Jan 24

The card reader was once working and now it’s not working. No Events are showing for one reader and LED signalling is not changing state?

Find out how to diagnose and fix the issue here:

Measure the card reader’s voltage.
If the voltage (12 VDC-to-signal ground) is below 10 VDC (when cable is connected and not connected), then card reader port is burnt from unknown causes.
If not, check the card reader or card reader cable for damage.