Aastra Telecom 55i IP Phone - Manual (Page 91)

Model 55i IP Phone User Guide 85
Making Calls
Mute
Press the button at any time to mute handset, headset or handsfree.
The speaker light will flash slowly and you can hear the caller, but they
cannot hear you. To switch mute on or off, press .
Note: If you place a muted call on hold, the phone automatically takes the call off
mute when you reconnect to the call.
IP Phone UI