When trying to connect Furuno Radio Ocean RO4800 VHF radio NMEA0183 AIS output, I found an issue. Other people may experience the same issues so I decided to document the issue and the solution here. BTW: the same VHF radio model is also sold under brand name Furuno.
I wrote it all in the title so that Googlebot would index it. I had an issue that I could not get AIS data to my NMEA network from the Radio Ocean VHF radio. I could see the AIS targets on the radio’s tiny screen, but could not get the data to show up in NMEA network. I Googled extensively and then found someone saying on some discussion forum that he had the same issue and he reversed the polarity of the NMEA0183 out wires and it fixed the issue. He actually thought he had done a mistake wiring them in the first place, but I do not think so, because I fixed the same issue also by reversing the polarity and I am 100% sure that the wires are now connected in a wrong way if you compare to the RO manual. A screenshot from the RO4800 manual is below.
In my case, I needed to connect the NMEA OUT (+) (blue wire) to NMEA IN – and NMEA OUT (-) (grey wire) to NMEA IN + in the receiving unit. I will repeat this in a very large text to make sure Googlebot sees it:
If you have issues with the NMEA (AIS) output on Furuno Radio Ocean RO4800 VHF radio, try reversing the polarity of the NMEA OUT wires (blue and green) by connecting the OUT + to IN – and OUT – to IN +
This will not break anything, but may fix the issue. I say may, because this issue can be limited to certain units.
NMEA IN (GPS position to VHF) on Furuno Radio Ocean RO4800 works exactly as documented in the manual.