Most but not all Futaba txs will work as a buddy box. Look to see if it has a socket.

Older Txs had a round socket. Newer ones are square.

The slave needs neither battery nor to be switched on.

There is a Futaba support forum here http://www.rcuniverse.com/forum/futa...ort-forum-125/

Once you have the exact model numbers of both Txs you could ask there.