A new bus permits processing elements (PE's) to communicate with other PE's entirely under the control of each PE without a separate bus controller. Each PE has means for broadcasting its priority code on a contention portion of the bus and for sampling the bus after a delay in which it has received the codes from other PE's. Each PE holds its priority code on the bus for a further delay during which other PE's can sample the priority code. The PE's resolve contention for access to the information portion of the bus in a multi stage contention sequence. System usage, made possible by peer-to-peer distribution of bus access control, includes dynamic driven priority schemes, a variety of operating modes and hence flexible multiplexing of message traffic.