The first TAP controller enters an idle state and its control signal is gated to hold the first TAP controller in the idle state until {HEAD ~ the second TAP controller} enters {TAIL ~ the idle state} 
enters
The first TAP controller enters an idle state and its control signal is gated to hold the first TAP controller in the idle state until { HEAD ~ the second TAP controller } enters { TAIL ~ the idle state }
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 HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL