Int 14 Fn FF01  - Ibm/yale Ebios Serial I/o - Set Send Buffer              [S]

   AX = FF01h
   CX = length of buffer (0000h to cancel buffer assignment)
   DX = port (00h-03h)
   ES:BX -> send buffer

Return: nothing

See Also: AH=18h,AH=83h"COURIERS",AH=A5h"BAPI",AH=FCh,AX=FF02h