Jonte.
Luis is away sailing, but the picture of the AIS looks very similar to the AIT 250 that I have. Since I recently did some adjustments to my own AIS wiring, I may perhaps be able to help.
I think your problem is that your Cobra VHF does not have inbuilt GPS, and so you wish to send the (Plotter)GPS to the VHF? (so the VHF DSC can send GPS location). But you
also wish the AIS to be 'seen' by the Plotter
and by OpenCpn (I presume via WiFi).
First, please note that all NMEA4 inputs are opto isolated, so for example to send data into port 1, you need to correctly connect the inputs to the the PAIR of contacts A1/B1. (see
https://www.vela-navega.com/index.php/nmea-0183-ports).
Please note: I do not understand your comment "
bridge from GND to A2" I hope this may be a mistyping?
To get GPS data to the VHF:
- Your GPS data source is the Garmin Plotter GPS data output NMEA0183 (ut) (brown?) (object 2). (I assume this is 4800 baud?).
- Your Cobra VHF needs 4800 baud GPS. (Yellow and Green).
- You say connecting Yellow to A1 and Green to B1 gives you GPS data on NMEA4 port 1 (at 4800? )
- You now need to send the GPS data to the VHF:
- You can do this two ways:
- You can use the NMEA4 P5 output to copy P1 data to P5 and connect P5 to the VHF. This will allow baud rate conversions, but IMHO this wastes the NMEA4 output!
- A simpler way, if both baud rates are the same, is to connect directly. Most NMEA0183 outputs can drive two or more inputs. So you have the option to possibly simply connect this directly: If you connect Plotter (brown) to Cobra yellow and Cobra Green to ground, You should get the Plotter's GPS showing on the VHF directly.
To see AIS on both the plotter and Open CPN, you need to send the AIS to
both 'receivers'.
NOTE: I am not aware of any Plotters that multiplex data inputs to their outputs. So I do not believe that the Plotter will send out any (received) AIS on its output.
- You have said the plotter sees the AIS when you connect AIS orange Tx cable to the plotters blue Rx cable. This is good!
- You now need to send AIS to OpenCpn!. So the NMEA4 Multiplexer must ALSO be sent the AIS data.
- I would suggest AIS Orange to A2 , with Ground to B2 (baud rate 34800). This should (I hope) give you AIS data on port 2, so you can send it to UDP/TCP etc.
You say "
Also what i belive important is that when the plotter give multiplexer the signal the DSC Distress wont work without the plotter." . Yes, this is correct. Because the GPS data comes from the Plotter you MUST have the Plotter connected for the VHF DSC to operate. It is possible to get the AIS to send GPS data - but this is more complex, and requires programming the AIS, and has other complications.
I do not think this setup actually needs the NMEA4 'output' if the GPS and VHF baud rates are both 4800. But please let me know if I have misunderstood the problem!
Cheers
Dagnall
