Abstract: A programmable hardware adapter for switching between two or more levels of arbitration priority for devices connected to a communications bus without host processor intervention. The adapter is programmed with an external arbitration value at initial program load. A control bit selects whether the arbitration level within the adapter is used for arbitration or if the device's internal arbitration level is used. When the external arbitration level is used to vie for the bus, the adapter's state machine sends a signal to the device to tell it it won or lost, depending on the outcome of the arbitration.