Power switching means coupled to {HEAD ~ the interface monitoring} means couples the electronic circuitry to the battery in response to the interface monitoring means determining that {TAIL ~ the interface} is inactive and couples the electronic circuitry to the power receiving means in response to the interface monitoring means determining that the interface is active 
Power switching means coupled to { HEAD ~ the interface monitoring } means couples the electronic circuitry to the battery in response to the interface monitoring means determining that { TAIL ~ the interface } is inactive and couples the electronic circuitry to the power receiving means in response to the interface monitoring means determining that the interface is active
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH