DOS device names - technical definition

DOS device names are reserved names for common input and output devices. See DOS redirection, DOS Sort and DOS Dir.

  Reserved name   Device
  AUX             First connected serial port
  PRN             First connected parallel port
  COM1 thru COM4  Serial ports (modem, mouse, etc.)
  LPT1 thru LPT3  Parallel ports (printer)
  CON             Keyboard and screen
  NUL             Dummy (testing purposes)