Connecting RFD900 Telemetry Radio to Navio2

Can someone help me with the pin outs on this I can’t figure out what the IO17 and IO18 pins are for

Those are Rpi GPIO pins made available through the UART connector. Just use a 4pin/wire cable to connect your RFD900 radio and leave the GPIO pins free.

I can’t get my Navio2 to communicate with my radio baud rate matched and my ground station is picking up the one radio. I have tried switching the radios to make sure they both work and they do I just can’t figure out why mission controller won’t find the telemetry radio on the navio2.

Try to connect both radios to the computer, open them in two terminal windows (like RealTerm, TeraTerm) and check if what you type in one terminal is appearing in the other and vice versa.

I only have one UART usb adapter how can I connect the other to the computer at the same time without a second adapter?

You can connect one of them to Navio and run a serial terminal like “screen” or “minicom” instead.