Sharp AN-SS1 Operation Manual page 16

Listening to Bluetooth enabled devices (continued)
Call Functions (continued)
Function
Mute a call
Unmute a Call
Note:
Remote control of call functions with the Speaker may not be applicable
in some mobile devices/applications.
While on a call, press and hold the Play/Pause
Button for 1 second.
While on a call, press the Jog Button in the
middle.
EN-15
What to do