NetHomeServer can use the speaker audio output to send protocol signals for IR or Radio (RF) protocols. To actually send them as IR or RF, you need some kind of additional hardware that can transform them. In the same manner, the microphone input can be used to decode such protocols, and again you need some kind of hardware to receive them.

To use

Fortunatly, building these interfaces is not very hard. You can do it by modifying existing devices or by using special built devices. Here are a few examples of devices I and some other users have built.