MULTI-MODE MOBILE STATION SUPPORTING MULTIPLE CELLULAR TELEPHONE SYSTEM OPERATION WITH LIMITED SUBSCRIBER IDENTITY MODULE CARD

摘要

A multi-mode mobile station receives a subscriber identity module (SIM) card storing at least certain communications standard required subscription information that is common to a plurality of types of cellular telecommunications systems. The mobile station also includes an internal memory for storing communications standard required subscription information unique to each type of cellular telecommunications systems for which mobile station operations are supported. If a certain type of cellular telecommunications system is selected for mobile station operation, and the inserted SIM card fails to include the necessary communications standard required subscription information for that type of system, the common information is extracted from the SIM card and used in combination with the internal memory stored unique information specific to the selected type of system in effectuating mobile station operation.