Serial Port Connection Issue

Hi all,

I just got my Arduino Uno and tried to connect it to my computer using USB. However, I can't find the correct serial port while connecting it. The ONLY port that appears in the Tools is called '/dev/cu.Bluetooth-Incoming-Port' and this is obviously not the one I need.

I found some posts and they said this can be the problem of wire. But when I connect it to my computer, the LED turns on.

So why this happens? How can I solve this problem?


is it genuine or a clone? Some clones use other USB chips and you will need drivers for those. the IDE doesn't install them.

If that port disappears when you disconnect the Uno, it is the Uno. What does your operating system (Mac?) think about the board? I'm no a Ma user can't advise there (in Linux the commands would be dmesg and lsusb, maybe the same in the Mac?).

Have you fully inserted the cable at both ends? The inner 2 contacts in the connector are a little further in so if you don't insert completely they might not make contact.

There are usully 4 wires in a cable: Vcc, GND, D+ and D-. Some cables don't have the D+ and D- in which case the LED will turn on when you connect the board to the PC but you will not have data; I however doubt that that is the case with cables that are used with the Uno.

There are "power" USB cables, for charging phones, and "data" USB cables. Only the latter will work with Arduino, so try some other cables.

You can carry out the steps below:

Step 1:

Install the board's core via the Arduino IDE:

· Tools > Board > Boards Manager

· Search for "Arduino AVR Boards"

· From the drop-down menu select latest version

· Click "Install/update"

· Wait for installation to finish

· Click "Close" and restart your IDE.

. Plug your board back to the computer and select the board and port via tools.



  1. Use a data USB cable capable of some 480Mbps and do not use a USB hub.
  2. Remove anything wired to the board.

Step 2: ( Use this if step 1 above fails to solve the problem)

Put your board in bootloader mode by double tapping the rest button (one of the onboard LEDs will fade in and out slowly). While it is in this mode, upload an example sketch from the IDE, say BlinkLED into it, if upload is successful, then tap the rest button once afterwards to exit the bootloader mode.

Now upload the same sample code normally to the board without tapping the reset button, if successful, your board can now be programed with your own code normally.
Note: do not use your own code when the board is in bootloader mode.

If you have a clone board, see Arduino Uno R3 Clone CH340 / CH341 USB driver

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