Editing Universal integrated circuit card (section)

== 2G versus 3G ==

In 2G networks, the SIM card and SIM application were bound together, so that "SIM card" could mean the physical card, or any physical card with the SIM application.

In a [[GSM]] network, the UICC contains a SIM application and in a [[UMTS]] network, it contains a [[SIM card|USIM]] application. A UICC may contain several applications, making it possible for the same smart card to give access to both GSM and UMTS networks, and also provide storage of a phone book and other applications. It is also possible to access a GSM network using a USIM application and it is possible to access UMTS networks using a SIM application with mobile terminals prepared for this. With the UMTS release 5 a new application, the IP multimedia Services Identity Module (ISIM) is required for services in the [[IP Multimedia Subsystem|IMS]]. The telephone book is a separate application and not part of either subscriber identity module.

In a [[cdmaOne]]/[[CDMA2000]] ("CDMA") network, the UICC contains a [[CDMA subscriber identity module|CSIM]] application, in addition to 3GPP USIM and SIM applications.  A card with all 3 features is called a removable user identity card, or  [[RUIM|R-UIM]].  Thus, the R-UIM card can be inserted into CDMA, GSM, or UMTS handsets, and will work in all three cases.

In 3G networks, it is a mistake to speak of a USIM, CSIM, or SIM card, as all three are applications running on a UICC card.