'@param devfile  : Device file under dev filesystem
@param baudrate : Baud rate for serial transmission
@param bytesize : Serial buffer size
@param timeout  : Read/Write timeout'

def __init__(self, devfile='/dev/ttyS0', baudrate=9600, bytesize=8, timeout=1):

    self.devfile = devfile
    self.baudrate = baudrate
    self.bytesize = bytesize
    self.timeout = timeout
    self.open()
