AT&T 7406BIS - Manual (Page 44)

Mute ✓
Note: Use the Mute button in one of the following ways.
●
If your voice terminal has the Speakerphone feature, use the Mute button to turn off
the microphone associated with the built-in speakerphone or the handset.
●
If your voice terminal has the Speaker (listen-only) feature, the Mute button turns off
only the handset.
This feature has no effect on an external speakerphone.
To prevent other party 1 Press [ Mute ]
from hearing you
●
Red light goes on and other party cannot hear you
2 When you are ready to resume conversation with other
party, press [ Mute ] again
●
Red light goes off and other party can hear you again
Note: The Mute feature turns off automatically when
you hang up, or switch from the speakerphone to the
handset or from the handset to the speakerphone.