This is probably a basic answer but it could apply. As you know, most buddy box operation with a computer radio as the master, and a computer radio as the slave, they both must be set up exactly the same. I don't know about your setup because I am unfamiliar with the JR radio you discuss in your OP.

To be honest with you, I have not yet set up my DX7 for use as a master on a buddy box situation. All I know is that when two computer radios are in use, they must be set up exactly the same. If this means they will not work at all or will work strangely, I don't know. I ran into this with my Airtronics way back when, and ended up using the computer radio as master and a regular, non-powered buddy box as the slave, and there were no computer controls available with the buddy box setup this way.

If you find out, (other than as a reply) please forward the info. It would be good to know the setup to make it work.

CGr.