Method and apparatus for fault testing multiple stage networks

An apparatus for testing the crosspoints of a multiple stage end-marked switching network. The network being tested comprises in each stage at least one orthogonal matrix of bistable, solid-state crosspoints. The network has a predetermined plurality of unique paths between each fixed point at the opposite ends of the network. Those paths are clearly defined in at least one intermediate stage of the network such that the paths can be checked for open circuit conditions and short circuit conditions by enabling specific paths or groups of paths in that stage and inhibiting all other paths or groups of paths. The apparatus shown may be controlled by controls which may be incorporated into a stored program controller controlling the switching network or by means of a computer programmed to perform routining of the exchange including the network.