通信与电子信息专业英语 课件 Unit 10 Telecommunication Networks.pptx

Unit10TelecommunicationNetworks

10.1ATelephoneNetwork

10.2InternetTelephony

10.1AtelephonenetworkWordsandExpressionsBackgroundsText

WordsandExpressionstelephoneexchange电话局；总机；电话交换机；电信交换ubiquitous adj.无处不在的；十分普遍的Sincethen(AlexanderGrahamBellinventedthetelephonein1876,andtheworld’sfirsttelephoneexchangewasopenedin1878),telephonyhasbecometheubiquitousmeansofcommunicatingformankind.从那时起，电话已经成为人类无处不在的通信手段。

WordsandExpressions5vocaltract 声道Duringtalking,variationsinairpressurearegeneratedbythevocaltractofthespeaker.touch-tonekeypad 按键式键盘Atouch-tonephonekeypadproducesaDTMFsignalingtoneconsistingoftwosimultaneouspuretonesinusoidalfrequencieswhenakeyispressed.

WordsandExpressions6scalingproblem 缩放问题；尺度问题call-controlsoftware 呼叫控制软件Today,telephoneexchangesarefullyautomatic,theexchangecontrolisprovidedbycomputerswiththeprocedurescapturedincall-controlsoftware.automanualexchange 半自动交换台；自动手动切换whenahumaninterventionisrequired,forexample,providingvariousformsofassistanceandemergencycalls

WordsandExpressions7PSTN:PublicSwitchedTelephoneNetwork公用电话交换网POTS:PlainOldTelephoneService 普通传统电话业务dialtone 拨号音ThedialtoneisgeneratedbythePSTNexchangetoindicatetothephoneuserthattheexchangewasreadytoacceptthenumber.SLIC:SubscriberLineInterfaceCircuit用户线接口电路；用户接口电路

WordsandExpressions8BORSCHT:Batteryfeed 馈电Overvoltageprotection 过压保护Ringing 振铃Supervision 监视Codec:codinganddecoding 编解码Hybrid 混合（用户线2/4线转换）Test 测试

WordsandExpressions9Vrms:root-mean-squarevoltage电压均方根值；电压有效值trunkline 干线subscriberbranchline 用户分线tolloffice 长途局；长途电话局；长途端局；收费站exchangenumber 交换局号areacode 区号LEC:LocalExchangeCarrier 本地交换运营商/公司

WordsandExpressions10LATA:LocalAccessandTransportAreas本地接入和传输区域IXC:IntereXchangeCarrier 局间通信公司；长途电话公司POP:PointofPresence 入网点；出现点；存在点hierarchical adj