SIM Card Definition
When it comes to “SIM cards”, it is often difficult to know what it really refers to. This page aims at summing up the realities behind the “SIM cards” designation.
SIM (Subscriber Identity Module) is an integrated circuit which securely stores the service-subscriber key (IMSI) to identify a subscriber on mobile telephone device. The SIM is a removable card which can be transferred from one device to another.