Int 21 Fn 5F98  - LANtastic - Send Unsolicited Message                     [N]

   AX = 5F98h
   DS:SI -> message buffer (see below)

Return: CF clear if successful
   CF set on error
       AX = error code

Note:  v4.1- return no errors

See Also: AX=5F99h

Format of message buffer:
Offset Size    Description
 00h   BYTE    reserved
 01h   BYTE    message type
       00h general
       01h server warning
       02h-7Fh reserved
       80h-FFh user-defined
 02h 16 BYTEs  ASCIZ destination machine name
 12h 16 BYTEs  ASCIZ server name which user must be logged into
 22h 16 BYTEs  ASCIZ user name
 32h 16 BYTEs  ASCIZ originating machine name (filled in when received)
 42h 80 BYTEs  message text