How do I access the serial (RS232) port in Python?

To access the serial port in Python, use the pyserial module, which Python Serial Port Extension for Win32, OSX, Linux, BSD, Jython, IronPython.

Let us see the features -

• Access to the port settings through Python properties.
• Support for different byte sizes, stop bits, parity and flow control with RTS/CTS and/or Xon/Xoff.
• Working with or without receive timeout.
• The files in this package are 100% pure Python.
• The port is set up for binary transmission. No NULL byte stripping, CR-LF translation etc.

To install pyserial, use pip

pip install pyserial

At first import the required libraries.

import time
import serial

Then, configure the serial connections.

ser = serial.Serial(
   port='Enter Port',
   baudrate=9600,
   parity=serial.PARITY_ODD,
   stopbits=serial.STOPBITS_TWO,
   bytesize=serial.SEVENBITS
)

Get keyboard input using the input()

input = 1
while 1:
   # get keyboard input
   input = input(">> ")
   if input == 'exit':
      ser.close()
      exit()

If input is not equal to exit, send the character to the device using the write()

else:
   ser.write(input + '\r\n')
   out = ''

Wait one second before reading output.

time.sleep(1)
while ser.inWaiting() > 0:
   out += ser.read(1)

if out != '':
   print
   ">>" + out