What is a SIM card used for? A SIM card, or a subscriber identity module/subscriber identification module, is a tiny memory card that contains unique information and is linked to a particular network ...

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.

You'll need your AT&T Wireless transfer PIN to keep your old number when switching from AT&T to another carrier. You don't need this number when you change your phone number with AT&T. This guide ...

So you're in a pinch, and you need to swap out the SIM card or install a microSD in your Android device, but you can't find the nifty little ejector tool that came in the device's retail box. Fret not ...