config.txt file description
/tmp/log1.txt		# log file for the data coming from the first port
/tmp/log2.txt		# log file for the data coming from the second port
1			# port number of the first port(1~8)
2			# port number of the second port(1~8)
0			# mode (0: RS232_MODE, 1: RS485_2WIRE_MODE, 2: RS422_MODE, 3: RS485_4WIRE_MODE)
9600			# baudrate of the two ports
0			# parity check(0: none, 1: odd, 2: even, 3: space, 4: mark)
8			# data bits(5~8)
1			# stop bit(1~2)
0			# flow control(0: NO_FLOW_CONTROL, 1: HW_FLOW_CONTROL, 2: SW_FLOW_CONTROL)

