一、ISDN的概念 综合业务数字网（ＩＳＤＮ）的基本概念是２０世纪７０年代初作为世界通信网发展总目标由原国际电报电话咨询委员会（ＣＣＩＴＴ）提出来的。其定义如下：一般来说，ＩＳＤＮ是从电话综合数字网（ＩＤＮ）发展起来的网络，它提供端到端的数字连接，以支持包括话 I. ISDN Concept The basic concept of Integrated Services Digital Network (ISDN) was proposed by the former International Telegraph and Telephone Consultative Committee (CCITT) in the early 1970s as the overall goal of the development of the world’s telecommunications networks. It is defined as follows: In general, ISDN is a network developed from the Telephone Integrated Digital Network (IDN) that provides an end-to-end digital connection to support both