I've got an old Craftsman GDO which I recently got a Liftmaster 65 wired keypad for. The GDO has four terminals: white red black and yellow. The red and white are the primary control of course. Does anyone know what the black and yellow terminals are for? I'm hoping one of them can be used to provide power for the keypad so that I don't have to install a transformer or keep replacing the batteries. Thanks in advance,

David Mitchell