scope:

This standard provides the signaling requirements associated with the line-side answer supervision feature on analog switched-access lines using loop-start or ground-start signaling when the network provides this capability. Requirements are specified at the interface between telecommunications carriers and customer premises wiring and equipment. In this standard, the telecommunications carrier network is referred to as the Network and customer premises wiring and equipment is referred to as the Customer Installation (CI). The interface between the Network and the CI is referred to as the Network Interface (NI). 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, T1.401-2000.