I just directly connect my thin client (with embedded OS) to a remote machine (Windows 7) via RDP. The problem is, once I try to test the audio via Skype, it seems that the audio/microphone of the remote machine was hidden or not detected, but the remote audio was detected too because I could play music or videos. Is there a way to enable the microphone of the remote machine and used as the microphone of my thin client?
On desktop Windows clients, the mic setting is in the "new connection" dialog, under Local Resources / Remote audio [Settings...] / Remote audio recording: Record from this computer.
However, it sounds like you're trying to record audio on the remote computer, which is not an available option for the native clients. It's possible that other clients can support this feature, but it may also be a limitation of RDP, which would make it impossible.