通信英语训练-测试题综合测试一

模拟试卷分题ⅠⅡⅢⅣⅤ一、单项选择题（110分Thecircuitissetupbyaspecialsignalingmessagefindsitswaythroughthenetwork, channelsinthepathasitthat, B.where,C.who, D.one,beAvariationofmessageswitchingispacketswitching.Herethemessageisbrokenupintoseveralpiecesofa given, B.give,C.giving, D.togive,toEachsubscriberconnects locallooptoaswitching asanendoffice.to, B.with,C.the, D.via, ephonesubscribers,the ephonenetworkhandlessubstantialdata modem,andgraduallybeingconvertedtoadigitalimplemented, B.implementing,C.toimplement, D.design,ISDN’senormousimportanceisonlygradually .Yearsofworkhavebeen bytheCCITTandtheunderstand, B.understanded,C.tobeunderstood,to D.understood,carriedSimilarly,theintroductionofvoiceencodingtechniquespulsecodemodulationcontributed theISDN’sconceptusage, B.using,C.use, D.used,soasTheenhancedqualityisachievedwhenasignalisthetransmissione,B.overcame,ing,D. e,dueTheswitchingelementisacomputer amessageprocessor,withprocessingandstoragecapabilities.Messagetravelsindependentlyandasynchronously, theirownwayfromsourcetodestination.tocall, B.calling,C.referredtoas, D.becalled,Designershavefounditconvenient thesenodesintoahierarchyortreetopology, fiveclassesofswitchingcentersornodes. B.organize,C.toorganize,consisting D.organizing,to significantadvantagessinceasubstantial tyinterfaceequipmentin ephoneexchange A.offered,be B.offer,C.offers,is D.tooffer,to二、英译汉短语（每题1分，共15分awelldefinedblockofdatacalledathestore-and-forwardtransmissioncircuitsource-destinationlowdelayconstraintrequiredbythethefunctionofconcentratingthesubscriberthattransmitdigitalthebranchesbetweentreeadjacentendbasicorderoftheintegratedservicesdigitalstandardizedglobalsubstantialtyofinterfacevoiceencoding三、汉译英短语（每题1分，共15分1、报文2、目的3、传输4、报文处理56、交换7、数字数据系8、数据9、半双10、拓11、路12、开放网13、国际标准化组14、带宽限15、基本接四、阅读理解（每题2分，共20分，根据文章内容判断（√（X） Therearetwobasictypesofswitchingtechniques:circuitswitchingandmessageswitching.Incircuitswitching,atotalpathofconnectedlinesissetupfromtheorigintothedestinationatthetimethecallismade,andthepathremainsallocatedtothesource-destinationpair(whetherusedornot)untilitisreleasedbythecommunicatingparties.Theswitches,calledcircuitswitches(orofficeexchangeinephonejargon),havenocapabilityofstoringormanipulatinguser’sdataontheirwaytothedestination.Thecircuitissetupbyaspecialsignalingmessagethatfindsitswaythroughthenetwork,seizingchannelsinthepathasitproceeds.Oncethepathisestablished,areturnsignalinformsthesourcetobegintransmission.Directtransmissionofdatafromsourcetodestinationcanthentakeplacewithoutanyinterventiononthepartofthesubnet.Inmessageswitching,thetransmissionunitisawell-definedblockofdatacalledamessage.Inadditiontothetexttobetransmitted,amessagecomprisesaheaderandachecksum.Theheadercontainsinformationregardingthesourceanddestinationaddressesaswellasothercontrolinformation;thechecksumisusedforerrorcontrolpurposes.Theswitchingelementisacomputerreferredtoasamessageprocessor,withprocessingandstoragecapabilities.Messagestravelindependentlyandasynchronously,findingtheirownwayfromsourcetodestination.Firstthemessageistransmittedformthehosttothemessageprocessortowhichitisattached.Oncethemessageisentirelyreceived,themessageprocessorexaminesitsheader,andaccordinglydecidesonthenextoutgoingchannelonwhichtotransmitit.Ifthisselectedchannelisbusy,themessagewaitsinaqueueuntilthechannel esfree,atwhichtimetransmissionbegins.Atthenextmessageprocessor,themessageisagainreceived,stored,examined,andtransmittedonsomeoutgoingchannel,andthesameprocesscontinuesuntilthemessageisdeliveredtoitsdestination.Thistransmissiontechniqueisalsoreferredtoasthestore-and-forwardtransmissiontechnique.Therearetwobasictypesofswitchingtechniques,messageswitchingandpacketswitching.