Let’s say you spent your vacation abroad a couple of years ago. Being thrifty, you removed your U.S. SIM card from your unlocked iPhone 4 and inserted a SIM card from a carrier in the country you were ...

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 ...

A SIM card, or subscriber identity module card, is essential component of any phone. It connects your device to a cellular network and stores vital information, including your phone number. Many ...

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 ...

Running a business requires you to stay connected to the outside world, and one way to do that is by having a smartphone. IPhones are often used for this purpose, but they are useless if you can't get ...

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 ...

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 ...

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 ...