X-Plane can communicate with external entities a couple of ways.

1. Within X-Plane, configuration can be set up to send to a selected IP address selected parameters via UDP
2. From outside of X-Plane, where another entity can send UDP packets which request registration to known X-Plane IP address/port: X-Plane UDP Docs (from Instructions directory “NOTE: X-Plane always receives on port 49000.”

[9/7/2019]

Worked several hours today and yesterday trying to get the RREF part of UDP communications to work between the Raspberry Pi and X-Plane 11.36r2. After looking at the log.txt, it appears that when I send a request for a Dataref to be sent, it starts sending the data on a random port. And I can't determine that port - only available in Log.txt. Sent a Bug report to X-Plane to see if they will take a look. Solution was to change the parameters of the code that sends to X-Plane so that it includes the port.

Right now, I'm coding on the Raspberry Pi via Geany, which is a GUI application. I am using VNC to remotely access the Raspberry Pi. At this point, the code is all “play” - trying to get the communications to work.

Was successful in sending from the Raspberry Pi to run a X-Plane Command (Flaps Up), and it works perfectly.

Wrote a4SimData.json in the Projects A4Simulator directory. Considering letting one file be read by a like X-Plane plugin, as well as by the Raspberry Pi Connector code.