![COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center](https://support.arduino.cc/hc/article_attachments/360016539239/COM_port_changes_7.png)
COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center
![arduino nano - Why are the pin numbers of the diagrams and of the code different? - Arduino Stack Exchange arduino nano - Why are the pin numbers of the diagrams and of the code different? - Arduino Stack Exchange](https://i.stack.imgur.com/ICuN3.png)
arduino nano - Why are the pin numbers of the diagrams and of the code different? - Arduino Stack Exchange
![COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center](https://support.arduino.cc/hc/article_attachments/360016532000/COM_port_changes_2.png)
COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center
![COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center](https://support.arduino.cc/hc/article_attachments/360016539219/COM_port_changes_5.png)
COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center
![COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center COM port number changes when connecting board on different ports or in bootloader mode – Arduino Help Center](https://support.arduino.cc/hc/article_attachments/360016532060/COM_port_changes_4.png)