Samsung SGH-I747MBAATT - Manual (Page 123)

Changing Your Settings 115
SIM card lock
Prevent another user from using your SIM card to make
unauthorized calls or from accessing information stored on
your SIM card by protecting the information using a PIN code.
When enabled, your phone will ask for a PIN number each
time you use the phone. Using this option you can also
change your SIM PIN number.
1. From the More menu, tap Security ➔ Set up SIM card
lock.
2. Tap Lock SIM card, enter your SIM PIN code, then tap
OK.
3. To change your SIM card PIN code, tap Change SIM PIN.
4. Enter your old SIM PIN code and tap OK.
5. Enter your new SIM PIN code and tap OK.
6. Re-type your new SIM PIN code and tap OK.
Forgotten SIM PIN code
If you enter the wrong SIM PIN more than 3 times, you will
need to contact your AT&T Customer Service Representative
to get the PUK code for your device.
1. Each time you enter a wrong SIM PIN code the phone
will display how many attempts you have remaining.
2. After the third incorrect attempt, the Type PUK and new
PIN code screen displays and your SIM card is locked.
3. Enter the PUK code that you received from your AT&T
Customer Service Representative in the PUK code field.
4. Enter a new PIN code in the New PIN code field and tap
OK.
5. Enter the new PIN code again in the Confirm PIN code
field and tap OK.
Note: You must enable the Lock SIM card option before
you can change your SIM PIN code.
Note: While your SIM card is locked, you will still be
able to make Emergency calls, if necessary.