Copy and paste from a friend from another site.
Hi Brettoh, I have a NSS9 Evo2 networked to a HDS7 gen 1. using NMEA2000 and Ethernet. A single transducer and the GPS in the NSS are the prime data sources. I get FULL functionality... almost. If I had a gen 2 or better HDS I could network the map card as well, as it is I have a card in each unit.
Initiate a new waypoint, eg MOB, and it immediately appears on the other unit.
Old HDS are relatively inexpensive.
Good luck.