Keypad lock

To prevent accidental keypresses, select Menu, and press * within 3.5 seconds to lock the keypad.
To unlock the keypad, select Unlock, and press * within 1.5 seconds. If the security keyguard is on, enter the security code when requested.
To set the keypad to lock automatically after a preset time when the phone is in the standby mode, select Menu > Settings > Phone > Automatic keyguard > On.
To answer a call when the keypad is locked, press the call key. When you end or reject the call, the keypad locks automatically.
When the device or keypad is locked, calls may be possible to the official emergency number programmed into your device.