实用化的ＩＳＤＮ第一类用户／网络终端设备邮电部第五研究所罗正华ＩＳＤＮ是以综合数字电话网（ＩＤＮ）为基础发展而成的通信网。它以提供用户端到端的数字连接方式，实现在同一网中综合提供广泛的话音和非话业务及其各种应用。用户终端通过一组有限的标准的多用途用户... Practical ISDN first class user / network terminal equipment Fifth Institute of Posts and Telecommunications Luo Zhenghua ISDN is based on the integrated digital telephone network (IDN) as the basis for the development of communication network. It provides a digital end-to-end connection to provide a broad range of voice and non-voice services and their various applications on the same network. User terminal through a limited set of standard multi-purpose users ...