A CDMA subscriber identity module (CSIM) is an application to support CDMA2000 phones that runs on a UICC, with a file structure derived from the R-UIM card. By porting the application to the UICC (Universal Integrated Circuit Card), a card with CSIM, SIM, and USIM can operate with all major cellular technologies worldwide. The CSIM application allows users to change phones by simply removing the smart card from one mobile phone and inserting it into another mobile phone or broadband telephony device supporting the CDMA2000 radio interface.[1][2]