USB OTG is the USB On-The-Go the acronym is the technology developed in recent years, December 18, 2001 published by the USB Implementers Forum, mainly used in a variety of devices or connection between mobile devices, for data exchange. In particular, PDA, mobile phones, consumer devices. Changes such as digital cameras, camcorders, printers and other equipment between the different standard connectors, up to 7 kinds of memory card formats for data exchange between inconvenience. USB technology, making the PC and peripherals through a simple way, manufacturing costs will be moderate with a variety of devices, applications we mentioned above, are available through USB bus, as a PC peripheral, under the control of the PC data exchange. However, this convenient exchange, once removed from the PC, the devices can not use USB port to operate, because there is no PC as a device to act as the Host. On-The-Go, the technology is realized in the absence of OTG Host circumstances, to achieve data transfer between devices. Such as digital cameras directly connected to the printer, through OTG technology, connect the two devices see the USB port, will immediately print out photo shoot; also the data in a digital camera through the USB OTG interface sent to the mobile hard disk , field operation there is no need to carry expensive memory card, or carry a portable computer.