The impact of commercial off-the-shelf (COTS) equipment on system test and diagnosis

Improved interface standards and reduced design budgets dictate that commercial off-the-shelf (COTS) equipment be more readily integrated into system design. Often COTS is chosen for its functional capabilities and electronic compatibilities with little regard to testability and maintainability features. COTS equipment is often characterized by a lack of detailed information about the specific internal design of the equipment. Complex interactions across an array of subsystems may decrease the diagnosability of the system as a whole where deficits in information occur. In this paper, we describe an analysis approach for assessing system testability and providing system diagnostics that is amenable to including COTS equipment in the system under test. We illustrate the approach with the standard analysis of a system consisting of several subsystems with full information available