This setup is using Serial, not Wiegand. The third pin (the one next to the two antenna loop pins) is connected to +5V so it is HIGH. The description clearly describes the pin as "3. high-level election serial port, low-level selection of Wigan, not vacant"
If you are connecting to an Arduino with a spare hardware serial port (Leonardo, Micro, MEGA) then use hardware serial. Otherwise use SoftwareSerial.h. Connect Pin 5 (marked TX on the board) to the RX on your Arduino. I don't see any baud rate specification so try everything from 9600 on up until you receive clear data when a card is detected.