SIST EN 300 448 V1.2.1:2004

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Access and Terminals (AT); Ordinary quality voice bandwidth 2-wire analogue leased line (A2O); Connection characteristics and network interface presentation33.040.50Vodi, zveze in tokokrogiLines, connections and circuitsICS:Ta slovenski standard je istoveten z:EN 300 448 Version 1.2.1SIST EN 300 448 V1.2.1:2004en01-oktober-2004SIST EN 300 448 V1.2.1:2004SLOVENSKI
STANDARD



SIST EN 300 448 V1.2.1:2004



ETSIEN300448V1.2.1(2001-07)EuropeanStandard(Telecommunicationsseries)AccessandTerminals(AT);Ordinaryqualityvoicebandwidth2-wireanalogueleasedline(A2O);ConnectioncharacteristicsandnetworkinterfacepresentationSIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)2ReferenceREN/AT-010001KeywordsONP,leasedlineETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:+33492944200Fax:+33493654716SiretN°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:editor@etsi.frCopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2001.Allrightsreserved.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)3ContentsIntellectualPropertyRights.5Foreword.5Introduction.51Scope.62References.63Definitions,symbolsandabbreviations.73.1Definitions.73.2Symbolsandabbreviations.74Requirements.84.1Connectioncharacteristics.84.1.1Tabulationofconnectioncharacteristics.84.1.2Overallloss.84.1.3Loss/frequencydistortion.94.1.4Transmissionsignals.94.1.4.1Maximummeaninputpower.94.1.4.2Maximuminstantaneouspower.104.1.4.3Maximumpowerina10Hzbandwidth.104.1.4.4Maximuminputpoweroutsidethevoiceband.104.1.5Transmissiondelay.104.1.6Groupdelaydistortion.114.1.7Variationofoveralllosswithtime.114.1.7.1Amplitudehits.114.1.7.2Othervariations.114.1.8Randomcircuitnoise.114.1.9Impulsivenoise.114.1.10Phasejitter.114.1.11Distortion.114.1.11.1Quantizingdistortion.114.1.11.2Totaldistortion.124.1.12Singletoneinterference.124.1.13Frequencyerror.124.1.14Harmonicdistortion.124.1.15Echoandstability.124.1.15.1Echo.124.1.15.1.1Echocontroldevices.124.1.15.1.2Talkerecho.124.1.15.1.3Listenerecho.124.1.15.2Stability.124.2Interfacepresentation.134.2.1Connectorspecification.134.2.2Hardwiredpresentation.134.2.3Returnloss.134.2.4Powerfeeding.144.3Safety.144.4Overvoltage.144.5ElectroMagneticCompatibility(EMC).144.6Availability.14AnnexA(normative):Testmethods.15A.1General.15A.1.1Equipmentconnection.15A.1.2Referenceimpedance.15A.1.3Non-reactivelinetermination.16SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)4A.1.4Measurementfrequency.16A.2Testmethods.16A.2.1Overallloss.16A.2.2Loss/frequencydistortionandmaximummeaninputpower.17A.2.3Maximuminstantaneouspower.17A.2.4Randomcircuitnoise.18A.2.5Stability.18A.2.6Returnloss.19A.2.7Powerfeeding.20AnnexB(informative):Weightedreturnlossmeasurements.21B.1Introduction.21B.2Weightingfunction.21B.2.1Calculation(trapezoidalrule).21B.2.2Calculation(tabulateddata).22AnnexC(informative):Overalllossandquantizingdistortion.23C.1Introduction.23C.2Overallloss.24C.3Quantizingdistortion.25AnnexD(informative):Availability.26D.1General.26D.1.1Unavailability.26D.1.2Availability.26D.2Definitionofunavailabilityperiods.26D.3Availabilityfigures.28AnnexE(informative):Bibliography.29History.30SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