Hi John,
Boy, you are just too smart sometimes <grin>...
Yes, you are right, the host system (either LD or Showtime, or any other program that uses the LD2000.DLL) does send out a broadcast as a means of finding all of the remote systems and all of the remote QM2000 boards. Port 9021 is one of Pangolin's registered (and certified) port numbers.
We do this broadcast method to completely automate the network setup. One of our goals was to make networking easy and transparent. Clients who have used our networking system and competitor's systems tell us that they really hated the drudgery of noting and manually configuring IP numbers and such, and they love our system because it is completely automatic and transparent.
Our networking scheme is quite effective in automating the network setup process, but it does not currently allow for manual configuration. Actually the broadcast that we send out does more than just allow us to find the networked QM2000 boards. It also does some initial configuration as well. Even if we allowed manual IP configuration, we we really could not do without the broadcast.
Contrary to popular belief, broadcast messages can be sent through a router, but you have to configure the router to allow them.
The only down-side to our networking scheme is that it won't work on the internet. BUT!! The amount of trafic that we send won't really work over the internet anyway. We felt that the compromise of not being able to use the LD2000 network over the internet was worth the benefits in terms of ease of use.
Technically speaking, the networking system used in LD2000 is the same one we had been using in our older LD/QM32 system since 1997. So far, we have not had any clients report problems due to the broadcast message. But if a client comes to us with a problem, we will certainly examine it and work toward a solution, just as we always do...
Best regards,
William Benner
Pangolin Laser Systems
