The pump down circuit may be configured to generate a pump down signal in {TAIL ~ response} to {HEAD ~ the pump} up signal and the control signal 
The pump down circuit may be configured to generate a pump down signal in { TAIL ~ response } to { HEAD ~ the pump } up signal and the control signal
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH