Garmin AIS 300. Connect to 2 Garmin chart plotters?

[Yeoman_24]

I have Garmin AIS 300 ; GPSmap 820 Primary plotter and GPSmap 520 secondary plotter.

ConnectIons are through NMEA 0183 data wires.

AIS is connected to 820 by AIS grey tx A + to GPS violet Port 2 Rx in.

There is a pink tx B - from the AIS unit. Can I connect this to the brown port 1 rx in on my GPSmap 520 to see AIS on my secondary plotter down below?

Pic 1 AIS, pics 2 and 3 GPS 820, pic 4 GPS 520

 

[PaulRainbow]

I have Garmin AIS 300 ; GPSmap 820 Primary plotter and GPSmap 520 secondary plotter.

ConnectIons are through NMEA 0183 data wires.

AIS is connected to 820 by AIS grey tx A + to GPS violet Port 2 Rx in.

There is a pink tx B - from the AIS unit. Can I connect this to the brown port 1 rx in on my GPSmap 520 to see AIS on my secondary plotter down below?

Pic 1 AIS, pics 2 and 3 GPS 820, pic 4 GPS 520

No. The pink AIS wire would be used for displays that don't use the -ve for NMEA. In your case, connect the AIS grey wire to Brown or violet on the 520, in addition to the 820 violet.

 

[Yeoman_24]

No. The pink AIS wire would be used for displays that don't use the -ve for NMEA. In your case, connect the AIS grey wire to Brown or violet on the 520, in addition to the 820 violet.

Thanks for the reply. I do get confused with NMEA as there is so much varying advice on the web that trying to work it out is not easy.
So, one nmea transmitter can feed two receivers?
When do I need to consider the opposing return / transmit wire?
What is the purpose of the shield and where and when should I connect it?
And finally PaulRainbow (and others), if I post a picture of my proposed set up (I'm just finishing a good wiring diagram, well I think it is good, lol) could you let me have your thoughts and advice please?
My setup is slightly further complicated as I also have a Seatalk-ng backbone with Raymarine autopilot ..... (just what I inherited!) which the GPSmap 820 connects to through NMEA 2000 (and I think grounds through Seatalk too as only the +ve connects to the fused 12v switch??? Arrrrrrrrgh! Lookingf forward to some more help please! I can send any manuals you need to help me!
Thanks all.......

 

[PaulRainbow]

Thanks for the reply. I do get confused with NMEA as there is so much varying advice on the web that trying to work it out is not easy.
So, one nmea transmitter can feed two receivers?

Yes, sometimes more.

When do I need to consider the opposing return / transmit wire

If you mean the pink TX B -, you don't, not with your current setup. Most NMEA devices would use the + and - (that's how it's supposed to be, officially) but Garmin use the 12v - for NMEA return, so that connection is redundant. There are cases where the AIS TX B - would need to be connected to 12v -, but as yours is working without, leave it as it is.

What is the purpose of the shield and where and when should I connect it?

Which shield ?

And finally PaulRainbow (and others), if I post a picture of my proposed set up (I'm just finishing a good wiring diagram, well I think it is good, lol) could you let me have your thoughts and advice please?
My setup is slightly further complicated as I also have a Seatalk-ng backbone with Raymarine autopilot ..... (just what I inherited!) which the GPSmap 820 connects to through NMEA 2000 (and I think grounds through Seatalk too as only the +ve connects to the fused 12v switch??? Arrrrrrrrgh! Lookingf forward to some more help please! I can send any manuals you need to help me!
Thanks all.......

Of course, i'd suggest a new thread for that.