Introduction This document establishes the interface functions commands and application protocols required for operation of the Removable User Identity Module (R-UIM)@ when inserted into compatible Mobile Equipment (ME). It is an extension of Subscriber Identity Module (SIM)@ as specified in ETSI GSM 11.11 capabilities@ to enable operation in a TIA/EIA-136 environment. These requirements are expressed as additions to the current specification of the SIM; the composite R-UIM is comprised of the current SIM specification and this ancillary document.