Hi, I have just bought a standard horizon gx1500e VHF. This has an NMEA input and a NMEA output allowing the position of a distress call to be shown on the plotter. But I am getting a bit stumped on the wiring.
The S/H diagram shows 3 wires between radio and plotter, with the green, I presume, acting as a common return for both NMEA paths from the radio.
Originally I tried the radio blue (input+) to the plotter blue (out+) and the radio gray (output+) to the plotter brown (in-). That did not work. So I swapped the radio gray for the green. This worked in as much as the dsc function now works, the plotter is talking to the radio. But I am unsure of the connections for the radio to talk to the plotter.
The plotter has inputs for two NMEA devices and I suspect that I will have to use "NMEA device 2" as well, but that needs 4 wires and I only have 3.
There are two possibilities here, use the radio brown wire (nmea output -, no connection), or connect together the plotter violet and brown and connect them to the radio green wire.
I could try these combinations out but I am not sure if it is possible to damage the units by making a wrong connection.
The third picture is essentially the same as the second but with a bit more information.
I have never dabbled with this before, so any ideas?