Tx.py

import serial
import time
SERIALPORT = "/dev/ttyS0"
#SERIALPORT = "/dev/ttyUSB0"
#SERIALPORT = "/dev/ttyAMA0"
BAUDRATE = 115200
ser = serial.Serial(SERIALPORT, BAUDRATE)
ser.bytesize = serial.EIGHTBITS
ser.parity = serial.PARITY_NONE
ser.stopbits = serial.STOPBITS_ONE
ser.timeout = None
ser.xonxoff = False
ser.rtscts = False
ser.dsrdtr = False
ser.writeTimeout = 0
print ("Starting Up Serial Monitor")

try:
  ser.open()
except Exception as e:
  print ("Exception: Opening serial port: " + str(e))
#finally:
# ser.close()
if ser.isOpen():
  while 1:
    ser.flushInput()
    cmd = input("Enter command or 'exit':")
    if cmd == 'exit’:
      ser.write(cmd.encode('UTF-8')+ b"\n")
      ser.close()
      exit()
    else:
      #ser.write(cmd.encode('ascii')+'\r\n’)
      ser.write(cmd.encode('UTF-8')+ b"\n")
    time.sleep(0.5)
else:
  print ("Cannot open serial port.")