scope:

This standard describes the electrical interface between a carrier and customer installation (CI), referred to as the network interface (NI), for synchronous digital data at 2.4, 4.8, 9.6, 19.2, 38.4, 56, and 64 kbit/s. This standard applies primarily to dedicated services but may also be applied to other services. It establishes requirements at the NI necessary for compatible operation between the carrier and the Cl.

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.

Purpose

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 problem should be resolved through the cooperation of the user, the carrier, and the equipment supplier.

The signals at the NI that are described herein are of two types:

1. Normal operating signals; and

2. Maintenance signals.

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

This standard covers the 4-wire digital signal customer service (DS-CS) interface based on the various electrical digital facilities currently in use as shown in Figure 1. Physical arrangements, electrical parameters, signal formats, and maintenance protocols are described.