Page 33 of the manual is pretty clear:</p>

"The T6EX-2.4GHz transmitter may be connected to another T6EX-2.4GHz, or any T4EX, T6EXA, T7C, T9C, T12Z, T14MZ, FX-40 series transmitter."</p>

The 6EX 2.4Ghz transmitter won't work with a plain buddy box, it in fact does need another Futaba computer radio of the same generation that apparently isn't a 12FGA.</p>

Based on this information, your local hobby store should take the buddy box back.  Good luck and good shopping.</p>

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