One of the nice things about NetHomeServer is that it is relatively easy to build your own low cost hardware to control radio and IR devices for home automation via the speaker output of the computer. You can also receive messages via the microphone input. NetHomeServer has encoders which can encode and decode a lot of protocols over the audio channel.
To my surprise I get questions from people that have designed such interfaces. I didn't think there were so many hardware designers out there! I have now collected a few such designs that I have made and some that users has sent to me on a new hardware page. So if you are one of those who have built a nice interface to NetHomeServer (or ProtocolAnalyzer), mail me some pictures and I will publish them too on the HW pages.