Int 7A Fn 09  - Ibm 3270 Workstation Program Api - 3270 Emulation          [I]

   AH = 09h
   BX = 8020h
   CX = 00FFh
   DX = ID of 3270EML
   AL = service
       01h connect
       02h disconnect
   ES:DI -> control block

Return: ???