The Phone Lock feature, helps prevent unauthorized use of the device by disabling outbound data and voice calls. The device will still be able to receive phone calls and place emergency calls to 9-1-1.
With the handset open and from the main screen, navigate: MENU > Settings & Tools > Phone Settings.
Utilize the 5-way navigation pad to highlight then press the center/OK button to select.
Enter the Security Code.
The default code is the last 4 digits of the phone number.
Select Lock Phone Now.
To enable / disable the phone lock when the device is powered on: