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 ...

Once you’ve activated your iPhone with your carrier, it should continue to work on the cellular network without any problems as long as you’re within range of a tower. Nevertheless, the vagaries of ...

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 ...

Do you get the error message “No SIM Card Detected” or “No SIM Card Installed” after inserting a SIM card into your phone? This problem often occurs when you ...

So you’ve chosen Ultra Mobile as your carrier. Great choice! But before you start enjoying those international calling features or high-speed data, you need to install your SIM card. Don’t worry; ...

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 ...

While most people manage quite well with a single SIM card, if you want better demarcation between your work and home life, or you want to make roaming with multiple SIM cards easier, then having the ...

Eli covered the latest in the ever-changing worlds of telecom, streaming and sports. He previously worked as a technology reporter at USA Today. With eSIMs, you'll still be able to take full advantage ...