First, it is important to observe if the green LED flashes friefly after the card is read or after PIN is entered. This indicates that the reader read the card and successfully transmitted data that the reader believes is valid.
The Weigand format being sent by the reader may not match the format settings in the legacy system. In this case, some access systems will display no data and some access systems will indicate "invalid card format."
It is also important to verify the Weigand wires are properly connected.
Note: This solution is for BridgePoint NX model readers being utilized in PIN-to-Card (not PIN-to-Panel) mode.