NMEA0183 input on WestMarine VHFDSC500 -- wiring to NMEA +/- Outputs on C80 chart plotter

I am buying an old'ish boat that has a Raymarine C80 chartplotter and a West Marine VHF DSC500 radio. The radio is currently not connected to a GPS source, so if I used DSC I'd need to manually enter coordinates; seems like that would be missing the point. I want to connect the NMEA Out (-ve)/Out(+ve) from the chartplotter to the NMEA input on the radio but I'm a little unclear on the wiring because the signal naming conventions vary between the devices.

The C80's NMEA connector is 5-pin, shown here

The DSC500 is an 8-pin connector but it doesn't have +/- NMEA inputs like newer radios, although the user manual says it's a NMEA0183 compatible interface. It looks like this:

What seems obvious (but possibly wrong haha) is that I would wire C80 YELLOW (Output(+ve)) to DSC500 Pin 4 GRN "GPS Data In".

Wiring the C80 BROWN Output (-ve) to the DSC500 is less obvious. I propose I need to wire it to the External Speaker (-) GND (BLK).

Would this proposed wiring be correct? If not, any insights you can provide would be appreciated.




  • Probably doesn’t matter but the radio model above is slightly wrong, it’s a West Marine VHF500dsc, which was made by Uniden. I’m happy to experiment but was hoping for a connector to mate to the accessory port. Does anyone recognise that style connector?

    I could also just cut the radio connector off, strip the BLK and GRN wires, and connect them to a cable going to the C80’s NMEA port. I’d safely terminate the other wires so they don’t cause problems.

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