Why do I get “ unknown Card Format” errors when I swipe my card?

·         Ensure that the board’s signal ground is stable;

·         Ensure that the DATA0 and DATA1 is properly connected;

·         Ensure that the card reader cable is shielded and properly grounded to a separate communication ground away from the board’s signal ground point;

·         Ensure that the card reader is fully functional;

·         Ensure that the power supply for the card reader is measured at 12 vdc ( referenced the “ common” signal ground when connected and not below 12 Vdc;

·         Ensure that the Card operates at the same frequency as the card reader;

·         Ensure that the card reader’s cable is less than 350-450 ft in length; and

·         Ensure that the card reader cable is not running alongside very high current draw loads.