scope:

This standard describes the metallic interface between a carrier and customer installation (CI), referred to as the network interface (NI), at the DS1 rate. It establishes requirements at the NI necessary for compatible operation between the carrier and the CI. Interfaces such as carrier-to-carrier, PBX-to-PBX, PBX-to-computer, and PBX-to local area network are not covered in this standard.

 NOTE: The user's attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights.

 By publication of this standard, no position is taken with respect to the validity of this claim or of any patent rights in connection therewith. The patent holder has, however, filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain such a license. Details may be obtained from the publisher.

 The requirements in this standard are for the purpose of establishing a functional and practical interface, and compliance with them 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 user, the carrier, and the equipment supplier.

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

 (1) Normal operating signals

 (2) Maintenance signals

Signals that appear as a result of the environment (e.g., induced voltages and currents, lightning hits, and like) are not covered.

This standard covers the 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.