I have one audio control interface which defines 5 input terminals. The input terminals are connected to one usb streaming output terminal through mixer unit. Then usb streaming output terminal is mapped to one audio streaming interface which defines one isochronous IN endpoint. Thanks, Lukasz From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts Sent: Monday, September 10, 2012 7:26 PM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: Windows usbaudio.sys architecture question Bartosik Lukasz-ALB045 wrote: Hello, We are developing USB audio device which will use generic usbaudio.sys driver provided by Windows 7. The device's USB descriptors define 5 input mono terminals (2 headsets, 1 microphone, 2 lines in) which use one isochronous IN USB endpoint to transport audio data from the device to Windows OS. Your description is a little bit vague. Do you mean you have one audio control interface, one audio streaming interface, and one isochronous endpoint, but your AC interface described 5 input terminals? Do you also have 5 output terminals, or is there just one, mapping to the one AS interface? -- Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx> Providenza & Boekelheide, Inc.