From the reproduced manual page (#5), it appears that the OP's
AIS output is RS-422 (4-wire).
To connect RS-422 to a
laptop, you need a 422-to-USB converter.
I have used p/n XS890 from U.S. Converters (
Serial Data Communication by U.S. Converters LLC) (about $40) with no issues. Converter has four screw terminals on the 422 end (we only use two) and USB cable on the other end.
Once the converter and driver have been installed, you have to use
Hardware Manager to verify that Windows sees it, and then use "Connections" in
OpenCPN to define the same port.
What I have observed is that there is no apparent convention between "A" and "B" and "+" and "-". So try it both ways and see which works.
Disclaimer: all of the installs I've done involved either XP SP3 or Win 7, on the computer end; I've never tried it with Win 8 or 10. I don't
recall the various AISs on the
AIS end, except for
ICOM (which sends both AIS and GPS, so don't need second input for GPS).