FrSky RC Receiver Connection

I’m so close to getting things working. My NAVIO2 is connecting to my GCS (QGroundControl) and I’ve upgraded all the software in the my FrSky transmitter and receiver, registered and bound them. However, I’m fairly sure I don’t have the RC receiver connected correctly to the NAVIO2. I have a FrSky RX4R and I have connected the first three signals labeled: “-, +, S” to the first connector on the NAVIO2. (see

The NAVIO2 “sees” 16 channels, but no input I do on the transmitter shows up in on my QGroundControl.

I’ve sort have dismissed a registration or binding issue as I fought with that for days until I learned how to upgrade everything FrSky to the current version and now the lights on the receiver and display on the transmitter is showing everything nominal (i.e. registered and bound). I have also set the option for the receiver to “F.Port”.

Anyway, this receiver has a SBUS_out and an SBUS_in (see link) and I think I need to connect that some how, but nothing I’ve tried seemed to work. My default setup guess has them connected to nothing. (only those first three wires “-,+,S”)

Any help from anyone would be GREATLY appreciated as I’m currently out of ideas of what to try.

BTW, I wish someone would update the NAVIO2 docs with regard to RC hardware connections for RC receivers that are still available for sale. (the ones in the docs seem to be all discontinued.)

Thanks in advance!


The Navio docs mention SBUS or PPM RC input is supported. Your receiver has a SBUS output. Why dont you just connect SBUS out to RC in (and ground, V+)?

OK that totally worked. I just hooked up -,+ and the sbus_out on the top pin and it worked perfect.


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