With the application of the USB technology, the USB specification version 2 has been released in 2000, the USB support has been raised to 480Mbps. USB is constantly occupying the market of PC peripherals, which has become the mainstream of the PC peripheral interface. USB has become a trend in their products. If you want the product to be accepted by the market, developers often have to use USB. Now USB not only become the standard port on the computer motherboard, but also became all computer peripherals (including keyboard, mouse, monitor, printer, digital camera, scanner and game controller, etc.) and the host of a standard protocol. This kind of connection than normal parallel port (parallel port) and serial port (serial port) connecting the main advantages are high speed, low power and support plug and play (Plug& play) and and convenient use and maintenance. So I think USB will become more and more widely used. Especially in the field of electrical engineering, industrial field control, portable test equipment and so on.