USB Device Class Definition for Audio Devices
Release 1.0 March 18, 1998 116
Offset Field Size Value Description
5 bDeviceSubClass 1 0x00 Unused.
6 bDeviceProtocol 1 0x00 Unused.
7 bMaxPacketSize0 1 0x08 8 bytes.
8 idVendor 2 0xXXXX Vendor ID.
10 idProduct 2 0xXXXX Product ID.
12 bcdDevice 2 0xXXXX Device Release Code.
14 iManufacturer 1 0x01 Index to string descriptor that contains
the string <Your Name> in Unicode.
15 iProduct 1 0x02 Index to string descriptor that contains
the string <Your Product Name> in
Unicode.
16 iSerialNumber 1 0x00 Unused.
17 bNumConfiguration
s
1 0x01 One configuration.
C.3.2 Configuration Descriptor
Table C-2: USB Telephone Configuration Descriptor
Offset Field Size Value Description
0 bLength 1 0x09 Size of this descriptor, in bytes.
1 bDescriptorType 1 0x02 CONFIGURATION descriptor.
2 wTotalLength 2 0x00XX Length of the total configuration block,
including this descriptor, in bytes.
4 bNumInterfaces 1 0x03 Three interfaces
5 bConfigurationValue 1 0x01 ID of this configuration
6 iConfiguration 1 0x00 Unused.
7 bmAttributes 1 0x60 Self Powered Remote Wakeup capable.
8 MaxPower 1 0x00 Not applicable.
C.3.3 AudioControl Interface Descriptor
The AudioControl interface describes the device structure and is used to manipulate the Audio Controls.
USB Device Class Definition for Audio Devices
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C.3.3.1 Standard AC Interface Descriptor
The AudioControl interface has no dedicated endpoints associated with it. It uses the default pipe
(endpoint 0) for all communication purposes. Class-specific AudioControl Requests are sent using the
default pipe. There is no Status Interrupt endpoint provided.
Table C-3: USB Telephone Standard AC Interface Descriptor
Offset Field Size Value Description
0 bLength 1 0x09 Size of this descriptor, in bytes.
1 bDescriptorType 1 0x04 INTERFACE descriptor.
2 bInterfaceNumber 1 0x00 Index of this interface.
3 bAlternateSetting 1 0x00 Index of this setting.
4 bNumEndpoints 1 0x00 0 endpoints.
5 bInterfaceClass 1 0x01 AUDIO.
6 bInterfaceSubclass 1 0x01 AUDIO_CONTROL.
7 bInterfaceProtocol 1 0x00 Unused.
8 iInterface 1 0x00 Unused.
C.3.3.2 Class-specific Interface Descriptor
The Class-specific AC interface descriptor is always headed by a Header descriptor that contains general
information about the AudioControl interface. It contains all the pointers needed to describe the Audio
Interface Collection, associated with the described audio function.
Table C-4: USB Telephone Class-specific Interface Descriptor
Offset Field Size Value Description
0 bLength 1 0x0A Size of this descriptor, in bytes.
1 bDescriptorType 1 0x24 CS_INTERFACE.
2 bDescriptorSubtype 1 0x01 HEADER subtype.
3 bcdADC 2 0x0100 Revision of class specification - 1.0
5 wTotalLength 2 0x0064 Total size of class specific descriptors.
7 bInCollection 1 0x02 Number of streaming interfaces
8 baInterfaceNr(1) 1 0x01 AudioStreaming interface 1 belongs to
this AudioControl interface.
9 BaInterfaceNr(2) 1 0x02 AudioStreaming interface 2 belongs to
this AudioControl interface.
USB Device Class Definition for Audio Devices
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C.3.3.3 Input Terminal Descriptor (ID1)
This descriptor describes the Input Terminal that represents the analog telephone line input. The audio
channel cluster on the single Output Pin contains a single logical channel (bNrChannels=1) and there is
no spatial location associated with this mono channel (wChannelConfig=0x0000).
This is the input part of a bi-directional Terminal and therefore has an associated Output Terminal (ID4).
Table C-5: USB Telephone Input Terminal Descriptor (ID1)
Offset Field Size Value Description
0 bLength 1 0x0C Size of this descriptor, in bytes.
1 bDescriptorType 1 0x24 CS_INTERFACE.
2 bDescriptorSubtype 1 0x02 INPUT_TERMINAL subtype.
3 bTerminalID 1 0x01 ID of this Terminal.
4 wTerminalType 2 0x0501 Terminal is Phone Line In.
6 bAssocTerminal 1 0x04 Associated with Phone Line Out
Terminal.
7 bNrChannels 1 0x01 One channel.
8 wChannelConfig 2 0x0000 Mono sets no position bits.
10 iChannelNames 1 0x00 Unused.
11 iTerminal 1 0x00 Unused.
