Quote Originally Posted by tasmod View Post
Thought I posted that. Radio module is available 3.3v only.

So Pic and radio module are at 3.3v. Voltage reg in photos is 3.3v device.
That doesn't necessarily mean that RX & TX are at 3.3V. The purpose of chips like the MAX232 is to boost the supply voltage to RS232 levels which can be +/-15V.

However, since the ARF is an upgrade of Ciseco's XRF, it probably is wired the same and there is documentation for the latter showing RX & TX directly connected to the microcontroller. It would help if they correctly identified their devices as using a low voltage serial link rather than being RS232 which implies much higher voltage levels.

As Henrik said, the only way to be sure is to try it. The TX level is likely to be ~3V at best. You can check the PIC datasheet to see if that's adequate.