METHOD FOR DECIDING VALIDITY OF MAGNETIC CARD AND RECORDING/REPRODUCING DEVICE FOR DECIDING VALIDITY OF MAGNETIC CARD

摘要

PURPOSE: To prevent illegal alteration of information recorded in a prescribed position of a magnetic track with high probability by collating whether or not the information is recorded based on an information amount at specific intervals. ;CONSTITUTION: Information are recorded respectively on the part L1 of the interval of the magnetic track 54 corresponding to the interval between the first magnetic bar code 51 and the second magnetic bar code 52 of a magnetic card 5 for the time Ta having the maximum value of a card transfer speed in a center in a first card similar to the magnetic card 5, the time Tb having the mean speed V of the transfer speed in the center in a second card, and the time Tc having the minimum value of the transfer speed in the center in a third card. At this time, the transfer distance of the magnetic card is shown by oblique line parts Sa, Sb, Sc, and L1 is the interval of the magnetic card 54 corresponding to the interval of the bar codes 51 and 52 and all parts become an equal area. However, the recorded information amount is in proportion to recording times Ta, Tb, Tc since a recording frequency is fixed. Thus, by comparing the recorded information amount, the cards A, B, C are identified.;COPYRIGHT: (C)1995,JPO