This Recommendation describes a signalling interface between an International Switching Centre (ISC) and a Digital Circuit Multiplication Equipment (DCME) with a built in device controller that allows a per call control of various functions in the DCME in real time. It is based on the interface described in ITU-T Q.50 [1]. In addition to the functions described in [1] that can be controlled by the switch, the compression/decompression function in the DCME can also be controlled.

The DCME is of type 2 (see ITU-T Q.50 [1]).

This interface is supported in E1-networks.

The signalling interface defined in this Recommendation assumes a fixed relationship between the circuits of the ISC and the DCME.

While this Recommendation is intended for use on international networks, the information defined here may be used within national networks.