This resets counter 40 to zero on the possibility that a few counts may have been registered due to interference or spurious signals appearing at {HEAD ~ input} 42 at {TAIL ~ some previous time} 
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This resets counter 40 to zero on the possibility that a few counts may have been registered due to interference or spurious signals appearing at { HEAD ~ input } 42 at { TAIL ~ some previous time }
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 HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL