Windows 98 or 2000, Direct X 8.0 or above must be installed. Uses mic port on the sound card. Audio Recording is a very sensitive area, please place proper notices. Windows XP is supplied with Direct X 8.0. ALL BDS series Boards have 1 audio channels. Besure to read "Privacy Guidlines for use of Video Surveillance Technology by Public Bodies" found at the links at the bottom of the pages. or click here http://www.dvrmart.com/privacy_dvr.html