TYPE: Micro USB To OTG
USB On-The-Go An enhancement to the Universal Serial Bus (USB) that enables portable devices to be cabled together via USB without a computer in between.
OTG creates a "dual-role" device that can act as host or peripheral.
When OTG devices are cabled to each other, an automatic negotiation makes one the host and the other the peripheral.
Fully compliant as of USB 2.0, USB OTG devices began to ship in 2002.