Abstract: A system module 20 includes a processor 10, a system bus 15, a local bus 11 coupled to the processor, arbitration circuitry 12 coupled to the local bus and the system bus for providing common hardware protocol for distributed mode and central mode operations, and protocol control circuitry 13 coupled to the arbitration circuitry, the system bus, and the local bus for providing a system bus request to the arbitration circuitry when the system module desires to perform a bus transaction. The local bus 11 may be a processor bus on a system module while the system bus 15 may be an architecture bus standard such as Futurebus+. Also a method of operating arbiter circuitry in distributed mode or central mode where no change in hardware or software is needed when switching system operations between distributed and central modes.