A SIM card, or subscriber identity module, is a small card in your cellphone that lets you place phone calls, send text messages, and more.

Sareena was a senior editor for CNET covering the mobile beat, including device reviews. She is a seasoned multimedia journalist with more than a decade's worth of experience producing stories for ...

To unlock your iPhone from its carrier, you'll likely need to contact your carrier directly to cancel your contract.

Many smartphone users upgrade their devices to a newer device (in India), and they tend to face SIM card issues at times after switching to a new device. This is because, if you do not activate a few ...