Mobile Station
Subscriber Identity Module
n ISO compliant removable smart card, with limited storage and
computational functionality
n necessary for operation of mobile station, and involved in
location management, authentication, and ciphering
n one or more directory numbers per SIM, one or more SIMs per
subscriber
n SIM realizes model of “personal mobility” (e.g., the subscriber
is the focus of attention and it is he/she who is mobile)
Mobile Equipment
n only emergency calls allowed without SIM
n calls routed to SIM, not mobile equipment