Samsung MM A880 Phone Manual page 57

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:
Press the volume key up repeatedly to select a desired
volume level.
Section 2B: Controlling Your Phone's Settings 49