Test vehicle for selectively inserting diagnostic signals into a bus-connected data-processing system

摘要

A test vehicle capable of being interleaved in a bus-connected data-processing system includes two unidirectional transmission units having outputs connected to opposite ones of bus connecting terminals and inputs connected to such terminals. A direction controller in the vehicle controls the transmission of signals through the unidirectional transmission units. Each of the transmission units has means for receiving diagnostic signals from an external source which also controls the directional controller which in turn controls the transmission units. The direction controller further receives signals from the transmission units for controlling transmission of signals therethrough.