本标准规定了电信网络和客户安装之间接口的信令要求，其中客户安装提供环路启动监督。这些要求旨在帮助网络运营商、制造商和电信网络产品用户了解现有网络的参数。本标准是T1的修订版。407-1997，它将全部取代。

This standard provides signaling requirements for the interface between telecommunication networks and customer installations where the customer installation provides loop-start supervision. These requirements are intended to assist network operators, manufacturers, and users of products to be used with telecommunication networks to understand the parameters of the existing networks. This standard is a revision of T1.407-1997, which it replaces in its entirety.