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 ...

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 ...

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; ...

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 ...