seefigure1)FrequencyHzRelativelossdBA3006G500-2B5006H500-1C5003I2800-1D28003J2800-2E28006K3600-2F30006L36000300500FrequencyHz0-1-236RelativelossdB2800360030001020ABCDEFGHIJKLFigure1:Limitsforlossofthecircuitrelativetothatat1020HzTest:ThetestshallbeconductedaccordingtoclauseA.2.2.SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)104.1.4Transmissionsignals4.1.4.1MaximummeaninputpowerRequirement:Theleasedlineshallbecapableofcarryinganysignalpresentedattheinputataoneminutemeanpowerlevelof-9dBmwithinavoicebandwidthof300Hzto3400Hzwiththelineterminatedin600Ωateachend.Test:ThetestshallbeconductedaccordingtoclauseA.2.2.4.1.4.2MaximuminstantaneouspowerRequirement:Theleasedlineshallbecapableofcarryingasignalattheinputhavingamaximumvalueequaltoaninstantaneouspowerwhichis13dBabovethemeanvalueof-9dBm(i.e.+4dBm).NOTE:ThisvalueisbaseduponaprovisionalITU-Tvalue.SeeITU-TRecommendationV.2(seeannexE).Test:ThetestshallbeconductedaccordingtoclauseA.2.3.4.1.4.3Maximumpowerina10HzbandwidthThereisnorequirementformaximumpowerina10Hzbandwidth.NOTE:However,thereisacorrespondingrequirementontheterminalequipmentspecifiedinEN300450[8].4.1.4.4MaximuminputpoweroutsidethevoicebandNOTE:Theleasedlineinterfaceisnotsuitableforthehandlingofsignalsbelow300Hzandabove3400Hz.Outofbandsignalsfromtheterminalequipmentarelimitedtoavoidtroubleinthenetwork(seeterminalequipmentinterfacerequirementinEN300450[8]).4.1.5TransmissiondelayRequirement:Therequirementdependsuponwhethersatellitetransmissionisinvolvedintheconnectionornot:a)forconnectionswheresatellitetransmissionisnotinvolvedtheonewayend-to-enddelayshallbelessthan(15+0,01G)ms,whereGisthegeographicaldistanceinkilometres,asshowninfigure2;orb)forconnectionswheresatellitetransmissionisinvolvedtheonewayend-to-enddelayshallbelessthan350ms.NOTE:Requirementsa)andb)arebasedonclausesA.2andA.3ofITU-TRecommendationG.114(seeannexE)withsuitableadjustmenttorequirementa)toallowforthepossibleuseofloadedcable.SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)11Delay(ms)Geographicaldistance(km)100090003000600010015Figure2:UpperlimitofdelayTest:Thereisnotest.Thisrequirementshallbecheckedbycalculationusinginformationfromthenetworkplans.4.1.6GroupdelaydistortionRequirement:Theconnectionshallconformtothelimitsforgroupdelaydistortiongivenintable3andfigure3inwhichthelimitingvaluesoverthefrequencybandareexpressedasvaluesrelativetotheminimummeasuredgroupdelayinthe500Hzto2800Hzfrequencyband.NOTE:Figure3isbasedonfigure2ofITU-TRecommendationM.1020(seeannexE).Table3:Limitsforgroupdelayrelativetotheminimummeasuredgroupdelayinthe500Hzto2800HzbandUpperlimitPoint(seefigure3)FrequencyHzGroupdelaydistortionmsA5003,0B6003,0C6001,5D10001,5E10000,5F26000,5G26003,0H28003,0SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)12300500FrequencyHz2800260001234Groupdelaydistortionms56001000ABCDEFGHFigure3:Limitsforgroupdelayrelativetotheminimummeasuredgroupdelayinthe500Hzto2800HzbandTest:ThetestshallbeconductedaccordingtoclauseA.2.4.4.1.7Variationofoveralllosswithtime4.1.7.1AmplitudehitsRequirement:WhenmeasurementsaremadeusinganinstrumentcomplyingwithITU-TRecommendationO.95[4]withthesendlevelsetat-9dBmatafrequencyof1020Hz,thenumberofamplitudehitsgreaterthan±2dBshallnotexceed10inany15minutemeasuringperiod.NOTE:Phaseoramplitudehitsaredefinedassuddenpositiveornegativechangesinphaseoramplitudeofanobservedtestsignalwhichexceedaspecifiedthresholdandpersistforaperiodoftimegreaterthanaspecifiedduration.Test:ThetestshallbeconductedaccordingtoclauseA.2.5.4.1.7.2OthervariationsRequirement:Foraparticularimplementationvariationswithtimeoftheoveralllossat1020Hz(includingdailyandseasonalvariationsbutexcludingamplitudehits)shallnotexceed±4dBvariationfromthevalueestablishedbythetestforoverallloss,seeclause4.1.2.Anysuchvariationshallnotresultinanoveralllossgreaterthanthemaximumspecifiedinclause4.1.2.Test:Thereisnotestforthisbuttherecordoftheresultsofsuccessivetestsofoveralllossmaybeusedtocheckcompliance.ThetestshallbeconductedaccordingtoclauseA.2.1.4.1.8RandomcircuitnoiseRequirement:Thelevelofthepsophometricnoisepowerattheoutputoftheleasedlineshallbelessthan-41dBm0p.Inorderthatthisparametercanbetested,theleasedlineprovidershoulddeclaretheplannedvalueoftheoutputrelativeleveloftheleasedline.SIST EN 300 449 V1.2.1:2004



ETSIETSIEN300449V1.2.1(2001-07)13Wheretheoutputrelativeleveleitherisnot,orcannotbe,declaredbytheleasedlineprovider,thepsophometricallyweightedrandomcircuitnoiselevelshallbe28dBbelowareceivedtestsignalwhichissentatalevelof-9dBmatafrequencyof1020Hzintothefarendoftheleasedline.Test:ThetestshallbeconductedaccordingtoclauseA.2.6.4.1.9ImpulsivenoiseRequirement:Withaninputsignallevelof-9dBmappliedatafrequencyof1020Hztotheinputoftheleasedline,theresha
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