Hello robjl,
Yes, you can control on what you want to output out of data port 1, 2 and 4 on an RDP149. As long you have good data on your display and the Simrad you're interfacing with is compatible with NMEA0183 version 1.5/2.0. If you’re using data port 2, make sure the baud rate and NMEA version is set the same on the Simrad. You would need a 6 pin nmea cable (part number 000-154-054) the two wires you are going to use to output from the RDP149 on port 2 off the cable is white and black. White is output + and Black is output -.
Connect white to the Simrad receive + and black to their receive -. After making the connection, have the unit turned on, select menu, system configuration, system setup, port setup, data port 2, on the screen you can check the baud rate, nmea version. On the right side of the screen select “Select Sentence” and turn on DPT or DBT (depth) and VTW (water speed) or SOG (speed over ground).
YachtyBoy