(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,theleasedlinesprovidedoverpublictelecommunicationnetworks,andtheavailabilitythroughouttheEuropeanUnion(EU)ofaminimumsetofleasedlineswithharmonizedtechnicalcharacteristics.TheconsequenceoftheDirectiveisthattelecommunicationsorganizationswithintheEUshallmakeavailableasetofleasedlineswithinandbetweenpointsinthesecountrieswithspecifiedconnectioncharacteristicsandspecifiedinterfaces.UndertheDirective91/263/EEC(seeannexE),laterreplacedby98/13/EC(seeannexE),terminalequipmentforconnectiontotheseleasedlineswasrequiredtofulfilcertainessentialrequirements.Thepresentversionofthepresentdocumenthasbeenproducedtointroducesomenecessarychanges.ITU-TRecommendationM.1040(seeannexE)wasusedasthebasisfortheconnectioncharacteristics.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)61ScopeThepresentdocumentspecifiesthetechnicalrequirementsandtestprinciplesfortheconnectioncharacteristicsandthephysicalandelectricalcharacteristics(exceptsafety,overvoltageandEMCaspects)ofthenetworkinterfacepresentationofordinaryquality,voicebandwidth,2-wire,analogueleasedlines,providedaspartoftheminimumsetundertheCouncilDirectiveontheapplicationofOpenNetworkProvision(ONP)toleasedlines(92/44/EEC)(seeannexE).AconnectionispresentedviainterfacesatNetworkTerminationPoints(NTPs)andincludesanyequipmentthatmayprovidetheNTP.Signalsbetweenterminalequipmentsaresubjecttoimpairmentsduringtheirtransferovertheconnection.Thelimitstotheseimpairmentsarestatedinthepresentdocumentalthoughinpracticetheoverallperformancemaybeconsiderablybetter.Theleasedlineprovidesaccesstothevoicebandwidth(300Hzto3400Hz)withnorestrictionsontheuseofthefrequencies.Therequirementsofthepresentdocumenthavebeenchosenprimarilyforthetransmissionoftelephonyalthoughthereisnorestrictionontheuseoftheleasedlineforothertypesoftraffic.Thepresentdocumentisapplicableforleasedlines,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]ISO/IEC8877(1992):"Informationtechnology.Telecommunicationsandinformationexchangebetweensystems.InterfaceconnectorandcontactassignmentsforISDNBasicAccessInterfacelocatedatreferencepointsSandT".[2]ITU-TRecommendationO.41(1994):"Psophometerforuseontelephone-typecircuits".[3]ETSIEN300450:"AccessandTerminals(AT);OrdinaryandSpecialqualityvoicebandwidth2-wireanalogueleasedlines(A2OandA2S);Terminalequipmentinterface".SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)73Definitions,symbolsandabbreviations3.1DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:groupdelay:measureofthepropagationtimethroughtheleasedline.Foragivenfrequencyitisequaltothefirstderivativeofthephaseshiftthroughtheleasedline,measuredinradians,withrespecttotheangularfrequencymeasuredinradianspersecondgroupdelaydistortion:differencebetweengroupdelayatagivenfrequencyandminimumgroupdelay,inthefrequencybandofinterestleasedlines:telecommunicationsfacilitiesprovidedbyapublictelecommunicationnetworkthatprovidedefinedtransmissioncharacteristicsbetweennetworkterminationpointsandthatdonotincludeswitchingfunctionsthattheusercancontrol,(e.g.on-demandswitching)NetworkTerminationPoint(NTP):allphysicalconnectionsandtheirtechnicalaccessspecificationswhichformpartofthepublictelecommunicationnetworkandarenecessaryforaccesstoandefficientcommunicationthroughthatpublicnetworkreferenceimpedanceZR:compleximpedancemadeupofaresistanceof270Ωinserieswithaparallelcombinationof750Ωand150nF.SeealsoclauseA.1.2terminalequipment:equipmentintendedtobeconnectedtothepublictelecommunicationnetwork;i.e.:-tobeconnecteddirectlytotheterminationofapublictelecommunicationnetwork;or-tointerworkwithapublictelecommunicationnetworkbeingconnecteddirectlyorindirectlytotheterminationofapublictelecommunicationnetwork,inordertosend,process,orreceiveinformation.voicebandwidth:bandoffrequenciesovertherange300Hzto3400Hz3.2SymbolsandabbreviationsForthepurposesofthepresentdocument,thefollowingsymbolsandabbreviationsapply:aReturnlossindB)(faReturnlossatfrequencyfindBwaWeightedreturnlossindB)(fAReturnlossatfrequencyfexpressedasaratioA2OOrdinaryqualityvoicebandwidth2-wireanalogueleasedlineADPCMAdaptiveDifferentialPulseCodedModulationEMCElectroMagneticCompatibilityffrequencyFDMFrequencyDivisionMultiplexingNTPNetworkTerminationPointONPOpenNetworkProvisionqduquantizingdistortionunitTDMTimeDivisionMultiplexingZRReferenceimpedanceSIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)84Requirements4.1ConnectioncharacteristicsTheordinaryqualityvoicebandwidth2-wireanalogueleasedlineisabi-directionalline,configuredpoint-to-point,nominallycoveringthevoicebandwidth.Theconnectionis,ingeneral,symmetrical,i.e.eachdirectionoftransmissionhasthesamenominalcharacteristics,althoughtheactualvaluesareindependent.4.1.1TabulationofconnectioncharacteristicsTheparametersdefiningthecharacteristicsoftheconnectionaregivenintable1.Thesecharacteristicsdefinetheserviceoffered.Table1:NetworkperformancecharacteristicsDescriptionNatureReferenceclauseOverallloss0≤overallloss≤25dB4.1.2Loss/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<350ms4.1.5Groupdelaydistortionnorequirement4.1.6Variationofoveralllosswithtime-amplitudehits-othervariationsnorequirement±4dBofthatat1020Hz4.1.74.1.7.14.1.7.2Randomcircuitnoise<-41dBm0p(seenote)4.1.8Impulsivenoisenorequirement4.1.9Phasejitternorequirement4.1.10Totaldistortion-quantizingdistortion-totaldistortion≤7,5qdu;≤1ADPCMsystemnorequirement4.1.114.1.11.14.1.11.2Singletoneinterferencenorequirement4.1.12Frequencyerrornorequirement4.1.13Harmonicdistortionnorequirement4.1.14Echoandstability-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.4.1.2OveralllossRequirement:Theoverallloss,includinglongtermvariations,presentedtoasignalfrequencyof1020Hzsentatapowerlevelof-9dBmineachdirectionoftransmissionwiththelineterminatedin600Ωateachendshallbeintherange:0≤overallloss≤25dB.NOTE:Theoveralllossineachdirectioncanbedifferent.Test:ThetestshallbeconductedaccordingtoclauseA.2.1.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)94.1.3Loss/frequencydistortionRequirement:Theoveralllossrelativetothatdefinedinclause4.1.2abovefortheconnection,presentedtoasignalsentatapowerlevelof-9dBmwiththelineterminatedin600Ωateachendshallliebetweenthelimitsgivenintable2andfigure1.Below400Hzandabove3600Hztherelativelossshallnotbelessthan-4dBand0dBrespectively,butisotherwiseunspecified.Table2:Limitsforlossofthecircuitrelativetothatat1020HzUpperlimitLowerlimitPoint(seefigure1)FrequencyHzRelativelossdBPoint(seefigure1)FrequencyHzRelativelossdBA4009E400-4B20009