SIM card

Rare card · No. 58426

A SIM card or SIM (subscriber identity module) is a type of integrated circuit, often in the form of a smart card. They are intended to securely store an international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephone devices (such as mobile phones, tablets, and laptops). SIMs are also able to run apps and to store arbitrary information like address book contact information, and may be protected using a PIN code to prevent unauthorized use. These SIM cards are typically used on GSM phones; CDMA phones historically did not use SIM cards, though the Removable User Identity Module (R-UIM) format was also used in certain CDMA devices. SIM cards are also used in satellite phones, smart watches, computers, or cameras. The first SIM cards were the size of credit and bank cards; sizes were reduced several times over the years, usually keeping electrical contacts the same, to fit smaller-sized devices. SIMs are...

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