INT 68 - APPC/PC - CONNECTION CONTROL - POST ON RECEIPT
        AH = 02h subfn 0900h
        DS:DX -> control block
Return: control block updated
SeeAlso: AH=02h/SF=0A00h

Format of control block:
Offset  Size    Description
 00h 12 BYTEs   reserved
 0Ch    WORD    0900h (verb "Post_on_Receipt")
 0Eh    BYTE    1 if MC_ (mapped conversation) form of verb
                0 if basic verb
 0Fh  5 BYTEs   reserved (0)
 14h    WORD    (big-endian) primary return code (see AH=02h/SF=0100h)
 16h    DWORD   (big-endian) error code (see AH=02h/SF=0100h)
 1Ah  8 BYTEs   (big-endian) TP_ID
 22h    DWORD   (big-endian) conversation ID
 26h    WORD    maximum length
 28h    BYTE    fill (0=buffer, 1=LL)

.