To provide a mask circuit in a control device which controls each signal, enables {HEAD ~ the timing system} to exactly perceive {TAIL ~ a swimmers} touch 
to exactly perceive
To provide a mask circuit in a control device which controls each signal , enables { HEAD ~ the timing system } to exactly perceive { TAIL ~ a swimmers } touch
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH