Capture (INT 21h, DFh - Novell NetWare 4.0)

        Entry:
          AH = DFh
          AL = subfunction
                 00h  Start LPT capture
                 01h  End LPT capture
                 02h  Cancel LPT capture
                 03h  Flush LPT capture
                 04h  Start specific capture
                 05h  End specific capture
                 06h  Cancel specific capture
                 07h  Flush specific capture
        Return:
          AL = error code