I have a Futaba TX charge cable with banana plugs on the other end. I use that cable to charge both my Futaba 9C and my DX7, it will fit both. Since the DX7 has reverse polarity, I just swap the red & black banana plugs at the charger. The chargers I have show the battery voltage, and will not allow me to charge if I have reverse polarity, so I don't worry about forgetting to swap them.