Original: However , an extension to USB standard specification called USB On-The-Go ( the capitalization oddity is deliberate ) allows a single port to act as either a host or a device -- chosen by which end of the cable plugs into the receptacle on the unit .
Simplified: However , an extension to USB called USB On-The-Go allows a single port to act as either a host or a device -- chosen by which end of the cable plugs into the socket on the unit .