Chuck has it right. radios must be compatable. not the same brand just compatable. with the right buddy cord. theres jr to futaba. there's round to round square to square and square to round within futaba and it makes a difference when the 2 radios were built. best thing get together look at the 2 xmitrs and go from there. REMEMBER ONLY TURN ON THE TRANSMITTER THAT THE STUDENT BRINGS DONT TURN ON THE BUDDY BOX.
have fun