INT 21 - Novell NetWare - MESSAGE SERVICES - SEND BROADCAST MESSAGE
        AH = E1h subfn 00h
        DS:SI -> request buffer (see below)
        ES:DI -> reply buffer (see below)
Return: AL = status
            00h successful
            FEh I/O error or out of dynamic workspace
Note:   this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AH=DEh/DL=04h,AH=E1h/SF=01h,AH=E1h/SF=04h

Format of request buffer:
Offset  Size    Description
 00h    WORD    length of following data (max 9Eh)
 02h    BYTE    00h (subfunction "Send Broadcast Message")
 03h    BYTE    number of connections (01h-64h)
 04h  N BYTEs   list of connections to receive broadcast message
        BYTE    length of message (01h-37h)
      N BYTEs   broadcast message (no control characters or characters > 7Eh)

Format of reply buffer:
Offset  Size    Description
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs   list of per-connection results
                00h successful
                FCh message rejected due to lack of buffer space
                FDh invalid connection number
                FFh blocked (see also AH=E1h/SF=02h)