Summary

Recommendation ITU‑T P.381 specifies critical physical and electrical-acoustical characteristics for the universal headset interface and provides corresponding test methods. Both 3.5 mm and 2.5 mm diameter headset or headphone (HP) interfaces have been widely used in digital mobile terminals in recent years. Nowadays, the consumer is free to choose either the headset or HP originally provided by the terminal manufacturer or others that are offered separately. However, the quality of service or experience perceived by users is influenced by both the electrical performance of the interface and the compatibility between the terminal and the connected headset or HP.