VHF/AIS/NMEA C80 MFD Open CPN setup

[Eirik]

Hi all,
I am planning the following setup in my sail boat:
MFD: Raymarine C80 (in cockpit)
Other: Seatalk network with Tridata, ST6001, SPX10 Autopilot, GPS connected to C80.
Laptop: OpenCPN, version 3.20 (inside)
VHF/AIS: RO4800, Mtech MT550 or Navicom RT650 or similar (inside).
Most of the gear is there, except for the VHF/AIS and the appropraite cables/connectors.
The C80 is currently working nicely with the other Raymarine equipment. I would furthermore like to achieve the following:
- Display AIS targets, etc. on a laptop running OpenCPN
- Display COG, SOG, etc. (as well as other info such as wind, depth, etc.) on laptop running OpenCPN
- Display AIS targets, etc. on C80
- Upload waypoints, routes from OpenCPN to C80
- Possibly display other data (such as wind, depth, etc.) on OpenCPN
- Not always having to run/rely on the PC.


I was wondering if I could hook this up as follows (see illustration):
A. Take NMEA 0183 GPS data (4,8kb) from Raymarine SPX course controller, and feed this to VHF/AIS (these are limited NMEA sentences, but the SPX is supposed to send them out on an NMEA port it has).
B. Take AIS data from VHF/AIS (38,4kb NMEA 0183), and feed this to Open CPN. Here I would need an RS232/RS422 - USB stick
C. Forward AIS data + routes/waypoints, etc. from OpenCPN (again using a USB-RS232/422-USB), and send this as 38,2kb to C80. Again, I would need a RS232 / RS422 - USB converter.
D. Get GPS-data and other NMEA data from C80 into Open CPN
E. When laptop is not running, I would connect B and C (by disconnecting USBs, and using gender DB9 gender changer, and some extra wire to ensure that pins are correct, and that I don’t feed 38,2k NMEA into the VHF/AIS).

Questions:
- Would the setup work as intended? Any caveats?
- I guess that it is possible to configure OpenCPN to forward the AIS data to the C80?
- Do I need RS422-USB sticks, or would RS232-USB suffice?
- Any large risks, as these USBs are not opto-isolated (i.e. the fact that I have two USB sticks hooked up), etc.
- Can I use the same USB-RSXX2 stick for both C and D (or do I need two, i.e one for receiving and one for sending)?
- Would it make more sense to mix in and forward the GPS sentences from the VHF/AIS to OpenCPN (instead of getting them from C80 - in my opinion no, but...)
- I guess that I on this setup would miss out on DSC messages to the VHF?
- Is there any software that could spit out NMEA sentences (from Open CPN) to the Ethernet port on the laptop as UDP, which I would then forward to a wifi router for broadcast on the boat to other wireless devices?

Thanks for any input you may provide?

[Eirik]

Opps, looks like the illustration didn't follow. Here it is.

Eirik

[chala]

Originally Posted by Eirik

Take NMEA 0183 GPS data (4,8kb) from Raymarine SPX course controller, and feed this to VHF/AIS (these are limited NMEA sentences, but the SPX is supposed to send them out on an NMEA port it has).

You may only get "heading" out of the SPX and possibly "rudder".