| 摘要 |
A plurality of resistive elements, each adapted to exhibit the Hall effect, are arranged in a plane. A magnetic card with a plurality of portions magnetized along lines perpendicular to the card faces is adapted to be placed adjacent such plane with each magnetized portion aligned with a respective element. From each element a voltage is developed which represents the polarity of the adjacent end of the magnetized card portion aligned therewith, and via a program network such voltages are applied to a multiplexer. A keyboard is provided with keys or pushbuttons to be operated by a customer in a predetermined sequence. Via a counter and decoder, successive key operations enable different portions of the multiplexer to provide successive BCD outputs therefrom, and simultaneously a converter establishes a BCD output corresponding to the number or location of each key that is operated. The pairs of BCD signals are applied to a comparator which is connected to a memory unit. A clock pulse established upon each key operation is also applied to the memory unit, and an output for the memory unit is established coincidentally with the occurrence of the clock pulse generated upon operation of the last key in the predetermined sequence. The output of the memory unit is true if the successive comparisons matched, whereupon a lamp is operated to signify that the card is good. The memory unit output is false if all comparisons did not match, whereupon a lamp is operated that signifies the card is bad.
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