Abstract: A vending control system and method for interfacing a control device to a vending machine having input/output control lines along which are transmitted control signals for controlling the operation of the vending machine. The control device includes, means for connecting to the control lines of the vending machine, means for reading the control signal, means for determining operational responses/outputs of the vending machine which correspond to the control signals, means for storing the control signals and information concerning the operational responses and means for reading the stored information to control the vending machine.