UAC规范（USB音频）
UAC 终端类型
USB Terminal Types
These Terminal Types describe Terminals that handle signals carried over the USB, usually through
isochronous pipes. These Terminal Types are valid for both Input and Output Terminals.
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| USB Undefined | 0x0100 | I/O | USB Terminal, undefined Type. |
| USB streaming | 0x0101 | I/O | A Terminal dealing with a signal carried over an endpoint in an AudioStreaming interface. The AudioStreaming interface descriptor points to the associated Terminal through the bTerminalLink field. |
| USB vendor specific | 0x01FF | I/O | A Terminal dealing with a signal carried over a vendor-specific interface. The vendor-specific interface descriptor must contain a field that references the Terminal. |
Input Terminal Types
These Terminal Types describe Terminals that are designed to record sounds. They either are physically
part of the audio function or can be assumed to be connected to it in normal operation. These Terminal
Types are valid only for Input Terminals
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| Input Undefined | 0x0200 | I | Input Terminal, undefined Type. |
| Microphone | 0x0201 | I | A generic microphone that does not fit under any of the other classifications. |
| Desktop microphone | 0x0202 | I | A microphone normally placed on the desktop or integrated into the monitor. |
| Personal microphone | 0x0203 | I | A head-mounted or clip-on microphone. |
| Omni-directional microphone | 0x0204 | I | A microphone designed to pick up voice from more than one speaker at relatively long ranges. |
| Microphone array | 0x0205 | I | An array of microphones designed for directional processing using host-based signal processing algorithms. |
| Processing microphone array | 0x0206 | I | An array of microphones with an embedded signal processor. |
Output Terminal Types
These Terminal Types describe Terminals that produce audible signals that are intended to be heard by
the user of the audio function. They either are physically part of the audio function or can be assumed to
be connected to it in normal operation. These Terminal Types are only valid for Output Terminals. The
distinction between headphones, desktop speakers, and room speakers may be used by applications to
select different 3D signal processing algorithms
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| Output Undefined | 0x0300 | O | Output Terminal, undefined Type. |
| Speaker | 0x0301 | O | A generic speaker or set of speakers that does not fit under any of the other classifications. |
| Headphones | 0x0302 | O | A head-mounted audio output device. |
| Head Mounted Display Audio | 0x0303 | O | The audio part of a VR head mounted display. The Associated Interfaces descriptor can be used to reference the HID interface used to report the position and orientation of the HMD. |
| Desktop speaker | 0x0304 | O | Relatively small speaker or set of speakers normally placed on the desktopor integrated into the monitor. These speakers are close to the user and have limited stereo separation. |
| Room speaker | 0x0305 | O | Larger speaker or set of speakers that are heard well anywhere in the room. |
| Communication speaker | 0x0306 | O | Speaker or set of speakers designed for voice communication. |
| Low frequency effects speaker | 0x0307 | O | Speaker designed for low frequencies (subwoofer). Not capable of reproducing speech or music. |
Bi-directional Terminal Types
These Terminal Types describe an Input and an Output Terminal for voice communication that are closely
related. They should be used together for bi-directional voice communication. They may be used
separately for input only or output only. These types require two Terminal descriptors. Both have the same
type. The two Terminals are linked together through the bAssocTerminal fields in their respective
Terminal descriptors. The Associated Interfaces descriptor can be used to reference a HID interface for
conferencing functions.
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| Bi-directional Undefined | 0x0400 | I/O | Bi-directional Terminal, undefined Type. |
| Handset | 0x0401 | I/O | Hand-held bi-directional audio device. |
| Headset | 0x0402 | I/O | Head-mounted bi-directional audio device. |
| Speakerphone, no echo reduction | 0x0403 | I/O | A hands-free audio device designed for host-based echo cancellation. |
| Echo-suppressing speakerphone 0 | x0404 | I/O | A hands-free audio device with echo suppression capable of half-duplex operation. |
| Echo-canceling speakerphone | 0x0405 | I/O | A hands-free audio device with echo cancellation capable of full-duplex operation. |
Telephony Terminal Types
These Terminal Types describe Terminals that connect to the PSTN or PBX. Initiating calls and
monitoring call progress will be done through an associated interface which may be Communication, HID
or Vendor-Specific class. These Terminals are bi-directional and follow the rules for bi-directional
Terminals.
