One of the reasons I hate Microsoft is because they removed the very helpful and free hypertext program from Windows after XP. It allowed you to
monitor NMEA data on a
laptop.
Unfortunately, the process is kind of geeky. You will need to disconnect the two
NMEA input wires from the 802, connect them to pins 2 (+) & 5(-) of a nine pin
serial cord, connect the
serial plug into a serial/usb converter, load the drivers for the converter, find the right com port, then set the monitoring program (hpertext,
Opencpn, gpsdiag,etc to the right baud rate (4800) and com port, and look at the data. If you see data, then
work on the 802 settings. If you don't see data, check the settings for source GPS output.
If you feel like getting more geeky, hook a
scope across the two wires and you will see little square waves dance across the
screen if there is data flowing.