Find "Passcode Lock"
Choose one of the following options:
Turn on lock code, go to 2a.
Turn off lock code, go to 2b.
2a - Turn on lock code
Key in a lock code of your own choice.
Key in the same lock code again.
Press Immediately or the required interval.
Press Passcode Lock at the top of the display to return to the settings.
2b - Turn off lock code
Press the Home key to return to standby mode.