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基础数据业务主要指公共数据传送业务和移动数据业务。公共数据传送业务是利用电路交换、分组交换或租用电路组成的固定公共数据通信网上开放的以传送数据为目的的业务。按照所用技术的不同,公共数据传送业务包括 X.25、DDN、ISDN、帧中继、ATM 和 IP 业务等。其中 X.25、帧中继和 ATM 业务都采用面向连接的分组交换技术,具有统计复用、用户共享网络带宽等功能,但它们所用的通信协议、能提供的接入速
Basic data services mainly refers to public data transfer services and mobile data services. Public data transmission service is to use the open circuit composed of circuit switching, packet switching or leased circuits to open the public data communication network to transmit data for the purpose of the business. Depending on the technology used, public data delivery services include X.25, DDN, ISDN, Frame Relay, ATM and IP services. X.25, Frame Relay and ATM services use connection-oriented packet switching technology, with the functions of statistical multiplexing and user sharing of network bandwidth. However, the communication protocols they use and the access speeds that can be provided