The two low resistance n transistors at the same time connect {HEAD ~ the data lines} to {TAIL ~ ground} 
The two low resistance n transistors at the same time connect { HEAD ~ the data lines } to { TAIL ~ ground }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL