1, connect the computer and the serial port, and then connect the serial port? 2 holes? And then what? 3 holes (serial port marked with numbers, don't make a mistake), use? Wires? Or? A pin? short connection

2. Check the serial number, click Computer, and then right-click Manage.

3. After jumping out of the dialog box, click? Device Manager, expand? Ports (COM and LPT), can you see our serial number? COM9

4. Open the serial debugging assistant. Without serial debugging assistant, you can download it online by yourself. What is the serial number first? COM9

5. Then click: Open serial port? button

6. Enter a string of numbers 1 1 22 33 44 55 in the sending area, and then click: Send 7. In the receiving area, the same content as the sending area will be displayed. Click Send Once and Receive Once, and you can see that the numbers sent and received are the same. Suppose you click send, but you don't receive it, or you receive garbled code, and the normal computer host and serial port can't communicate normally.