One of the simplest ways to put SeaTalk data onto your NMEA network is to use the Brookhouse Multiplexer (MUX). I am designing a network aboard s/v C# and had the following requirements:

1. PUT DSC information onto the NMEA bus and SeaTalk bus from a Standard Horizon Radio
2. Receive GPS information into the Standard Horizon Radio from the NMEA bus
3. Transfer routes and waypoints from software to the Raymarine C-80 over the network
4. Control the Raymarine ST4000+ Autopilot from nav software or the C-80 (Have one or the other be the source of the route talking)
5. Put AIS from an SR161 information onto the network at 38000 and have it available on the C-80 as well as nav software
6. Have a redundant NMEA GPS wired to a NMEA in (already have a Raymarine SeaTalk GPS)
7. Have all SeaTalk data available to nav software when the C-80 is disconnected

After a quick note to Bookhouse with these requirements, they replied indicating all of this would be possible and provided the graphic below -

See http://www.brookhouseonline.com for their complete product line. The model I purchased was the AIS-C with USB and SeaTalk options.