The presence or {HEAD ~ absence} of {TAIL ~ power voltage VDD supply} from the terminal 12 side is determined from the output of detector 33 
of
The presence or { HEAD ~ absence } of { TAIL ~ power voltage VDD supply } from the terminal 12 side is determined from the output of detector 33
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH