当使用此标准信号线或交换式信号线在地面上启动时，该标准信号线提供了对地面的监控能力。电信运营商与客户安装布线和设备之间的接口规定了要求。本标准旨在与美国电信国家标准ATIS-0600401.2000（R2005）结合使用。美国电信国家标准-网络到客户安装接口-使用环路启动和地面启动信号的模拟语音级交换接入线路。以前称为T1。401.01-2000（R2005）。

This standard provides the signaling requirements associated with the line-side answer supervision feature on analog switched access lines using loop-started or ground-start signaling when the network provides this capability. Requirements are specified at the interface between telecommunications carriers and customer installation wiring and equipment. This standard is intended to be used in conjunction with American National Standard for Telecommunications - Network-to-Customer Installation Interfaces - Analog Voicegrade Switched Access Lines Using Loop-Start and Ground-Start Signaling, ATIS-0600401.2000(R2005). Formerly known as T1.401.01-2000(R2005).