INT 68 - APPC/PC - TRANSFER MESSAGE DATA
        AH = 05h
        DS:DX -> control block (see below)
Return: control block updated

Format of control block:
Offset  Size    Description
 00h 12 BYTEs   reserved
 0Ch    WORD    1C00h (verb "Transfer Message Data")
 0Eh    BYTE    00h user defined
                01h NMVT
                02h alert subvectors
                03h PDSTATS subvectors
 0Fh  5 BYTEs   00h
 14h    DWORD   (big-endian) return code (see AH=01h/SF=1B00h)
 18h 12 BYTEs   00h
 24h    BYTE    if bit 0 clear, add correlation subvector
                if bit 1 clear, add product set ID subvector
                if bit 2 clear, do SYSLOG
                if bit 3 clear, send SSCP_PU_SESSION
 25h    BYTE    00h
 26h    WORD    length of data
 28h  N BYTEs   data

.