GB/T 7623-1987

Automatic answering equipment and/or parallel automatic calling equipment on the general switched telephone network， including procedures for bling of echo control devices for both manually and automatically established calls

在电话自动交换网上的自动应答设备和(或)并行自动呼叫设备， 包括人工和自动建立呼叫时使回波控制装置停止工作的规程