AT&T cell phone users who like their current cell phone, but are forced to, or choose to, switch to a different wireless service carrier due to job relocation or poor service, may benefit from unlocking their existing cell phone. It doesn't make sense to buy a new phone when switching cell phone service providers if you're perfectly happy with the phone you have. Here is how to go about unlocking your existing AT&T phone.
Determine if your AT&T cell phone is CMDA or GSM. CMDA phones cannot be unlocked, while GSM phones can. The difference is in the SIM card. GSM phones use SIM cards to connect to the AT&T phone network while CMDA phones don't have SIM cards and the connection is 'hardwired' into the phone itself. By unlocking a phone, all you have to do is switch the SIM card to change service. You can see why it's tough (if not impossible) to unlock CMDA phones.
Call AT&T. The best and most accurate way to unlock your AT&T cell phone is to call your service provider. Keep in mind, however, that if you are under contract with the cell phone provider, they may not want to unlock your phone. You should wait until the contract expires to switch the service.
Look for unlock codes on the internet. If you are unable to persuade AT&T to unlock your phone, you can find unlock codes on the internet. Most websites that provide unlock codes charge a fee ranging from $9.99 and up. There are, however, a few sites that provide free unlock codes, such as Unlockitfree.com and Nokiafree.org for Nokia phones.
Purchase the unlock code for AT&T/Cingular Sony Ericsson phones. If you wish to unlock one of the Sony Ericsson cell phone models, the unlock code is available on Amazon.com. Be aware, however, this code only unlocks models W580i, W760a, C905a and W3501.
While unlock codes purchased over the internet usually work, they don’t work 100% of the time. Be sure to do your due diligence before purchasing an unlock code.
Review the terms of your contract before unlocking your AT&T cell phone.