21.1113GPPRelease 17TSUSIM and IC card requirements
The UICC shall be either a removable hardware module or a non-removable separate hardware module embedded in the ME. The USIM on a UICC shall contain an identity which unambiguously identifies a subscriber.
For access to 3G services, a UICC containing a valid USIM shall be present at all times, other than for emergency calls.
The specifications shall support the security requirements as defined in 3GPP TS 33.102 .
The USIM shall provide storage for subscription and subscriber related information.
The UICC/USIM may also contain applications which use the features defined in the USIM Application Toolkit specification 3GPP TS 31.111 .