http://pinouts.ru/PDA/htc_extUSB_pinout.shtml
Pin
Number Pin
Name Description
(may be empty)
1 USB VCC +5v
2 USB Data -
3 USB Data +
4 N / C
5 USB GND
6 Left Audio +
7 Sense Labeled "AG" on headset board
8 Audio - (GND) Labeled "CK" on headset board
9 Switch (Talk) Labeled "OT" on headset board
10 Right Audio +
11 Mic +
12 Chassis Ground (GND)