The system 1, wherein said detecting means includes level detector means coupled to said connection terminal means for detecting {HEAD ~ a power supply} from {TAIL ~ said external device} 
from
The system 1 , wherein said detecting means includes level detector means coupled to said connection terminal means for detecting { HEAD ~ a power supply } from { TAIL ~ said external device }
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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL