IM Services Identity Module (ISIM)

IM Services Identity Module (ISIM) is an application which resides on a mobile devices SIM card (UICC). It performs security procedures such as authenticating the network, and contains user identity and security keys used to encrypt the information transmitted over-the-air.

The ISIM application can co-exist with SIM and USIM on the same UICC making it possible to use the same smartcard in both GSM networks and earlier releases of UMTS.

References for the glossary can be viewed by clicking here.