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| Telephony Undefined | 0x0500 | I/O | Telephony Terminal, undefined Type. |
| Phone line - | 0x0501 | I/O | May be an analog telephone line jack, an ISDN line, a proprietary PBX interface, or a wireless link. |
| Telephone - | 0x0502 | I/O | Device can be used as a telephone. When not in use as a telephone, handset is used as a bi-directional audio device. |
| Down Line Phone | 0x0503 | I/O | A standard telephone set connected to the device. When not in use as atelephone, it can be used as a bidirectional audio device. |
External Terminal Types
These Terminal Types describe external resources and connections that do not fit under the categories of
Input or Output Terminals because they do not necessarily translate acoustic signals to or from the user of
the computer. Most of them may be either Input or Output Terminals.
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| External Undefined | 0x0600 | I/O | External Terminal, undefined Type. |
| Analog connector | 0x0601 | I/O | A generic analog connector. |
| Digital audio interface | 0x0602 | I/O | A generic digital audio interface. |
| Line connector | 0x0603 | I/O | An analog connector at standard line levels. Usually uses 3.5mm. |
| Legacy audio connector | 0x0604 | I/O | An input connector assumed to be connected to the lineout of the legacy audio system of the host computer. Used for backward compatibility. |
| S/PDIF interface | 0x0605 | I/O | An S/PDIF digital audio interface. The Associated Interface descriptor can be used to reference an interface used for controlling special functions of this interface. |
| 1394 DA stream | 0x0606 | I/O | An interface to audio streams on a 1394 bus. |
| 1394 DV stream soundtrack | 0x0607 | I/O | An interface to soundtrack of A/V stream on a 1394 bus. |
Embedded Function Terminal Types
| Terminal Type | Code | I/O | Description |
|---|---|---|---|
| Embedded Undefined | 0x0700 | I/O | Embedded Terminal, undefined Type. |
| Level Calibration Noise Source | 0x0701 | O | Internal Noise source for level calibration (MPEG decoding, Dolby PrologicÔ, AC-3 etc.) |
| Equalization Noise | 0x0702 | O | Internal Noise source for measurements. |
| CD player | 0x0703 | I | Audio compact disc player or CD-ROM capable of audio playback. |
| DAT | 0x0704 | I/O | Digital Audio Tape. |
| DCC | 0x0705 | I/O | Digital Compact Cassette. |
| MiniDisk | 0x0706 | I/O | Minidisk player. |
| Analog Tape | 0x0707 | I/O | Analog Audio Tape. |
| Phonograph | 0x0708 | I | Analog vinyl record player. |
| VCR Audio | 0x0709 | I | Audio track of VCR. |
| Video Disc Audio | 0x070A | I Audio track of VideoDisc player. | |
| DVD Audio | 0x070B | I | Audio track of DVD player. |
| TV Tuner Audio | 0x070C | I | Audio track of TV tuner. |
| Satellite Receiver Audio | 0x070D | I | Audio track of satellite receiver. |
| Cable Tuner Audio | 0x070E | I | Audio track of cable tuner. |
| DSS Audio | 0x070F | I | Audio track of DSS receiver. |
| Radio Receiver | 0x0710 | I | AM/FM radio receiver. |
| Radio Transmitter | 0x0711 | O | AM/FM radio transmitter. |
| Multi-track Recorder | 0x0712 | I/O | A multi-track recording system. |
| Synthesizer | 0x0713 | I | Synthesizer. |
