Subscriber Identity Module

A Subscriber Identity Module (SIM) is a small card that is put into a cell phone or similar device. It stores information like your phone number, carrier, and other data that helps connect you to the cell phone network. The SIM card is like an ID card – it helps the cell phone network know who you are and which services you have access to. It makes it easier for you to switch between different cell phone carriers without needing to buy a new device.