Defines the interface between the Subscriber Identity Module (SIM) and the Mobile Equipment (ME), and mandatory ME procedures, specifically for "SIM Application Toolkit" which is a set of commands and procedures for use during the network operation phase of GSM, in addition to those defined in GSM 11.11. This standard defines the commands, the application protocol, and the mandatory requirements on the SIM and ME for each procedure. This standard does not specify any aspects related to the administrative management phase nor any of the security algorithms which may be used. This Technical Specification defines an enhancement for GSM Phase 2+ of the SIM/ME interface for GSM Phase 2.