Funkwerk FC4 Operating Manual page 44

Open listening, switching the microphone off
At the end of the phone call, the handsfree talking loudspeaker is
switched off and the microphone is switched on again.
When you place your handset into the charger while a conversation
6 1 2
is going on, handsfree talking is activated provided this behaviour is
GB
activated at Menu > Setup > Phone settings > Phone behaviour >
Behaviour in charger.
44
FC4 / FC4 Ex (HS) connected with Mobility Server