F400-3C200016G3600-3D280016H360003002000FrequencyHz40036000916-32800ABCDGHRelativelossdB1020-4EFFigure1:Limitsforlossofthecircuitrelativetothatat1020HzTest:ThetestshallbeconductedaccordingtoclauseA.2.2.4.1.4Transmissionsignals4.1.4.1MaximummeaninputpowerRequirement:Theleasedlineshallbecapableofcarryinganysignalpresentedattheinputataoneminutemeanpowerlevelof-9dBmwithinavoicebandwidthof300Hzto3400Hzwiththelineterminatedin600Ωateachend.Test:ThetestshallbeconductedaccordingtoclauseA.2.2.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)104.1.4.2MaximuminstantaneouspowerRequirement:Theleasedlineshallbecapableofcarryingasignalattheinputhavingamaximumvalueequaltoaninstantaneouspowerwhichis13dBabovethemeanvalueof-9dBm(i.e.+4dBm).NOTE:ThisvalueisbaseduponaprovisionalITU-Tvalue.SeeITU-TRecommendationV.2(seeannexE).Test:ThetestshallbeconductedaccordingtoclauseA.2.3.4.1.4.3Maximumpowerina10HzbandwidthThereisnorequirementformaximumpowerina10Hzbandwidth.NOTE:However,thereisacorrespondingrequirementontheterminalequipmentspecifiedinEN300450[3].4.1.4.4MaximuminputpoweroutsidethevoicebandNOTE:Theleasedlineinterfaceisnotsuitableforthehandlingofsignalsbelow300Hzandabove3400Hz.Outofbandsignalsfromtheterminalequipmentarelimitedtoavoidtroubleinthenetwork(seeterminalequipmentinterfacerequirementinEN300450[3]).4.1.5TransmissiondelayRequirement:Therequirementdependsuponwhethersatellitetransmissionisinvolvedintheconnectionornot:a)forconnectionswheresatellitetransmissionisnotinvolvedtheonewayend-to-enddelayshallbelessthan(15+0,01G)ms,whereGisthegeographicaldistanceinkilometres,asshowninfigure2;orb)forconnectionswheresatellitetransmissionisinvolvedtheonewayend-to-enddelayshallbelessthan350ms.NOTE:Requirementsa)andb)arebasedonclauses2.2and2.3ofITU-TRecommendationG.114(seeannexE),withsuitableadjustmenttorequirementa)toallowforthepossibleuseofloadedcable.Delay(ms)Geographicaldistance(km)100090003000600010015Figure2:UpperlimitofdelayTest:Thereisnotest.Thisrequirementshallbecheckedbycalculationusinginformationfromthenetworkplans.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)114.1.6GroupdelaydistortionThereisnorequirementforgroupdelaydistortion.NOTE:Groupdelaydistortionisnotconsideredtobeimportantforvoicecommunication.Terminalequipmentforotherpurposeswhichwishestomakeuseofleasedlinesconformingtothepresentdocumentwillneedtocompensateforpossibleshortcomingsduetogroupdelaydistortion.4.1.7Variationofoveralllosswithtime4.1.7.1AmplitudehitsThereisnorequirementforamplitudehits.NOTE:Phaseoramplitudehitsaredefinedassuddenpositiveornegativechangesinphaseoramplitudeofanobservedtestsignalwhichexceedaspecifiedthresholdandpersistforaperiodoftimegreaterthanaspecifiedduration.4.1.7.2OthervariationsRequirement:Foraparticularimplementation,variationswithtimeoftheoveralllossat1020Hz(includingdailyandseasonalvariationsbutexcludingamplitudehits)shallnotexceed±4dBvariationfromthevalueestablishedbythetestforoverallloss,seeclause4.1.2.Anysuchvariationshallnotresultinanoveralllossgreaterthanthemaximumspecifiedinclause4.1.2.Test:thereisnotestforthisbuttherecordoftheresultsofsuccessivetestsofoveralllossmaybeusedtocheckcompliance.ThetestshallbeconductedaccordingtoclauseA.2.1.4.1.8RandomcircuitnoiseRequirement:Thelevelofthepsophometricnoisepowerattheoutputoftheleasedlineshallbelessthan-41dBm0p.Inorderthatthisparametercanbetested,theleasedlineprovidershoulddeclaretheplannedvalueoftheoutputrelativeleveloftheleasedline.Wheretheoutputrelativeleveleitherisnot,orcannotbe,declaredbytheleasedlineprovider,thepsophometricallyweightedrandomcircuitnoiselevelshallbe28dBbelowareceivedtestsignalwhichissentatalevelof-9dBmatafrequencyof1020Hzintothefarendoftheleasedline.Test:ThetestshallbeconductedaccordingtoclauseA.2.4.4.1.9ImpulsivenoiseThereisnorequirementforimpulsivenoise.4.1.10PhasejitterThereisnorequirementforphasejitter.4.1.11Distortion4.1.11.1QuantizingdistortionRequirement:Thequantizingdistortionshallnotexceed7,5quantizingdistortionunit(qdu).Moreover,withinthislimit,nomorethanoneAdaptiveDifferentialPulseCodedModulation(ADPCM)systemshallbeused.Test:Thereisnotest.Thisrequirementshallbecheckedbycalculationusinginformationfromthenetworkplans.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)124.1.11.2TotaldistortionThereisnorequirementfortotaldistortion.4.1.12SingletoneinterferenceThereisnorequirementforsingletoneinterference.4.1.13FrequencyerrorThereisnorequirementforfrequencyerror.4.1.14HarmonicdistortionThereisnorequirementforharmonicdistortion.4.1.15Echoandstability4.1.15.1Echo4.1.15.1.1EchocontroldevicesRequirement:Inordertofacilitatedatatransmission,echocontroldevicesshallnotbeusedintheconnection.Test:Thereisnotest.Thisrequirementshallbecheckedusinginformationfromthenetworkplans.4.1.15.1.2TalkerechoRequirement:Withaninputsignallevelof-9dBminthefrequencyrange500Hzto2500Hzappliedattheinterface,withasourceimpedanceof600Ω,anycompositeechosignalreceivedatthenearendinterfaceshallbegreaterthan10dBbelowthesignalleveltransmittedintotheinterface(i.e.<-19dBm).Test:Thereisnotest.Thisrequirementshallbecheckedbycalculationusinginformationfromthenetworkplans.4.1.15.1.3ListenerechoRequirement:Withaninputsignallevelof-9dBminthefrequencyrange500Hzto2500Hzappliedattheinterface,withasourceimpedanceof600Ω,anycompositeechosignalreceivedatthefarendinterfaceshallbegreaterthan20dBbelowthereceivedlevelofthefundamentalsignal.Test:Thereisnotest.Thisrequirementshallbecheckedbycalculationusinginformationfromthenetworkplans.4.1.15.2StabilityRequirement:Anyleasedlineshallbestableoverthefrequencyrange0Hzto4000Hzforallterminatingconditions.NOTE:Theterm"allterminatingconditions"includesopenandshortcircuitandhighimpedanceterminations.Test:ThetestshallbeconductedaccordingtoclauseA.2.5.SIST EN 300 448 V1.2.1:2004



ETSIETSIEN300448V1.2.1(2001-07)134.2InterfacepresentationThephysicalconnectionarrangementsshallnormallybebyasocketasspecifiedinclause4.2.1.However,atthespecificrequestoftheusertheconnection,arrangementsspecifiedinclause4.2.2shallbeprovided.4.2.1ConnectorspecificationRequirement:Thenetworkinterfaceshallprovidean8-contactsocketofthetypespecifiedinISO/IEC8877[1]andwithcontactassignmentsasspecifiedintable3.Table3:ContactassignmentsContactnumberNetworkinterface1Unused2Unused3Unused4&5Pair6Unused7Unused8UnusedTest:Thereshallbeavisualinspectionthatthesocketisofthecorrecttype.ThecontactassignmentsaretestedindirectlythroughthetestsinannexA.4.2.2HardwiredpresentationRequirement:
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