The aim of this Recommendation is to define test methods and requirements for subsystems of automotive narrowband and wideband speakerphone terminals and other speech services using the speakerphone's acoustic interface. This Recommendation covers the following:

– definition of subsystems based on different system architectures;

– performance requirements for subsystems;

– diagnostic information;

– guidance on component and subsystem optimization;

– coordination of subsystems;

– both narrowband and wideband systems;

– acoustic interface requirements for other speech services such as speech recognition and application prompt playback.

The methods, the analysis and the performance parameters described in this Recommendation are based on test signals and test procedures defined in [ITU-T P.501], [ITU-T P.502], [ITU-T P.340], [ITU-T P.1100], [ITU-T P.1110], [b-ETSI ES 202 739] and [b-ETSI ES 202 740].

Several performance classes are defined for each performance parameter instead of a single pass/fail criterion. This enables easier interpretation of the performance levels achieved and provides more flexibility in specifying the required performance level of a subsystem. Lower numbered classes have more stringent requirements and represent higher performance levels.

Note that all limits in this version of the Recommendation are considered provisional due to the lack of verification data. Furthermore, the interpretation of the performance classes deserves further study.