ITU-T P.381 (03/2023)

Table of Contents
1 Scope
2 References
3 Definitions
3.1 Terms defined elsewhere
3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 General description
6 Physical characteristics
6.1 General rules
6.2 Pin assignments
7 Terminal electrical interface specification
7.1 Communication mode (terminal)
7.2 Multimedia playback mode (terminal)
8 Headset specification
8.1 Communication mode (headset) for the communication mode
8.2 Multimedia playback mode (headset)
9 Function requirements for terminals with the universal headset interface
Annex A – Interpolation method for diffuse-field correction
Annex B – Recording procedure using a representative headset
Appendix I – Audio connectivity for sockets with four contact points
I.1 2.5 mm diameter plug connector with four poles
I.2 2.5 mm diameter socket connector with four contact points
I.3 3.5 mm diameter plug connector with four poles
I.4 3.5 mm diameter socket connector with four contact points
Appendix II – Audio connectivity for sockets with four contact points (optional dimensions to accommodate terminal designs with curved edges)
Appendix III – Audio connectivity for sockets with three contact points
III.1 2.5 mm diameter plug connector with three poles
III.2 2.5 mm diameter socket connector with three contact points
III.3 3.5 mm diameter plug connector with three poles
III.4 3.5 mm diameter socket connector with three contact points
Appendix IV – Other considerations
IV.1 Filter recommendation
IV.2 Electrostatic discharge
IV.3 Microphone basics – background
IV.4 Vcc voltage for microphone bias
IV.5 DC resistance of microphone
Bibliography