Tests a serial port and cabling using
  a) one serial port transmitting data
  b) another serial port receiving and displaying the data

Usage - Transmitter
  node serialport_test --port /dev/serial --baud 9600 --transmitter

Usage - Receiver 
  node serialport_test --port /dev/serial --baud 9600 --receiver


Other command line arguments

  -h             help
  -l             get list of serial ports on the computer
  --port         set serial port
  --baud         set baud rate
  --parity       set parity to none, even or odd
  --transmitter  program acts as transmitter
  --receiver     program acts as receiver