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一、ISDN1.ISDN定义ISDN（综合业务数字网）是以电话综合数字网为基础发展而来的通信网,能够提供端到端的数字连接,支持包括话音和非话音在内的多种电信业务。用户能通过一组有限的标准多用途用户/网络接口接入该网。ISDN有3个基本特性:一是端到端的数字连接。它是指发端用户送出的信号和接收端用户终端输入的信号都是数字信号,也就是说,在ISDN网中,中继线和
I. Definition of ISDN1.ISDN ISDN (Integrated Services Digital Network) is a communication network based on the integrated telephone network. It can provide end-to-end digital connections and support multiple telecommunication services including voice and non-voice. Users can access the network through a limited set of standard multi-purpose user / network interfaces. ISDN has three basic characteristics: First, end-to-end digital connection. It refers to the sending end user sends the signal and the receiving end user terminal input signals are digital signals, that is, in the ISDN network, trunks and