Recommendation G.991.2 (2001) Amendment 1 (11 2001

INTERNATIONALTELECOMMUNICATIONUNIONITU-TG.991.2TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITUAmendment1(11/2001)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitalsectionsanddigitallinesystem–AccessnetworksSingle-pairhigh-speeddigitalsubscriberline(SHDSL)transceiversAmendment1ITU-TRecommendationG.991.2(2001)–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.999QUALITYOFSERVICEANDPERFORMANCEG.1000–G.1999TRANSMISSIONMEDIACHARACTERISTICSG.6000–G.6999DIGITALTERMINALEQUIPMENTSG.7000–G.7999DIGITALNETWORKSG.8000–G.8999Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.G.991.2/Amd.1(11/2001)iITU-TRecommendationG.991.2Single-pairhigh-speeddigitalsubscriberline(SHDSL)transceiversAmendment1SummaryThisamendmentprovidesalistofidentifieddefectsandassociatedcorrectionstothetextofITU-TRec.G.991.2.Thesedefectsincludetypographicalerrors,technicalerrors,andambiguities.SourceAmendment1toITU-TRecommendationG.991.2(2001)waspreparedbyITU-TStudyGroup15(2001-2004)andapprovedundertheWTSAResolution1procedureon29November2001.iiITU-TRec.G.991.2/Amd.1(11/2001)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.INTELLECTUALPROPERTYRIGHTSITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.ITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,ITUhadreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementorsarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabase.ITU2002Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.ITU-TRec.G.991.2/Amd.1(11/2001)iiiCONTENTSPageIntroduction..............................................................................................................................11)Table6.3,Timingforactivationsignals.......................................................................12)Clause6.2.2.1,SignalCr...............................................................................................13)Clause6.2.2.8,Exceptionstate.....................................................................................14)Clause6.3.2.1,SignalPri..............................................................................................15)Clause6.3.2.2,SignalPci..............................................................................................26)Clause6.4.1,G.994.1codepointdefinitions................................................................27)Clause7.1.2.5.3,fbit3=ps(powerstatus)...................................................................28)Clause9.2.7,Lossofsyncwordfailure(LOSWfailure).............................................29)Clause9.5.5.4,Framechecksequence......................................