C.3.3.4 Input Terminal Descriptor (ID2)
This descriptor describes the telephone handset input microphone. The audio channel cluster on the single
Output Pin contains a single logical channel (bNrChannels=1) and there is no spatial location associated
with this mono channel (wChannelConfig=0x0000).
This is the input part of a bi-directional Terminal and therefore has an associated Output Terminal (ID5).
Table C-6: USB Telephone Input Terminal Descriptor (ID2)
Offset Field Size Value Description
0 bLength 1 0x0C Size of this descriptor, in bytes.
1 bDescriptorType 1 0x24 CS_INTERFACE.
2 bDescriptorSubtype 1 0x02 INPUT_TERMINAL subtype.
3 bTerminalID 1 0x02 ID of this Terminal.
4 wTerminalType 2 0x0401 Terminal is Handset In.
6 bAssocTerminal 1 0x05 Associated with Handset Out Terminal.
USB Device Class Definition for Audio Devices
Release 1.0 March 18, 1998 119
Offset Field Size Value Description
7 bNrChannels 1 0x01 One channel.
8 wChannelConfig 2 0x0000 Mono sets no position bits.
10 iChannelNames 1 0x00 Unused.
11 iTerminal 1 0x04 Unused.
C.3.3.5 Input Terminal Descriptor (ID3)
This descriptor describes the USB stream from the Host to the telephone set. The audio channel cluster on
the single Output Pin contains a single logical channel (bNrChannels=1) and there is no spatial location
associated with this mono channel (wChannelConfig=0x0000).
This is the input part of a bi-directional Terminal and therefore has an associated Output Terminal (ID6).
Table C-7: USB Telephone Input Terminal Descriptor (ID3)
Offset Field Size Value Description
0 bLength 1 0x0C Size of this descriptor, in bytes.
1 bDescriptorType 1 0x24 CS_INTERFACE.
2 bDescriptorSubtype 1 0x02 INPUT_TERMINAL subtype.
3 bTerminalID 1 0x03 ID of this Terminal.
4 wTerminalType 2 0x0101 Terminal is USB Streaming In.
6 bAssocTerminal 1 0x06 Associated with USB Streaming out
Terminal.
7 bNrChannels 1 0x01 One channel.
8 wChannelConfig 2 0x0000 Mono sets no position bits.
10 iChannelNames 1 0x00 Unused.
11 iTerminal 1 0x05 Unused.
C.3.3.6 Output Terminal Descriptor (ID4)
This descriptor describes the Output Terminal that represents the analog telephone line output. The audio
channel cluster on the single Input Pin contains a single logical channel.
This is the output part of a bi-directional Terminal and therefore has an associated Input Terminal (ID1).
Table C-8: USB Telephone Output Terminal Descriptor (ID4)
Offset Field Size Value Description
0 bLength 1 0x09 Size of this descriptor, in bytes.
USB Device Class Definition for Audio Devices
Release 1.0 March 18, 1998 120
Offset Field Size Value Description
1 bDescriptorType 1 0x24 CS_INTERFACE.
2 bDescriptorSubtype 1 0x03 OUTPUT_TERMINAL subtype.
3 bTerminalID 1 0x04 ID of this Terminal.
4 wTerminalType 2 0x0501 Terminal is Phone Line Out.
6 bAssocTerminal 1 0x01 Associated with Phone Line In Terminal.
7 bSourceID 1 0x07 From Phone Line Selector Unit.
8 iTerminal 1 0x06 Unused.
C.3.3.7 Output Terminal Descriptor (ID5)
This descriptor describes the telephone handset output earpiece. The audio channel cluster on the single
Input Pin contains a single logical channel.
This is the output part of a bi-directional Terminal and therefore has an associated Input Terminal (ID2).
Table C-9: USB Telephone Output Terminal Descriptor (ID5)
Offset Field Size Value Description
0 bLength 1 0x09 Size of this descriptor, in bytes.
1 bDescriptorType 1 0x24 CS_INTERFACE.
2 bDescriptorSubtype 1 0x03 OUTPUT_TERMINAL subtype.
3 bTerminalID 1 0x05 ID of this Terminal.
4 wTerminalType 2 0x0401 Terminal is Handset Out.
6 bAssocTerminal 1 0x01 Associated with Handset In Terminal.
7 bSourceID 1 0x08 From Handset Selector Unit.
8 iTerminal 1 0x00 Unused.
C.3.3.8 Output Terminal Descriptor (ID6)
This descriptor describes the USB stream from the telephone set to the Host. The audio channel cluster on
the single Input Pin contains a single logical channel.
This is the output part of a bi-directional Terminal and therefore has an associated Input Terminal (ID3).
Table C-10: USB Telephone Output Terminal Descriptor (ID6)
Offset Field Size Value Description
0 bLength 1 0x09 Size of this descriptor, in bytes.
最終更新：2011年05月02日 03:36
