It has a feature to lock the
sim card, or the keypad, or the phone. My son just locked the phone - so i can't get past it asking for my code at power-on.
It is also At&T (written on the bottom of the phone) - if that helps.
We have SunCom service that was just switched over via a
sim card change and the unlock procedure (which is different from the 'phonelock'). thanks!