The foreign name of jh-com RS232 RS485 VGA line is video graphics array with 15 pins, which is a D-type interface. The information processed by the graphics card is ultimately output to the display. The output interface of the graphics card is the bridge between the computer and the display, which is responsible for outputting corresponding image signals to the display. CRT display can only accept analog signal input because of design and manufacturing reasons, which requires that the graphics card can input analog signal. VGA interface is the interface for outputting analog signal on the video card. VGA (Video Graphics Array) interface is also called D-sub interface. Although LCD can receive digital signals directly, many low-end products use VGA interface to match VGA interface graphics card. VGA interface is a D-type interface. There are 15 pin holes on it, which are divided into three rows, five in each row