[alsa-devel] Digidesign Mbox 2 Mini

Mark Hills mark at pogo.org.uk
Sun Oct 19 15:52:55 CEST 2008


I have been trying to use a Digidesign Mbox 2 Mini (USB) without success, 
but with some positive signs.

The device is detected. From the software side, playback appears to work 
-- both aplay and mplayer push audio to somewhere (no crashes, and at the 
correct rate). But there is no sound from any of the outputs.

Recording is not so good. It does not error or crash, but arecord hangs 
and creates a 44 byte file containing the WAV header. In a test program, 
snd_pcm_readi() does not return and strace waits on poll().

I found two threads on alsa-devel referring to the Mbox interfaces (a 
different model to the one I am using though; different ID):

   http://mailman.alsa-project.org/pipermail/alsa-devel/2007-November/004394.html
   http://www.mail-archive.com/alsa-devel@lists.sourceforge.net/msg12273.html

In the second one, which is from 2004, Clemens says:

> Strange.  But having two endpoints in one interface is not what the 
> driver was written for.  I think part of the driver needs to be 
> rewritten before this device can work.

Now this is a while ago, with a different interface. But the Mbox 2 mini 
also has two endpoints in one interface (see attached lsusb output), and I 
seem to be getting considerably more out of the interface than the 
original poster.

So is it possible that the driver is now successfully getting audio to the 
playback endpoint only, and just needs some kind of mixer device control 
(or similar) for playback to work? Or is the 'success' with aplay/mplayer 
misleading -- how far off working is this?

Thanks,

-- 
Mark
-------------- next part --------------

Bus 005 Device 005: ID 0dba:3000  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x0dba 
  idProduct          0x3000 
  bcdDevice            1.40
  iManufacturer           1 Digidesign
  iProduct                2 Mbox 2 
  iSerial                 1 Digidesign
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          646
    bNumInterfaces          7
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              500mA
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass       254 Application Specific Interface
      bInterfaceSubClass      1 Device Firmware Update
      bInterfaceProtocol      0 
      iInterface              0 
      ** UNRECOGNIZED:  07 21 05 ff ff 08 00
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
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      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              2 Mbox 2 
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength           96
        bInCollection           4
        baInterfaceNr( 0)       2
        baInterfaceNr( 1)       3
        baInterfaceNr( 2)       4
        baInterfaceNr( 3)       5
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             5
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             6
        wTerminalType      0x0601 Analog Connector
        bAssocTerminal          0
        bSourceID               5
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             7
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             8
        wTerminalType      0x0601 Analog Connector
        bAssocTerminal          0
        bSourceID               7
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0601 Analog Connector
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             2
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               1
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0601 Analog Connector
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             4
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               3
        iTerminal               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       2
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
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        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           5
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
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        bSubframeSize           3
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        bSamFreqType            0 Continuous
        tLowerSamFreq        8000
        tUpperSamFreq       48000
      Endpoint Descriptor:
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          Transfer Type            Isochronous
          Synch Type               Asynchronous
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        bInterval               1
        bRefresh                0
        bSynchAddress         131
        AudioControl Endpoint Descriptor:
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          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
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        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
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          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0003  1x 3 bytes
        bInterval               1
        bRefresh                2
        bSynchAddress           0
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       3
      bNumEndpoints           2
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      bInterfaceSubClass      2 Streaming
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        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           5
        bDelay                  1 frames
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      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             2
        bSubframeSize           3
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        bSamFreqType            0 Continuous
        tLowerSamFreq        8000
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          Usage Type               Data
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        bSynchAddress         131
        AudioControl Endpoint Descriptor:
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          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
      Endpoint Descriptor:
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        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0003  1x 3 bytes
        bInterval               1
        bRefresh                2
        bSynchAddress           0
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       2
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
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        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           7
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
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        bSubframeSize           3
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        bSamFreqType            0 Continuous
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      Endpoint Descriptor:
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          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
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        bInterval               1
        bRefresh                0
        bSynchAddress         132
        AudioControl Endpoint Descriptor:
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          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
      Endpoint Descriptor:
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        bEndpointAddress     0x84  EP 4 IN
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          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
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        bInterval               1
        bRefresh                2
        bSynchAddress           0
    Interface Descriptor:
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      bAlternateSetting       3
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      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           7
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             2
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        bSamFreqType            0 Continuous
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      Endpoint Descriptor:
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          Transfer Type            Isochronous
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          Usage Type               Data
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        bInterval               1
        bRefresh                0
        bSynchAddress         132
        AudioControl Endpoint Descriptor:
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          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
      Endpoint Descriptor:
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        bDescriptorType         5
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        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
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        bInterval               1
        bRefresh                2
        bSynchAddress           0
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        3
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      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
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        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
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        bDescriptorSubtype      2 (FORMAT_TYPE)
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        bSamFreqType            0 Continuous
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        tUpperSamFreq       48000
      Endpoint Descriptor:
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          Transfer Type            Isochronous
          Synch Type               Synchronous
          Usage Type               Data
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        bSynchAddress           0
        AudioControl Endpoint Descriptor:
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          bDescriptorSubtype      1 (EP_GENERAL)
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            Sampling Frequency
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          wLockDelay              0 Undefined
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      bDescriptorType         4
      bInterfaceNumber        4
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      bNumEndpoints           0
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      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
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    Interface Descriptor:
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      bInterfaceSubClass      2 Streaming
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        bDescriptorType        36
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        bDelay                  1 frames
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        bDescriptorSubtype      2 (FORMAT_TYPE)
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        tUpperSamFreq       48000
      Endpoint Descriptor:
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        AudioControl Endpoint Descriptor:
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          wLockDelay              0 Undefined
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      bInterfaceNumber        4
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      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
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      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
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        bBitResolution         24
        bSamFreqType            0 Continuous
        tLowerSamFreq        8000
        tUpperSamFreq       48000
      Endpoint Descriptor:
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          Synch Type               Synchronous
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        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
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          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        5
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        5
      bAlternateSetting       2
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           4
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
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        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
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        bSubframeSize           3
        bBitResolution         24
        bSamFreqType            0 Continuous
        tLowerSamFreq        8000
        tUpperSamFreq       48000
      Endpoint Descriptor:
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          Transfer Type            Isochronous
          Synch Type               Asynchronous
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        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
    Interface Descriptor:
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      bDescriptorType         4
      bInterfaceNumber        5
      bAlternateSetting       3
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
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        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           4
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
        bLength                14
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
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        bBitResolution         24
        bSamFreqType            0 Continuous
        tLowerSamFreq        8000
        tUpperSamFreq       48000
      Endpoint Descriptor:
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        bDescriptorType         5
        bEndpointAddress     0x86  EP 6 IN
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          Transfer Type            Isochronous
          Synch Type               Synchronous
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        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        6
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               0
Device Status:     0x0000
  (Bus Powered)


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