The Information Multiplex (IMUX) bus is a high speed serial data bus used on military airborne and ground transportable communications systems. A contention protocol is used to provide simplified bus management, i.e., no central controller, fast access for bus users, speed expansion up to 20 Mbits/sec, and system configuration flexibility required in these applications. A hardware fabrication and testing program which demonstrates concept feasibility is described. Results of a computer simulation study reveal bus utilizations up to 95% of maximum bit rates, transmission delay times of less than 1 ms, and stable bus operation.