Finding the right serial port name

To communicate with a device, you first need to open the serial port that it's connected to. Before that, you need to know the name of the serial port to use. Select your operating system to find instructions for determining the serial port name:

1. Open Windows Device Manager.
2. Find "Ports (COM & LPT)" in the list.
3. Expand "Ports (COM & LPT)" to see the names of all serial ports.

The title of your serial port depends on the way you connect the device to the computer:

In any case, the port name is the text in brackets (i.e. COM3 in the previous examples).

If there are multiple ports that look like they may be valid, you may need to try them to see which connection works.

See a video of how to find the port name.

Enter the following command in a terminal:

ls /dev | grep -E 'ttyUSB|ttyACM'
# Example output:
# ttyUSB0
Copy

If you are using USB to connect your devices, the output will likely be ttyUSB0. The port name is the output with the directory included: /dev/ttyUSB0.

Enter the following command in a terminal:

ls /dev/tty.*
# Example output:
# tty.usbserial-A4017DXH
Copy

If you are using USB to connect your devices, the output will look something like tty.usbserial-A4017DXH. The port name is the output with the directory included: /dev/tty.usbserial-A4017DXH.

Example Code

We have a Python COM Port Scan example that shows how to programmatically check all serial ports for Zaber devices.