Here is a diagram of the radio settings of a Turnigy 9XR for use with APM/Pixhawk. Could also be used with any radio with ER9X or OpenTX firmware such as the FlySky Taranis or Turnigy 9X or Flysky TH9X.
I’m using a APM 2.5 with Arducopter firmware on a quadcopter. If you or using a gimbal the remaining radio channels can be used for that. Ch5 is for the 6 position switch in ArduCopter. If using ArduPLANE, that switch moves to channel 8!
In mission planner set my 6 position switch to: Stabilize, Auto, Althold, loiter, land, RTL.
Important! For the 6 position switch (ch5 ‘copter or ch8 ‘plane) your values may vary slightly. My numbers might get you close but you should double check in Mission Planner. Every radio performs slightly different even if its the same model.
Also featured is a wiring diagram for PPM. PPM is great for reducing the amount of wiring. Rangelink, EzUHF, OpenLRS are all good PPM capable 433mhz 1W systems. If you are unsure if your receiver is PPM capable then use the DSM2 selection on menu 1 of the 9XR and add a wire from each channel of the receiver (1,2,3,4,5 and so on) to the APM inputs.
Good luck, I hope this helps someone. Took me many hours to get it correct.