Computer connecting line is the external device is connected to the host computer display is divided into cable, cable, power line and data line. Power line is mainly to provide equipment and electricity to charge the battery. The display connecting line is used for connecting the host display card output port or the main board display output port and the input port of the display. Data line mainly through the computer serial port and parallel port and a USB interface and an external input, output or storage devices connected to mutually transmit information, such as the printer to the computer connected to a printer USB cable, phone and computer connections need to be mobile phone USB cable and so on.