ITU-T G.992.3 Amendment 2 (03 2006) (英) Asymmetric

InternationalTelecommunicationUnionITU-TG.992.3TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITUAmendment2(03/2006)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitalsectionsanddigitallinesystem–AccessnetworksAsymmetricdigitalsubscriberlinetransceivers2(ADSL2)Amendment2ITU-TRecommendationG.992.3(2005)–Amendment2ITU-TG-SERIESRECOMMENDATIONSTRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSINTERNATIONALTELEPHONECONNECTIONSANDCIRCUITSG.100–G.199GENERALCHARACTERISTICSCOMMONTOALLANALOGUECARRIER-TRANSMISSIONSYSTEMSG.200–G.299INDIVIDUALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONMETALLICLINESG.300–G.399GENERALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONRADIO-RELAYORSATELLITELINKSANDINTERCONNECTIONWITHMETALLICLINESG.400–G.449COORDINATIONOFRADIOTELEPHONYANDLINETELEPHONYG.450–G.499TRANSMISSIONMEDIACHARACTERISTICSG.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.6999DATAOVERTRANSPORT–GENERICASPECTSG.7000–G.7999ETHERNETOVERTRANSPORTASPECTSG.8000–G.8999ACCESSNETWORKSG.9000–G.9999Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.G.992.3(2005)/Amd.2(03/2006)iITU-TRecommendationG.992.3Asymmetricdigitalsubscriberlinetransceivers2(ADSL2)Amendment2SummaryThisamendmenttoITU-TRec.G.992.3updatestheelectricalcharacteristicsofADSL2transceiversandalsocorrectssomeinaccuraciesandinconsistencies.SourceAmendment2toITU-TRecommendationG.992.3(2005)wasapprovedon29March2006byITU-TStudyGroup15(2005-2008)undertheITU-TRecommendationA.8procedure.iiITU-TRec.G.992.3(2005)/Amd.2(03/2006)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.ITU2006Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.ITU-TRec.G.992.3(2005)/Amd.2(03/2006)iiiCONTENTSPage1)Clause8.5.3.3Duringtheexchangephase..................................................................12)Clause8.6.1Toneordering..........................................................................................13)Clause8.13.2.4–Figure8-25aFlowchartforimplementationoftssivalues.............24)Electricalcharacteristics...............................................................................................25)ClauseK.3.5PTM-TCtransportcapabilities..............................................................3ITU-TRec.G.992.3(2005)/Amd.2(03/2006)1ITU-TRecommendationG.992.3Asymmetricdigitalsubscriberlinetransceivers2(ADSL2)Amendment21)Clause8.5.3.3Du