{HEAD ~ a pull up unit} which pulls up {TAIL ~ an output terminal} of the data transfer unit in response to an output signal from the first logic unit 
pulls up
{ HEAD ~ a pull up unit } which pulls up { TAIL ~ an output terminal } of the data transfer unit in response to an output signal from the first logic unit
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH