Our library system RFID anti-theft gate appears to be mulfunctioning, normal operation is such that if a tagged book is not checked out it sets off the alarm if a person walks past the gate with the book. The gate has stopped setting off the alarm whether a book has been checked in or out.

 

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We're not psychic. Without a lot more detail (make/model/schematic etc) of your system we'd only be offering guesses.