Silence All
There may be times when you need to silence your phone entirely. The phone’s Silence All option allows you to mute all sounds without turning your phone off.
To activate Silence All:
With the phone open, press and hold the volume key down in standby mode. (The screen will display “Silence All.”)
To deactivate Silence All:
With the phone open, press the volume key up repeatedly to select a desired volume level.