AT&T is the exclusive cellular provider for the GSM-version of the iPhone in the United States. This phone operates on AT&T's GMS network. Verizon offers a version of the iPhone that operates on a CDMA network, which is not compatible with GMS technology. AT&T's iPhone requires a Subscriber Identity Module, commonly known as a SIM card, to function. When you initially insert the SIM card into your iPhone, you will be prompted to enter the SIM passcode. If you enter this code incorrectly five times, the SIM card will lock and you will be required to enter a special PIN unlock code, known as a "PUK" code, to unlock the iPhone.
Instructions
1. Open a Web browser and navigate to AT&T's myWireless homepage.
2. Enter your AT&T Wireless phone number and password, then click the "Log In" button.
3. Click "My Services" and select the "My Phone/Device" link.
4. Click the "Unblock SIM Card" option. A Web page will appear displaying your PIN unlock code.
5. Type in the PUK code using the iPhone's virtual keypad. Assuming you enter the code properly, it will unlock the SIM card and restore functionality to your iPhone.
Tags: unlock code, your iPhone