Marco,
by "local PC", do you mean the PC where the front end runs or where the runtime runs ?
Anyway, in both case there is nothing out of the box available. You will need to use 3rd party components (or write your own).
On the runtime side, you may either write your own C extension or have a look at the Java API if there is nothing that could fit your needs.
On the front-end side:
- if you're running GDC, you can write your C++ DLL Extension - you can for instance use
http://gitorious.org/inbiza-labs/qserialport to do it in Qt to speak the same language as GDC. This would be the cleanest solution. You could use a separate executable, redirect output to a file and get the file via file transfer, but this would not be my preferred way.
- if you're running GWC, I'm afraid the browser limitations are too high for that (except if you're running IE and use GFXAC, so you can use the same DLL as the GDC one, but the scope is very limited).
Hope this helps,
Regards,
Pierre-Nicolas