ITU-T G.992.1 Amendment 1 (03 2003)(英)Asymmetric d

INTERNATIONALTELECOMMUNICATIONUNIONITU-TG.992.1TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITUAmendment1(03/2003)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitalsectionsanddigitallinesystem–AccessnetworksAsymmetricdigitalsubscriberline(ADSL)transceiversAmendment1:RevisedAnnexC,newAnnexIandnewAppendixVITU-TRecommendationG.992.1(1999)–Amendment1ITU-TG-SERIESRECOMMENDATIONSTRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSINTERNATIONALTELEPHONECONNECTIONSANDCIRCUITSG.100–G.199GENERALCHARACTERISTICSCOMMONTOALLANALOGUECARRIER-TRANSMISSIONSYSTEMSG.200–G.299INDIVIDUALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONMETALLICLINESG.300–G.399GENERALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONRADIO-RELAYORSATELLITELINKSANDINTERCONNECTIONWITHMETALLICLINESG.400–G.449COORDINATIONOFRADIOTELEPHONYANDLINETELEPHONYG.450–G.499TESTINGEQUIPMENTSG.500–G.599TRANSMISSIONMEDIACHARACTERISTICSG.600–G.699DIGITALTERMINALEQUIPMENTSG.700–G.799DIGITALNETWORKSG.800–G.899DIGITALSECTIONSANDDIGITALLINESYSTEMG.900–G.999GeneralG.900–G.909ParametersforopticalfibrecablesystemsG.910–G.919Digitalsectionsathierarchicalbitratesbasedonabitrateof2048kbit/sG.920–G.929Digitallinetransmissionsystemsoncableatnon-hierarchicalbitratesG.930–G.939DigitallinesystemsprovidedbyFDMtransmissionbearersG.940–G.949DigitallinesystemsG.950–G.959DigitalsectionanddigitaltransmissionsystemsforcustomeraccesstoISDNG.960–G.969OpticalfibresubmarinecablesystemsG.970–G.979OpticallinesystemsforlocalandaccessnetworksG.980–G.989AccessnetworksG.990–G.999QUALITYOFSERVICEANDPERFORMANCE-GENERICANDUSER-RELATEDASPECTSG.1000–G.1999TRANSMISSIONMEDIACHARACTERISTICSG.6000–G.6999DIGITALTERMINALEQUIPMENTSG.7000–G.7999DIGITALNETWORKSG.8000–G.8999Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.G.992.1(1999)/Amd.1(03/2003)iITU-TRecommendationG.992.1Asymmetricdigitalsubscriberline(ADSL)transceiversAmendment1RevisedAnnexC,newAnnexIandnewAppendixVSummaryThisamendmentprovidestheG.992.1revision(revisionofAnnexC,additionofAnnexIandadditionofAppendixV).ItincludesthechangesintroducedbyG.992.1(1999)Corrigendum2.RevisedAnnexCcoversspecificrequirementsforanADSLsystemoperatinginthesamecableasISDNasdefinedinAppendixIII/G.961.AnnexIcoversADSLsystemwithimprovedperformanceonshortloopsoperatinginthesamecableasTCM-ISDNasdefinedinAppendixIII/G.961.AppendixVcontainssomeexampleoverlappedPSDMasksforuseinaTCM-ISDNcrosstalkenvironment.SourceAmendment1toITU-TRecommendationG.992.1(1999)wasapprovedbyITU-TStudyGroup15(2001-2004)undertheITU-TRecommendationA.8procedureon16March2003.ThisamendmentincludesITU-TRec.G.992.1(1999)Amendment1/Corrigendum1(12/2003).iiITU-TRec.G.992.1(1999)/Amd.1(03/2003)FOREWORDTheInternationalTelecommunicationUnion(ITU)istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationAssembly(WTSA),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-Tstudygroupswhich,inturn,produceRecommendationsonthesetopics.TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution1.InsomeareasofinformationtechnologywhichfallwithinITU-T'spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendation,theexpressionAdministrationisusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.CompliancewiththisRecommendationisvoluntary.However,theRecommendationmaycontaincertainmandatoryprovisions(toensuree.g.interoperabilityorapplicability)andcompliancewiththeRecommendationisachievedwhenallofthesemandatoryprovisionsaremet.Thewordsshallorsomeotherobligatorylanguagesuchasmustandthenegativeequivalentsareusedtoexpressrequirements.TheuseofsuchwordsdoesnotsuggestthatcompliancewiththeRecommendationisrequiredofanyparty.INTELLECTUALPROPERTYRIGHTSITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.ITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,ITUhadreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementorsarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabase.ITU2004Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.ITU-TRec.G.992.1(1999)/Amd.1(03/2003)iiiCONTENTSPageAmendment1–RevisedAnnexC,newAnnexIandnewAppendixV.................................1AnnexC–SpecificrequirementsforanADSLsystemoperatinginthesamecableasISDNasdefinedinAppendixIIIofITU-TRec.G.961...........