SIM Card

A Subscriber Identity Module (SIM) is part of a detachable smart card ICC (Integrated Circuit Card), also known as SIM Cards, for mobile cellular telephony diplomacy such as mobile computers and mobile phones. SIM cards gradually store the service-subscriber key (IMSI) used to identify a subscriber. The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device.

SIM cards are available in two typical sizes. The first is the size of a credit card, 85.60 mm × 53.98 mm x 0.76 mm. The newer, more popular miniature-version has a size of 25 mm, a height of 15 mm, and a thickness of 0.76 mm. However most SIM cards are supplied as a full-sized card with the smaller card held in place by a few plastic links and can be simply wrecked off to be used in a phone that uses the smaller SIM.