(2017-07-04, 02:22 PM)abarrow Wrote: It's what I suspected - you have a single NMEA in/out on your chartplotter. I think the only way to do this without buying a Seatalk / NMEA bridge is to bring both the TX and RX NMEA on your C80 to your Openplotter RPI, then use another RS422 interface to connect to your GPS for incoming position data to Openplotter, which would then feed that position data to you C80. Essentially, your OpenPlotter RPI becomes your multiplexer, which is one of the things it is designed to be. Your RPI/Openplotter will have to be powered up and working at all times, otherwise your C80 will not get GPS.
Yes I agree with abarrow
As he says you will rely on OpenPlotter to multiplex your NMEA data and send the GPS signal on to your C80 but that is what OP does !
Works fine on my boat
Ive attached a schematic for information. In your setup, your C80 will take the place of my Seatalk-NMEA bridge