Int 14 Fn 22  - Hunter 16 - Extended Status                                [S]

   AH = 22h
   DX = port (00h COM1, 01h COM2)

Return: AH = extended status
   BX = number of characters in input buffer
   CX = number of characters in output buffer
Desc:  returns the most recent Extended Status code for the port

See Also: AH=21h"HUNTER"