I have a 93sv in my console and a 73sv on the bow.
I have them linked with the 0183 wiring. I also have a digital speedometer linked in with the console out NMEA wire (22 awg).

I can share waypoints between the garmins ok, but the speedo does not recognize the NMEA connection.

Question? Do I have to have data sharing turned on for the NMEA to work?
When I do turn it on, it defaults (makes me change to Gramin High Speed), rather than NMEA std, or NMEA high speed. I think this is what may be causing my speedo not to recognize the connection. Its a beede nexsys link (4800 baud it think) and it says "missing NMEA data". This is on a new bass cat.