That board changes your validator to an RS-232 serial interface. WMS at then end did away with that board and provided their own solution attached to the back of the validator cage. If you have another WBA 11 that is known to be working on another machine, you could just swap them out and install the board and eprom with correct firmware on the other validator to see if it works. If the RS-232 board is bad you are going to have to find another one of those, or get the WMS rs-232 bv interface with necessary harnesses, or you could get an mei validator 6607 with the correct harness and firmware.