ORIGINAL: nedyob
Well matbe Hitec will come out with a 2.4 Ghz reciever that will work with both Futaba, JR, Aritronics and maybe even Spectrum. We will see when the dust settles.
NEDYOB
Airtronics just released their own 2.4 system; it's similar in how it transmits to the Futaba system (frequency hopping) but I don't know whether or not they are interchangeable.
However, Futaba and Spektrum/JR are NOT interchangeable, as they use two separate methods of transmitting the signal to the Rx. Futaba rapidly changes frequencies continuously (skipping any that are in use at the time), where Spektrum and JR lock on to two separate frequencies and transmit on both at the same time (it scans when you 1st turn on and finds two that aren't in use)
If you have a Futaba Tx that has a removable module (9C being one of them) you can get a 2.4 module from Spektrum that will fit, and it works under their system, or you can get the Futaba FAAST module and it will work on that system. Rx has to match the particular transmission method.
I bought the Spektrum 2.4 after being a "dyed-in-the-wool" Futaba guy,(Futaba hadn't released theirs at the time, I wanted a new system for the plane I was building) and I like it as far as not having to worry about frequency control. I also have a Futaba 9C that I am going to convert to 2.4 by adding a 2.4 module, but I am going to get the FAAST module, as there are some issues with the Spektrum that I don't like, mainly that the DX-7 Tx doesn't have some of the programmability that my 9C has, and there are some issues I have read about regarding voltage cutoff, that I haven't heard happening with the FAAST system.(and I lost a 1/4 scale Decathlon because of it)
Although Spektrum hasn't said anything (that I know of), they are now shipping their systems with a 6V battery instead of the 4.8V. Maybe that will take care of things.