Editing SIM card (section)

{{Short description|Integrated circuit card for mobile devices}}
{{Redirect|Micro-SIM|the company|MicroSim Corporation}}
[[file:SIM-Karte von Telefónica O2 Europe - Standard und Micro.jpg|thumb|A typical SIM card (mini-SIM with micro-SIM cutout)]]A '''SIM card''' or '''SIM''' ('''subscriber identity module''') is an [[integrated circuit]] (IC) 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 phone]]s, [[Tablet computer|tablets]], and [[laptop]]s). SIMs are also able to store [[address book]] contacts information,<ref name=":4" /> and may be protected using a [[Personal identification number|PIN code]] to prevent unauthorized use.

SIMs are always used on [[GSM]] phones; for [[Code-division multiple access|CDMA]] phones, they are needed only for [[LTE (telecommunication)|LTE]]-capable handsets. SIM cards are also used in various [[satellite phone]]s, smart watches, computers, or cameras.<ref name="ihs" /> The first SIM cards were the size of [[Bank card|credit and bank cards]]; sizes were reduced several times over the years, usually keeping electrical contacts the same, to fit smaller-sized devices.<ref name="sim-evolution">{{cite web |author1=GSMA Intelligence |title=Understanding SIM evolution |url=https://data.gsmaintelligence.com/api-web/v2/research-file-download?id=18809300&file=understanding-sim-evolution-1482139874006.pdf |url-status=live |archive-url=https://web.archive.org/web/20230320082628/https://data.gsmaintelligence.com/api-web/v2/research-file-download?id=18809300&file=understanding-sim-evolution-1482139874006.pdf |archive-date=20 March 2023 |access-date=2023-05-31 |website=GSMA Intelligence |publisher=GSMA}}</ref> SIMs are transferable between different mobile devices by removing the card itself. 

Technically, the actual physical card is known as a [[universal integrated circuit card]] (UICC); this [[smart card]] is usually made of [[Polyvinyl chloride|PVC]] with embedded contacts and [[semiconductor]]s, with the SIM as its primary component. In practice the term "SIM card" is still used to refer to the entire unit and not simply the IC. A SIM contains a unique serial number, integrated circuit card identification (ICCID), international mobile subscriber identity (IMSI) number, security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to, and four passwords: a [[personal identification number]] (PIN) for ordinary use, and a [[personal unblocking key]] (PUK) for PIN unlocking as well as a second pair (called PIN2 and PUK2 respectively) which are used for managing [[Fixed Dialing Number|fixed dialing number]] and some other functionality.<ref>{{cite web |title=Calling Features on Your Samsung Galaxy Phone |url=https://www.samsung.com/us/support/answer/ANS00086742/ |publisher=[[Samsung]] |at=Limit Calling to Specific Numbers |access-date=2022-04-19 }}</ref><ref>{{cite web|url=https://www.nokia.com/phones/en_us/support/nokia-6-2-user-guide/access-codes|title=Access codes|publisher=[[Nokia]]}}</ref> In Europe, the serial SIM number (SSN) is also sometimes accompanied by an [[International Article Number|international article number]] (IAN) or a [[International Article Number|European article number]] (EAN) required when registering online for the subscription of a prepaid card.[[file:Tf sim both sides.png|thumb|A [[TracFone Wireless]] SIM card has no distinctive carrier markings and is only marked as a "SIM card".]]As of 2020, [[eSIM]] is superseding physical SIM cards in some domains, including cellular telephony. eSIM uses a software-based SIM embedded into an irremovable [[eUICC]].