Switching the microphone to mute
When a call is active, the microphone can be muted.
1. "Telephone".
2. "Active calls".
3. 
"Microphone mute"
A microphone that has been switched to mute is automatically reactivated:
▷ When a new connection is established.
▷ When switching between call parties.
See also:
1982: the second generation - four-door, Convertible, Touring and BMW M3,
plus the first diesel engine for the sports sedan
The new BMW 3-Series oozed progress and variety out of every pore, as its
fresh new design, optimised aerodynamics, improved space and comfort, higher
output and additional body and engine variant ...
Switching off
The system can be deactivated as follows:
▷ Press the button.
▷ Switch off the ignition. ...
General information
The following functions are available:
▷ Use of a mobile phone as a telephone.
▷ Use of a mobile phone as an additional telephone.
▷ Use of a mobile phone as an audio source.
...