Int 21 Fn FF80  - Topware Network Os V5.10+ - Send Message                 [N]

   AX = FF80h
   DH = FFh
   DL = destination address (FFh for broadcast)
   CX = message length (max 2000)
   DS:SI -> message to be sent (see #2218)

Return: nothing
Program: TopWare Network Operating System is manufactured by Grand Computer
     Company

Notes: this function is supported on both Workstations and the server
   there is no guarantee that the message will be received correctly, or
     at all, by the destination

Format of TopWare message:
Offset Size    Description (Table 2218)
 00h   BYTE    type code
       07h TopSend
       11h user application
       other reserved for TopWare
 01h   var data

Note:  sending messages with a type code other than 11h will cause
     unpredictable results