fakeclient.py

import serial

with serial.Serial("COM3", 9600) as ser:
	while True:
		s = ser.read()

		if (s == b'o'):
			print "Restart"
			# Alive
			ser.write(b'n')

		elif (s == b'm'):
			print "Ping"
			# Pong
			ser.write(b'l')

		elif (s == b'y'):
			print "Posizione iniziale"

		elif (s == b'z'):
			print "Inizia percorso"

		else:
			print s