Abstract: A card with a magnetic stripe when fed into a card reader can be illegally read by a read head unobtrusively attached to the outside of the card reader adjacent to the slot into which the card is fed. To defeat this illegal reading, movement of a card through the read head is interrupted thereby making it difficult for the illegal read head to read the stripe. This interruption occurs at the point where the proper read head inside the card reader is not reading the magnetic stripe. The interruption can be a brief stop or a brief reversal in direction. The interruption occurs once while the card is being fed into the card reader and once when the card is being fed out of the card reader.

Abstract: A card with a magnetic stripe when fed into a card reader can be illegally read by a read head unobtrusively attached to the outside of the card reader adjacent to the slot into which the card is fed. To defeat this illegal reading, movement of a card through the read head is interrupted thereby making it difficult for the illegal read head to read the stripe. This interruption occurs at the point where the proper read head inside the card reader is not reading the magnetic stripe. The interruption can be a brief stop or a brief reversal in direction. The interruption occurs once while the card is being fed into the card reader and once when the card is being fed out of the card reader.

Abstract: A method for judging coercive force of a magnetic card to judge coercive force of a magnetic card to be used. According to the method for judging coercive force of a magnetic card for reproducing or recording magnetic information formed on a low coercive force card or a high coercive force card inserted from a card slot by a magnetic head, after erasing data of an inserted card by an electric current capable of erasing data of only a low coercive force card (step S32), the data of the card is reproduced (step S33), the inserted card is judged as the low coercive force card (step S36) if the data has been destroyed (No at the step S34). Destruction of the data is judged based on the number of times of flux reversal of the reproduced data or by a fact that specific data (STX code) which should be recorded on a predetermined card is not recognized.

Abstract: A card with a magnetic stripe when fed into a card reader can be illegally read by a read head unobtrusively attached to the outside of the card reader adjacent to the slot into which the card is fed. To defeat this illegal reading, movement of a card through the read head is interrupted thereby making it difficult for the illegal read head to read the stripe. This interruption occurs at the point where the proper read head inside the card reader is not reading the magnetic stripe. The interruption can be a brief stop or a brief reversal in direction. The interruption occurs once while the card is being fed into the card reader and once when the card is being fed out of the card reader.