Activate your iPhone back to AT&T if the SIM card you insert after you install blackra1n onto the device doesn't work properly. Blackra1n is a third-party program that "jailbreaks" SIM-bearing ...

We outline four simple methods to set up an iPhone so that it can be used without a SIM card, by a child or someone who doesn't have a mobile contract. And we show how to activate without a Wi-Fi ...

If you're a new Metro by T-Mobile customer who bought a SIM card online or in a retail store, you'll need to activate it, and we're here to help.

Activating a new Sim card isn’t always as straight forward as it sounds. This handy guide will take you though the process for the biggest networks.