Method and apparatus for evaluating units stored on credit cards

摘要

A method for the evaluation of used fee units of a card owner and of a central evaluation location (uP) stored on credit cards (KK) for automatic vendors. In the present invention an evaluation method which prevents manipulations at the credit card is used. This results in that the used fee units are stored in at least one counter (RZ1, RZ2) arranged on the credit card (KK) whose current reading is called in by the central evaluation location (uP) at intervals unknown to the card owner, particularly at randomly oriented intervals, and, subsequently is compared in the evaluation location (uP) to the most recently called-in counter reading. The account of the card owner is charged with the difference between the old and the new fee units.