Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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▀ In most MS-DOS systems, the serial device is unbuffered and is not
  interrupt driven. If the auxiliary device sends data faster than your
  program can process it, characters may be lost.
 
▀ At startup on the IBM PC, PC-DOS initializes the first serial port to
  2400 baud, no parity, 1 stop bit, and 8 data bits. Other implementa-
  tions of MS-DOS may initialize the serial device differently.
 
▀ There is no way for a user program to read the status of the auxiliary
  device or to detect I/O errors (such as lost characters) through this
  function call. On the IBM PC, more precise control may be obtained by
  calling ROM BIOS Int 14H or by driving the communications controller
  directly.
 
▀ If a CTRL+C is detected at the keyboard, an Int 23H is executed.
 
▀ You can also input from the auxiliary device by requesting a read (Int
  21H Function 3FH) using the predefined handle for the standard aux-
  iliary device (0003H) or using a handle obtained by opening the logical
  device AUX.
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