Prepaid-mode card usage method

摘要

The mobile telephone prepayment card has data and program memories, a control unit and contacts. The data memory (12) has N directories each directory containing a file ((ACM)i) of units consumed and a file ((ACMMax)i) of the maximum available units. Access to the units in each directory is gained by using a code (CODEi) which is purchased when the units used in a previous directory exceeds the maximum available