That USB "Universal Serial Bus", the Chinese name for Universal Serial Bus. This is a new interface technology in recent years gradually widely in the field of PC applications. USB interface has faster transmission speed, hot-swappable and features of connecting multiple devices. It has been widely adopted in various types of external devices. Currently, there are three USB Interface: USB1.1 and USB2.0, and usb3.0 emerged in recent years. Theoretically USB1.1 transfer speeds of up to 12Mbps / sec, USB2.0 can reach speeds of 480Mbps / sec, and can be backward compatible with USB1.1.
　　With the rapid development of computer hardware, peripherals increased, keyboards, mice, modems, printers, scanners have long been known, digital cameras, MP3 players followed, so much equipment, how to access the personal computer? USB is for this purpose created.