USB OTG - technical definition

(USB On The Go) An enhancement to USB that enables portable USB devices to be cabled directly together without the need for a PC in between. Fully compliant with USB 2.0, USB OTG devices began to ship in 2002. These "dual-role" devices can also connect to a PC, but when cabled to each other, an automatic negotiation makes one the host and the other the peripheral. See USB.