While most people seem to manage just fine with a single SIM card in their smartphone, some -- especially travelers, who can save money by fitting a local SIM card into their handset -- love the ...

The subscriber identity module -- SIM -- contains the information used to connect to your wireless carrier's network from your iPhone 4. If you are planning to resell your company's iPhones, you ...

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 ...

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.

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.