5.6 Press the mute button to mute headset microphone. The mute indicator will be
ON. To Un-mute the headset microphone, press the mute button again.
Indicator will be OFF.
5.7 Connect an additional Headset
An additional headset can be connected to the supervisor port on the unit. It
has the same function as the default headset. Microphone mute switch for
supervisor is located on the bottom.