The fail safe circuit also includes {HEAD ~ circuitry} for preventing {TAIL ~ inadvertent communication} of the signal from the input terminal through the series switching network to the output terminal when one of the switching circuits is in a short circuited state or condition 
for preventing
The fail safe circuit also includes { HEAD ~ circuitry } for preventing { TAIL ~ inadvertent communication } of the signal from the input terminal through the series switching network to the output terminal when one of the switching circuits is in a short circuited state or condition
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH