ITU-T Recommendations

This 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 Recommendations G.711 [3] (PCM at both 64 kbit/s and 56 kbit/s) and G.726 [12] (ADPCM 32 kbit/s).It gives recommended values or masks for the following parameters: loudness ratings, sensitivity frequency response, harmonic distortion, out-of-band signals, terminal coupling loss, stability loss and delay.Annex A proposes recommended test methods, including the test conditions.The electrical interface specifications are referred to Recommendation P.310.