Why? Why would you want to use audio for Lync in an RDP session? Well, many reasons, for me I want to make a test call to watch QoS markings to a tiny office without getting on a flight. That being said, it doesn’t necessarily work out of the box. Here’s a tip that will help you.
First, when you connect, make sure that your local resources in the RDP client allow for both audio playback and audio recording as seen in the following screenshot.
However, you can’t stop here. By default in Windows 7 and 2008 R2 you’ll find that the remote workstation/server will report that there’s no audio recording device available, even if it plays back sound and you can here it. That’s because audio recording redirection is disabled by default, and you’ll need a registry hack (or GPO) to get it going. As seen in this article http://support.microsoft.com/kb/2020918, we need to change the value of HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp\fDisableAudioCapture to 0 (that’s a zero). Almost immediately, you should be able to record audio, however you might need to bounce the Lync client.