This ITU-T Recommendation provides audio performance requirements for loudspeaking and hands-free telephony terminals using, in the telephone band (300-3400 Hz), the waveform encoding according to ITU-T Recommendations G.711 (PCM at both 64 kbit/s and 56 kbit/s) and G.726 (ADPCM 32 kbit/s).

This ITU-T Recommendation does not deal with audio performance requirements for digital telephones using coding schemes other than waveform encoding and at bit-rates lower than 32 kbit/s.