()Theswitches,calledcircuitswitches(orofficeexchangeinephonejargon),havecapabilityofstoringormanipulatinguser’sdataontheirwaytothedestination.()Inmessageswitching,thetransmissionunitisawell-definedblockofdatacalledamessage.()Amessageonlycomprisesaheaderandachecksum.(Theswitchingelementisacomputerreferredtoasamessageprocessor,withoutprocessingandstoragecapabilities.( Theheaderonlycontainsinformationregardingthesourceanddestinationaddresses.( Theswitches,calledcircuitswitcheshavecapabilityofmanipulatinguse’sdataontheirwaytothedestination.( PASSAGEThetermISDNwasfirstdefinedwithintheCCITTin1972.referredtoanetworkprovidingend-to-enddigitalconnectivityforarangeofservices.Italsousedtheideaofatotallyopennetworkwith everywhere.Theconcepthassincethenevolvedfromtheexisting countries changes introductionoftotallynewdigitaltechnologyintheswitchingandtransmissionequipment.Similarly,theintroductionofvoiceencodingtechniquesusingpulsecodemodulationcontributedtotheconcept’s transmissionrate.Todaytwo64kbit/s,or2B-channelscoupledwithabasicaccesssignalingrateof16kbit/s,thatis,theD-channel,constitutetheessentialIADNtransmissionrateof144kbit/s.CurrentlyPSTN,availableinalmost200countriesandterritoriesaroundtheworld,offersuniversalvoiceaccesstoalmost750million ephonesaroundtheworld.ISDNisthenetworkwhichwillprogressivelyprovideasimilaruniversalaccessfornotonlyvoicebutdata, ,text,andservicesasIntheindustrializedcountries,theevolutionarynatureoftheISDNconcepthasbeenamatterofeconomicpracticalityconsideringtheephoneinfrastructurealreadyinplace.Theprimaryemphasis,however,hasbeentheenhancementoftheservicesratherthanasinglereplacementoftheservicesratherthanasinglereplacementofexistingequipment.Thisevolutionaryapproachhasalsomeritformostofthedevelocountries,althoughinsomeinstanceswhere ogfacilitiesdonotexistpresentlyorwheretheyareverylimited,thedirectinstallationofdigitalfacilitiescouldallowadirectleapfrogtoISDNcapabilities.ManyplannersbelievethatthetransitionformexperimentalISDNtechnologytooperationalsystemwillbeconvincinglymadeinthenextfewyears.Certainlythe1990swillbethetimeofrapidoperationalgrowth.Iftrue,alotofissueswillhavetoberesolvedincomingmonthsratherthanincomingyears.ThecurrentstudyperiodofCCITT(1989～1992)will,ofnecessity,resolvevirtuallyallstandardsissuesonISDNincludingevenwidebandISDNfortransmissionratesupto155Mbit/s.ISDNisnotafour-letterwork.Itisablueprinttotheelectroniccommunicationssystemofthefuture.ThetermISDNwasfirstdefinedwiththeCCITTin1982.(ISDNreferredtoanetworkprovidingend-to-enddigitalconnectivityforarangeofservices.()Todaytwo64kbit/s,or2B-channelscoupledwithabasicaccesssignalingrateof16kbit/s,thatis,theD-channel,constitutetheessentialISDNtransmissionrateof144kbit/s(2B+D).()ISDNisthenetworkwhichwillprogressivelyprovideasimilaruniversalaccessforonlyvoice,facsiand.()ISDNisablueprinttotheelectroniccommunicationssystemofthefuture.()TheauthorthinksthatalotofissuesonISDNwillhavetoberesolvedinafewmonths.()五、英译汉短文（每题10分，共40分Messagestravelindependentlyandasynchronously,findingtheirownwayfromsourcetodestination.Firstthemessageistransmittedfromthehosttothemessageprocessortowhichitisattached.Oncethemessageisentirelyreceived,themessageprocessorexaminesitsheader,andaccordinglydecidesonthenextoutgoingchannelonwhichtotransmitit.Ifthisselectedchannelisbusy,themessagewaitsinaqueueuntilthe esfree,atwhichtimetransmissionbegins. municationsnetwork— ephone Thisisactuallyacollectionofnationalnetworksinterconnectedtoformaninternationalservice.Althoughoriginallydesignedandimplementedtoservice ephonesubscribers,ithandlessubstantialdatatrafficviamodem,andisgraduallybeingconvertedtoadigitalEachsubscriberconnec