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.

The sim card that exists inside your phone is what connects your phone to your specific cellular network. For most of us we might not even realize it’s there. When we get a new phone from our carrier, ...

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. I started my career with CNET all the way back in ...