BIOS / Int / Int 68 / 04

                               INT 68 - APPC/PC

Input		Output
AX	04h		AX
BX			BX
CX			CX
			DX
DS:DX	Control Block		CF

Control Block:

                       12 BYTEs reserved
                          WORD  verb (action)
                               2500h TP_ENDED
                               2900h TP_VALID
                        6 BYTEs 0
                          DWORD (high  byte  first)  return  code   (see
                                AH=01h)
                          WORD  0
                        8 BYTEs (high byte first) TP_ID
                          DWORD -> CREATE_TP record  (only  if   verb  =
                                             2900h)