<Table> <Tr> <Td> </Td> <Td> It has been suggested that Overlay SIM be merged into this article . (Discuss) Proposed since July 2017 . </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> It has been suggested that Overlay SIM be merged into this article . (Discuss) Proposed since July 2017 . </Td> </Tr> <P> A subscriber identity module or subscriber identification module (SIM) is an integrated circuit that is intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). It is also possible to store contact information on many SIM cards . SIM cards are always used on GSM phones; for CDMA phones, they are only needed for newer LTE - capable handsets . SIM cards can also be used in satellite phones, computers, or cameras . </P> <P> The SIM circuit is part of the function of a universal integrated circuit card (UICC) physical smart card, which is usually made of PVC with embedded contacts and semiconductors . "SIM cards" are transferable between different mobile devices . The first UICC smart cards were the size of credit and bank cards; sizes were reduced several times over the years, usually keeping electrical contacts the same, so that a larger card could be cut down to a smaller size . </P>

What does the s stand for in sim