Connecting wired stereo headset
The headset receptacle is a 3.5mm audio socket with 4 poles. The poles are arranged in a way allowing for standard unmodified stereo headphones to be used.
- 1 (tip) left HP output
- 2 right HP output
- 3 GND
- 4 (sleeve) microphone
AC100 can use a regular electret microphone connected to the 4th pin.
NB: some noname 4-pole jack i bought for a DIY adapter was impossible to insert before filing its tip.
This arrangement is compatible with the numerous iPhone headsets and is not compatible (without hardware mods) with the scheme used by Nokia.