RE: JR Radio, non JR (Futaba) Connectors
I have been a Futaba user since I first started in RC, in 1978. I have an 8AUPS and a 9C. A few years ago, I got a deal on an aircraft that came with a JR8103. I have since purchased a JR9303 and added the 2.4 module.
A JR male will fit in a Futaba female. I have modified the Futaba male, as described above. It takes some time to get the modified Futaba male to fit in the JR female, but it works. You need to be careful with polarity as the modified Futaba connector will fit in the JR female either way. You can also cut off the Futaba male and solder on the JR male. I also have purchased MPI universal extentions. They come with a JR male and a Futaba/JR female. Using these adapters, you do not need to modify anything. It obviously adds extra cost to the setup.
JR batteries and JR servos will fit in Futaba receivers and switch harnesses. Futaba batteries and servos will not fit in JR receivers and switch harnesses without an adapter or conversion.