Listing available com ports with Python

Question

I am searching for a simple method to list all available com port on a PC.

I have found this method but it is Windows-specific: Listing serial (COM) ports on Windows?

I am using Python 3 with pySerial on a Windows 7 PC.

I have found in the pySerial API (http://pyserial.sourceforge.net/pyserial_api.html) a function serial.tools.list_ports.comports() that lists com ports (exactly what I want).

import serial.tools.list_ports
print(list(serial.tools.list_ports.comports()))

But it seems that it doesn't work. When my USB to COM gateway is connected to the PC (I see the COM5 in the Device Manager), this COM port isn't included in the list returned by list_ports.comports(). Instead I only get COM4 which seems to be connected to a modem (I don't see it in the COM&LPT section of Device Manager)!

Do you know why it doesn't work? Have you got another solution which is not system specific?

Answer 1

Basically mentioned this in pyserial documentation https://pyserial.readthedocs.io/en/latest/tools.html#module-serial.tools.list_ports

import serial.tools.list_ports
ports = serial.tools.list_ports.comports()

for port, desc, hwid in sorted(ports):
        print("{}: {} [{}]".format(port, desc, hwid))

Result :

COM1: Communications Port (COM1) [ACPI\PNP0501\1]

COM7: MediaTek USB Port (COM7) [USB VID:PID=0E8D:0003 SER=6 LOCATION=1-2.1]

Answer 2

This is the code I use.

Successfully tested on Windows 8.1 x64, Windows 10 x64, Mac OS X 10.9.x / 10.10.x / 10.11.x and Ubuntu 14.04 / 14.10 / 15.04 / 15.10 with both Python 2 and Python 3.

import sys
import glob
import serial


def serial_ports():
    """ Lists serial port names

        :raises EnvironmentError:
            On unsupported or unknown platforms
        :returns:
            A list of the serial ports available on the system
    """
    if sys.platform.startswith('win'):
        ports = ['COM%s' % (i + 1) for i in range(256)]
    elif sys.platform.startswith('linux') or sys.platform.startswith('cygwin'):
        # this excludes your current terminal "/dev/tty"
        ports = glob.glob('/dev/tty[A-Za-z]*')
    elif sys.platform.startswith('darwin'):
        ports = glob.glob('/dev/tty.*')
    else:
        raise EnvironmentError('Unsupported platform')

    result = []
    for port in ports:
        try:
            s = serial.Serial(port)
            s.close()
            result.append(port)
        except (OSError, serial.SerialException):
            pass
    return result


if __name__ == '__main__':
    print(serial_ports())

Answer 3

You can use:

python -c "import serial.tools.list_ports;print serial.tools.list_ports.comports()"

Filter by know port: python -c "import serial.tools.list_ports;print [port for port in serial.tools.list_ports.comports() if port[2] != 'n/a']"

See more info here: https://pyserial.readthedocs.org/en/latest/tools.html#module-serial.tools.list_ports

Answer 4

A possible refinement to Thomas's excellent answer is to have Linux and possibly OSX also try to open ports and return only those which could be opened. This is because Linux, at least, lists a boatload of ports as files in /dev/ which aren't connected to anything. If you're running in a terminal, /dev/tty is the terminal in which you're working and opening and closing it can goof up your command line, so the glob is designed to not do that. Code:

    # ... Windows code unchanged ...

    elif sys.platform.startswith ('linux'):
        temp_list = glob.glob ('/dev/tty[A-Za-z]*')

    result = []
    for a_port in temp_list:

        try:
            s = serial.Serial(a_port)
            s.close()
            result.append(a_port)
        except serial.SerialException:
            pass

    return result

This modification to Thomas's code has been tested on Ubuntu 14.04 only.