计算机英语 unit7.pptVIP

 New Words Phrases Abbreviations ISDN 综合业务数字网 Integrated Services Digital Network DSL 数字用户线路 Digital Subscriber Line Text and Notes Main Contents The Function of Telecommunications It allows people around the world to contact one another,to access information instantly,and to communication from remote areas. The way in Which telecommunications messages can be sent from one single sender to one receiver (point-to-point)fax message; from one single sender to many receiver (point-to-multipoint)broadcast. The process of telecommunications convert information into electronical signals; send the signals over a medium to a receiver; receiver decode the signal into a form that can be understand by receiver. Devices to transmit signals: telegraph,telephones,radio and television.(analog transmission) Transmission Media: copper wires,fiber-optic cables,communication satellites and microwave radio. Wireless Communication Technologies: cordless phones,cellular radio telephones,walkie-talkies,citizens band radios,pagers,and satellites. Whats a E-mail? It is a text-based message delivery system that allows information such as typed messages and multimedia to be sent to individual computer users. Homework Do exercises of section A； Read section B and section C independently * * Computer English Unit 7 Computer Communications Section A Telecommunications and Computer facsimile n. 传真 telegraph n. 电报 fiber-optic a. 光纤的 walkie-talkie n. 步话机 pager n. 寻呼机 cellular a. 蜂窝状的，多孔的 subscriber a. 用户 converge n. 会聚，结合 interactive a. 交互式的 upcoming a. 即将来到的 computer terminal 计算机终端 decentralized network 分散型网络 wire-based internal network 基于导线的内部网络 wireless communications 无线通信 telegraph key