Abstract: A system for interfacing a plurality of stations with a shared device by granting access to the device in the order of requests from the stations. The system elements are serially interconnected for bidirectional communication between the stations and the shared device. Each station employs a register to store a value representing the relative access priority of that station for the shared device. Whenever a station seeks access to the shared device its register is reset to zero and a count-up signal is propagated to all other waiting stations to cause them to increment the values in their registers. When the shared device again becomes available for access the values in the registers are transferred within each station to race counters where they are counted up by a clock until one of the terminals reaches a predetermined maximum count and is granted access to the shared device.