数字用户信令 meaning in English

dss digital subscriber signaling

Dss1 - telecommunications - digital subscriber signalling system number 1 - signalling specification for the user signalling bearer service
电信.数字用户信令发送系统no . 1
Integrated services digital network - digital subscriber signalling system no . one protocol - signalling network layer for circuit - mode basic call control - part 1 : protocol specification
综合业务数字网.数字用户信令系统第1协议.电路模式基本呼叫控制用信令网络层.第1部分:协议规范