A headset system (10) comprising a headset unit (1) and a detachable wearing device (4). The headset unit (1) comprises a microphone arm (3), which is movable between a compact position and an extended position. A proximity sensor (29; 33) in the headset unit (1) detects whether the microphone arm (3) is in the compact position or the extended position. The headset unit (1) and the wearing device (4) are adapted to be movably attached to each other, so that the headset unit (1) can be moved between a use position and a rest position. The proximity sensor (29; 33) detects, when the headset unit (1) is moved into the rest position.