Samsung SCH-3550 - Manual (Page 55)

-G[IWCTF
To avoid accidental key presses, you can enable the KeyGuard
feature. However, you’ll still be able to receive incoming calls
and messages. This feature also prevents needless battery usage
because the phone does not respond to any keypresses and
turns off the backlight.
Note: If you have an incoming call, open the flip to answer it.
When you are done with the call, close the flip and KeyGuard is
automatically turned on.
To activate KeyGuard:
1. Press to display the Main Menu.
2. Press for KeyGuard. The keypad locks and
“KeyGuard” displays.
3. Press and hold to deactivate KeyGuard, or simply
open the flip to turn on the backlight and temporarily
disable KeyGuard.
Note: KeyGuard works only when the flip is closed.