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.

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 ...

I’ve been asked for my iPhone’s SIM number. How do I find it? How to find the SIM number on your iPhone: What is a SIM number? Your iPhone’s SIM number is technically called the ICCID, which stands ...

These two ways of connecting your phone to a cellular network are very different. We tell you about each and how you can switch from one to another.

If you’ve bought an iPad with 4G/cellular capabilities (we discuss whether that’s a good idea in our 2015 iPad buying guide) or a new iPhone, you need to buy and install a SIM card. Here, we explain ...