Prepaid card with integrated circuit and method for its control

摘要

Prepaid card, used in public telephones, with an integrated circuit which is capable of preventing increasing the usable amount of money and in the process of minimising the capacity of its memory. The prepaid card with an integrated circuit is controlled in that an input-output stage of the card is compelled to receive a new usable amount of money and an instruction to communicate from a public telephone, in that it is determined whether the instruction to communicate which is received from the input-output stage is a command to update the usable amount of money stored in a memory of the card, in that a comparator, with which the card is equipped, is compelled to compare the new usable amount of money with the usable amount of money which is stored in the memory, and in that an updating of the usable amount of money which is stored in the memory is controlled on the basis of the result of the comparison.