Sunday December 08, 2013

Why Do Cellphones Need a SIM Card?

If you have a smartphone, chances are extremely good that it has a SIM card inside to get you connected to your network of choice. Other than that, what do you actually know about the ubiquitous little SIM card you can’t do without?

Each SIM card has a unique identifier called the ICCID (Integrated Circuit Card Identifier), which is stored in the card and engraved upon it. The ICCID contains 3 numbers: an identifying number for the SIM card issuer, an identifying number for the individual account, and a parity digit that’s calculated from the other two numbers for extra security.