PORTS Forum

Ports and Interfaces => USB => Topic started by: jb on July 07, 2020, 05:28:38 pm

Title: Multiple endpoints for an audio interface?
Post by: jb on July 07, 2020, 05:28:38 pm

On http://www.usbmadesimple.co.uk/ums_4.htm it says:

   

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For example a VOIP phone might have one audio class interface with 2 endpoints for transferring audio in each direction

however, the USB Audio spec (1.0/2.0/3.0) says:

   

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Each AudioStreaming interface can have at most one isochronous data endpoint.

So is this incorrect?  The VoIP in and out streams would need to be separate interfaces?

https://docs.microsoft.com/en-us/windows-hardware/drivers/audio/usb-2-0-audio-drivers similarly says:

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Each non-zero alternate setting must specify an isochronous data endpoint, and optionally a feedback endpoint.

Title: Re: Multiple endpoints for an audio interface?
Post by: Jan Axelson on July 07, 2020, 06:03:26 pm

The spec is the final word so I believe the answer is yes.