You have to specify that it's for a JR Radio when you order it. They make them for Hitec & Futaba (negative shift), or JR and Airtronics (I think), which are positive shift. You'll also have to tell them which channel (or frequency).
FM can be transmitted in either PPM or PCM. PPM is the more popular. PCM is quite a bit more expensive when purchasing a receiver.
Dennis-