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 ...

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 ...

Find out how to trim your own micro-SIM card for use in phones that require this new format. Sharon Profis Former Vice President of Content, CNET Studios As vice president of CNET Studios, Sharon led ...

The SIM cards that fit into those tiny slots in your cell phone and tell your cellular network to whom your calls are to be charged come in four different sizes. With the only real difference between ...