ETSI ES 200 659-3-2004 接入和终端(AT).公用交换电话网(PSTN)的模拟接入.显示(及相关)业务的本地回路用户线协议.第3部分:数据链路消息和参数编码(版本1.4.1)
Access and Terminals (AT); Analogue access to the Public Switched Telephone Network (PSTN); Subscriber line protocol over the local loop for display (and related) services; Part 3: Data link message and parameter codings