{HEAD ~ The power circuit} can be configured to engage a battery power supply or {TAIL ~ an alternating current supply} 
{ HEAD ~ The power circuit } can be configured to engage a battery power supply or { TAIL ~ an alternating current supply }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL