scope:

This standard specifies a DS1-rate electrical interface at the network interface (NI) between the network and a customer installation (CI). It establishes requirements at the NI necessary for compatible operation between a network and the CI. This standard specifies a basic DS1 interface, and provides criteria that is common to a set of standards, the T1.403 series, which define specific DS1 applications. The documents which are included in the T1.403 series (at the time that this document is approved) are listed below:

ANSI T1.403.01-1999, Telecommunications - Network and Customer Installation Interfaces - Integrated Services Digital Network (ISDN) Primary Rate Layer 1 Electrical Interface Specification

ANSI T1.403.02-1999, Telecommunications - Network to Customer Installation Interfaces - Robbed-Bit Signaling State Definitions

The requirements in this standard specify a functional and practical interface; compliance with the requirements provides a satisfactory interface in a high percentage of installations. If cases arise that have not been adequately addressed in this standard, any resulting problems should be resolved through the cooperation of the customer, the carrier, and the equipment supplier.

The signals at the NI that are described in this standard are of two types:

− normal operating signals;

− maintenance signals.

This standard covers a 4-wire DS1 interface based on the various metallic digital facilities currently in use. Physical arrangements, electrical parameters, signal formats, and maintenance protocols are described.