The evolution towards interactive multimedia applications and the implementation of new signal processing devices both in terminals and communication networks means that a number of sophisticated signal processing algorithms will be deployed for echo control, noise reduction, level control, voice activity detection, speech coding, speech recognition and voice-band traffic technologies. These may interact with each one another in ways that could potentially affect the quality of speech and voice-band signals.

The purpose of this Recommendation is to describe interaction aspects and to provide requirements for the interoperability of Speech Processing Network Equipment (SPNE), between different SPNE, between SPNE and terminals and between SPNE and other devices in the General Switched Telephone Network including mobile networks.