TTS (INT 21h, C7h - Novell NetWare 4.0)

        Entry:
          AH = C7h
          AL = subfunction
                 00h  Begin transaction (NetWare SFT level II)
                      Return: AL = error code
                 01h  End transaction (NetWare SFT level II)
                      Return: AL = error code
                         CX:DX = transaction reference number
                 02h  TTS available (NetWare SFT level II)
                      Return: AL = completion code
                             00h TTS not available
                             01h TTS available
                             FDh TTS available but disabled
                 03h  Abort transaction (NetWare SFT level II)
                      Return: AL = error code
                 04h  Transaction status
                 05h  Get application thresholds
                 06h  Set application thresholds
                 07h  Get workstation thresholds
                 08h  Set workstation thresholds