SummaryITU-T Recommendation P.313 provides audio performance requirements for portable digital cordless and mobile handsets, headset and speakerphone sets. The requirements apply to narrow-band systems (3.1 kHz) regardless of the coding algorithm used in the terminal. Associated test methods are also given. Requirements are specified for the major electro-acoustic performance parameters affecting audio quality, including sending and receiving levels, frequency responses, noise, sidetone, stability, echo path and delay. The requirements given in this Recommendation should ensure satisfactory service quality in a high percentage of installations under normal conditions. Changes over the previous version of this Recommendation (2004) are as follows: • Specifications for headset terminals have been added. These requirements are intended for mobile terminals which use headset. • Specifications for hands-free terminals are recommended for handheld and desktop speakerphone set, and those for car mounted hands-free terminals will be removed to a separate Recommendation. • The receiving masks for handset to use Type 3.2, Type 3.3 and Type 3.4 artificial ears are also recommended. Testing methods for handsets have been updated to use test signals defined in ITU‑T Recommendations P.50 and P.501. |