Help > Telephoning > Call
Call
A Call 
Shows information about the call such as phone number/contact with profile picture.
B Detail bar 
Displays additional information about the call such as call time, call paths and groups involved.
Opens details.
Closes details.
C Action bar 
*Note: Swiping up within the action bar reveals hidden symbols.
Ends the conversation.
Turns on the speaker.
Turns the speaker off again.
Starts a new call (query call).
Pauses the call (holds).
Resumes the call (reconnects).
Mutes the microphone (mute).
Turns the microphone back on (unmutes it).
Initiates transfer of the call partner (transfer without announcement).
Sends DTMF signals (digits in the ring).
*Further help under Call and transfer