The concept of interoperability is based upon standardization of combat vehicles at the subsystem level. Past attempts at international system level development have been frustrated by such factors as a diversity of design philosophy, deployment schedules, production unit cost, and an economic need to maintain commonality with existing national fleets. The logistics potential of common equipment has resulted in renewed interest concerning the use of standardized components. In addition, the heretofore unaddressed area of common crew/equipment interfaces is being investigated. Through careful attention to human factors, a measure of system level standardization may be attained.