import serial
global port
port = serial.Serial(8,19200,serial.EIGHTBITS,serial.PARITY_NONE,serial.STOPBITS_ONE,timeout=5)
port.close()

def HelloWorld():
        message = "Hello World!"
        ClearScreen()
        port.open()
        port.write(message)
        port.close()

def ReadKeys(number):
        key = ''
        ClearScreen()
        port.open()
        port.flushInput()
        for i in range(0,number):
                key += port.read(1)
                port.write(key[i])
        port.close()

def ClearScreen():
        clearscreen = [chr(254), chr(88)]
        port.open()
        for i in clearscreen:
                port.write(i)
        port.close()