APN Settings for an AT&T Unlocked Phoneby Robert Schrader
If you unlock an AT&T cellphone, you are able to use the device not only with another carrier's SIM card for call and text service, but also potentially with another carrier's cellular data access point name, or "APN." Once you have APN credentials for a cellular data network, use that network to surf the Internet from your unlocked AT&T cellphone.
What is an APN?
An Access Point Name or APN allows you to remotely access a carrier's cellular data network. One common reason for using an APN is if you're using a cellular data network other than the one offered by the carrier to which your phone is assigned. The only legal way to obtain APN credentials is directly from a carrier and upon subscription to its service plan. Otherwise, you are essentially hacking that carrier's network.
Whether you've switched the phone to another carrier and want to use it on the AT&T data network or are still using it with AT&T and want to use another carrier's network, the first piece of information you need to adjust the APN is the APN network name. The network name usually contains the carrier's name, but may be different depending on your geographical area. Ask a carrier representative for the APN network name appropriate to your region.
APN Username and Password
After you know the APN Network name, the next two pieces of information you need are a username and password, just as if you were logging into an email account or a social network. It's important that you enter these credentials exactly as the carrier gives them to you, or connection to its data network via an APN will fail.
Not all phones are capable of accepting manual APN entries. For example, if you want to change APN settings for an iPhone, you must "jailbreak" the device, an unauthorized procedure which also voids its manufacturer's warranty. A simple way to access a carrier's cellular data network without adjusting the APN is simply to purchase and activate a SIM card from that carrier, then select a monthly cellular data package alongside your voice and text plan.