Some event initiates the subroutine for loading data into shift register 10, or conversely, for reading {HEAD ~ data} out of {TAIL ~ the shift register}, such as an impeding power interruption as discussed previously 
out of
Some event initiates the subroutine for loading data into shift register 10 , or conversely , for reading { HEAD ~ data } out of { TAIL ~ the shift register } , such as an impeding power interruption as discussed previously
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH