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 ...

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 ...

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 ...