ITU-T P.310 PDF

This Recommendation deals with sending and receiving frequency response, loudness rating, noise, distortion, out-of-band signals, linearity, sidetone, echo and delay of narrow-band (300-3400 Hz) digital handset and headset telephones using "Waveform" encoding according to [ITU-T G.711] (PCM at both 64 and 56 kbit/s) and [ITU-T G.726] (ADPCM, 32 kbit/s). IP terminals and wireless headsets are not covered in this Recommendation.

The use of digital telephones using [ITU-T G.728] (LD-CELP, 16 kbit/s) and mobile/cordless telephones are under study.

Requirements applicable to low acoustic impedance transducers and digital telephone sets using non-linear techniques are under study.

The requirements listed in this Recommendation should also be used as the basis of requirements for other "waveform" encoding schemes.

The values given in this Recommendation should be used for developing specifications which will include assigning tolerances, etc.