I'm trying to watch serial ports.

For that I need the serial port address, but... on the network people's says that address follow unix pattern, like this "/dev/ttyUSB0", but if I enter on raspbian terminal and type.

ls /dev/ttyUSB*

I recieve this mesage

ls: cannot access /dev/ttyUSB*: No such file or directory

I've already tried PySerial, but when i ran the script, the terminal return me an huge error saying what the serial port doesn't exist.

I need some help, I want get away of this problem faster possible.

  • That comes up for me sometimes so I searched. No clean way, but "dmsg | grep tty' seems to work
    – PaulF8080
    Jan 5, 2017 at 22:25

1 Answer 1


The name given to the serial port depends principally on how but also on what you have connected.

If you connect a 3.3V safe TTL serial link to the Pi's GPIO (pins 8/10) then the serial port is called /dev/ttyAMA0 or (rarely) /dev/ttyS0. On Raspbian you should preferentially use the link /dev/serial0.

If you connect via a USB dongle plugged in to the Pi the serial port will normally be named /dev/ttyUSB0 for the first, /dev/ttyUSB1 for the second etc. An exception is if the other end of the dongle is connected to an Arduino in which case the port is likely to be named /dev/ttyACM0.

  • I did it, I connected an Arduino in one USB port, and the /dev/ttyUSB0 appeared.
    – lambda
    Dec 31, 2016 at 14:14
  • Its so confusing all these port names ...
    – Piotr Kula
    Jan 5, 2017 at 15:05

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