| 摘要 |
PURPOSE:To obtain a true/false decision method of extremely high security by forming a recording medium in such a manner that at least the magnetic polarities of the edge part thereof represents a code for true/false decision, detecting the magnetic polarities thereof and collating the combination of said polarities with a correct combination. CONSTITUTION:A magnetic card 1 is provided with three pieces of magnetic recording tracks T1-T3 on the magnetic layer oriented in one direction and, for example, only the magnetic polarity in the edge part of the track T2 is inverted. An N-S-N or reverse combination is, therefore, obtd. if the polarity of the edge part is detected. Such polarity is utilized as the code for true/false decision of the magnetic card. If, for example, the magnetic card 1 is a prepaid card, the balance changes at every use and, therefore, the code for true/false decision is determined from said balance. The code for true/false decision is updated at every use. The falsification of the balance is thereby easily discovered even if such falsification is made.
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