APPARATUS AND METHOD FOR MAKING A CALL BY A PREPAID SUBSCRIBER IN A NON-CAMEL NETWORK

摘要

A SIM (201) within mobile device or terminal (202) is programmed with the list of Mobile Switching Centers (MSC)?/isitor Location Registers (VLRs) that cannot support CAMEL. The SIM (201) is programmed with a USSD Code (e.g. *BAL#) which is used for obtaining a balance inquiry from a prepaid system (205). When the subscriber is visiting in a non-CAMEL MSCs (203), a SIM application (201A) loaded in SIM (201) launches the USSD balance inquiry (e.g. *BAL#) while the call set up is on-going. The mobile device or terminal (202) communicates via the subscriber's HLR (204) to prepaid system (203) then returns the balance. This is an existing feature in many prepaid systems. The SIM application (201A) authorizes the call if the balance is above a certain threshold. As an extension, the SIM application (201A) can launch the USSD balance inquiry during the call at a regular interval and let the call continue if the balance is sufficient. If the balance goes below a threshold, the mobile device or terminal (202) through SIM application (201A) will tear down the call.