Access and Terminals (AT); Analogue access to the Public Switched Telephone Network (PSTN); Protocol over the local loop for display and related services; Terminal equipment requirements; Part 1: On-hook data transmission
接入和终端(AT);公共交换电话网(PSTN)的模拟接入;用于显示和相关服务的本地环路协议;终端设备要求;第1部分:挂机数据传输