The distributed knockout switch has multiple paths between any input a
nd output pair and thus is inherently robust to faults without the nee
d of adding any additional switch elements. However, to achieve fault
tolerance, one has to first detect and locate the faults. The authors
present an efficient fault diagnosis procedure to detect, locate. and
identify the fault type of single switch element faults for the switch
element array of the distributed knockout switch. To facilitate fault
diagnosis, the operation of switch elements is slightly modified. The
diagnosis procedure can locate most single switch element faults in t
wo phases. Faults which cannot be located in two phases can always be
located in a third phase. Binary search algorithms are developed to lo
cate some kinds of single switch element faults in the third phase.