1. Find "SIM security"
Press the Navigation key.
Select Settings.
Select Security.
Select SIM security.
2. Turn use of PIN on or off
Select PIN lock to turn the function on or off.
Key in your PIN and press the Navigation key.
If an incorrect PIN is entered three times in a row, your SIM will be blocked. To unblock your SIM, you'll need to key in your PUK. The PUK can be obtained by contacting customer services. Please note: If you key in the wrong PUK ten times in a row, your SIM will be blocked permanently. In this case, you need a new SIM from Vodafone.
3. Return to the home screen
Press Disconnect repeatedly to return to the home screen.