| 摘要 |
In order to avoid attempted fraud, the reader is provided with a detector for detecting a conductor wire disposed fraudulently in the insertion passage. The detector comprises a conducting plate (50) disposed across the passage. The plate (50) is fed with A.C. (62). When a fraudulent conductor wire (46) is connected to one of the contact blades (26) of the read head (28), the detector circuit is looped by capacitive coupling between the wire (46) and the plate (50).
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