The evolution towards interactive multimedia applications and 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 voiceband traffic technologies. These technologies may interact with one another and with the imperfections of transmission systems, such as delay and error bursts, to adversely affect the quality of speech and voiceband signals.

The purpose of this Recommendation is to clarify interaction aspects and to provide guidance to minimize the undesirable interactions of signal processing network equipment (SPNE), between different SPNE, between SPNE and terminals and between SPNE and transmission systems in telecommunication networks.