| 摘要 |
PURPOSE:To make it possible to discriminate a defective card by a terminal side, as well, by not only reducing the number of digits of card No. and storing it, but also separately storing card No. of all the digits of a part of defective cards. CONSTITUTION:A credit card 1 is put into a reader 3 and card No. of m digits is stored in a memory of the processing unit 5 as it is. The card No. is converted from m digits to n digits (m>n) in a converter 11. No. of n digits is collated with all defective card Nos. of n digits which have been written in a memory 12, and in case both do not accord, it is displayed as valid in an indicator 6. In case they have accorded, No. of m digits of the memory of the processing unit 5 is collated with all the Nos. of m digits which have been written in a memory 13, and when both Nos. of m digits have accorded, its card is regarded as invalid, and is displayed in the indicator. In case they have not accorded, it is referred to the central processing unit. As a result of the foregoing, frequency of use of a communication circuit can be reduced. |
