In {HEAD ~ the case} of {TAIL ~ a negative logic signal}, the signal is active low where the logically true state corresponds to a logic level zero 
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In { HEAD ~ the case } of { TAIL ~ a negative logic signal } , the signal is active low where the logically true state corresponds to a logic level zero
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH