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Home > Developers > Defined 1.0 Class Codes

USB Class Codes                    

August 11, 2014


USB defines class code information that is used to identify a device’s functionality and to nominally load a device driver based on that functionality. The information is contained in three bytes with the names Base Class, SubClass, and Protocol. (Note that ‘Base Class’ is used in this description to identify the first byte of the Class Code triple. That terminology is not used in the USB Specification). There are two places on a device where class code information can be placed.One place is in the Device Descriptor, and the other is in Interface Descriptors. Some defined class codes are allowed to be used only in a Device Descriptor, others can be used in both Device and Interface Descriptors, and some can only be used in Interface Descriptors. The table below shows the currently defined set of  Base Class values, what the generic usage is, and where that Base Class can be used (either Device or Interface Descriptors or both).


Base Class

Descriptor Usage

Description

00h

Device

Use class information in the Interface Descriptors

01h

Interface

Audio  

02h

Both

Communications and CDC Control

03h

Interface

HID (Human Interface Device)

05h

Interface

Physical

06h

Interface

Image

07h

Interface

Printer

08h

Interface

Mass Storage

09h

Device

Hub

0Ah

Interface

CDC-Data

0Bh

Interface

Smart Card

0Dh

Interface

Content Security

0Eh

Interface

Video

0Fh

Interface

Personal Healthcare

10h

Interface

Audio/Video Devices

11h

Device

Billboard Device Class

DCh

Both

Diagnostic Device

E0h

Interface

Wireless Controller

EFh

Both

Miscellaneous

FEh

Interface

Application Specific

FFh

Both

Vendor Specific

 

Base Class 00h (Device)

This base class is defined to be used in Device Descriptors to indicate that class information should be determined from the Interface Descriptors in the device. There is one class code definition in this base class.  All other values are reserved.

 

This value is also used in Interface Descriptors to indicate a null class code triple.

 

Base Class

SubClass

Protocol

Meaning

00h

00h

00h

Use class code info from Interface Descriptors

 


Base Class 01h (Audio)

This base class is defined for Audio capable devices that conform to the Audio Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes may only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

01h

xxh

xxh

Audio device

 

 

Base Class 02h (Communications and CDC Control)

 

This base class is defined for devices that conform to the Communications Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved.  Note that the Communication Device Class spec requires some class code values (triples) to be used in Device Descriptors and some to be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

02h

xxh

xxh

Communication device class

 

Base Class 03h (HID – Human Interface Device)

This base class is defined for devices that conform to the HID Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values.   Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

03h

xxh

xxh

HID device class

 

Base Class 05h (Physical)

This base class is defined for devices that conform to the Physical Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values.  Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

05h

xxh

xxh

Physical device class

 

 

Base Class 06h (Still Imaging)

This base class is defined for devices that conform to the Imaging Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values.   Values outside of that defined spec are reserved.

 

Base Class

SubClass

Protocol

Meaning

06h

01h

01h

Still Imaging device

 

 

Base Class 07h (Printer)

This base class is defined for devices that conform to the Printer Device Class Specification found on the USB-IF website.  That specification defines the usable set of SubClass and Protocol values.  Values outside of that defined spec are reserved.  These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

07h

xxh

xxh

Printer device

 

 

Base Class 08h (Mass Storage)

This base class is defined for devices that conform to the Mass Storage Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

08h

xxh

xxh

Mass Storage device

 

 

Base Class 09h (Hub)

This base class is defined for devices that are USB hubs and conform to the definition in the USB specification.  That specification defines the complete triples as shown below.  All other values are reserved.  These class codes can only be used in Device Descriptors.

 

Base Class

SubClass

Protocol

Meaning

09h

00h

00h

Full speed Hub

01h

Hi-speed hub with single TT

02h

Hi-speed hub with multiple TTs

 

 

Base Class 0Ah (CDC-Data)

This base class is defined for devices that conform to the Communications Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values.Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

0Ah

xxh

xxh

CDC data device

 

 

Base Class 0Bh (Smart Card)

This base class is defined for devices that conform to the Smart Card Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values.Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

0Bh

xxh

xxh

Smart Card device

 

 

Base Class 0Dh (Content Security)

This base class is defined for devices that conform to the Content Security Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

0Dh

00h

00h

Content Security device

 

 

Base Class 0Eh (Video)

This base class is defined for devices that conform to the Video Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

0Eh

xxh

xxh

Video device

 

 

Base Class 0Fh (Personal Healthcare)

This base class is defined for devices that conform to the Personal Healthcare Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes should only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

0Fh

xxh

xxh

Personal Healthcare device

 

 

Base Class 10h (Audio/Video Devices)

The USB Audio/Video (AV) Device Class Definition describes the methods used to communicate with devices or functions embedded in composite devices that are used to manipulate audio, video, voice, and all image- and sound-related functionality. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors. 

 

Base Class

SubClass

Protocol

Meaning

10h

01h

 

02h

 

03h 

 

00h

Audio/Video Device – AVControl Interface

00h

Audio/Video Device – AVData Video Streaming Interface

00h

Audio/Video Device – AVData Audio Streaming Interface

 


Base Class 11h (Billboard Device)

This base class is defined for devices that conform to the Billboard Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes can only be used in Device Descriptors.

 

Base Class

SubClass

Protocol

Meaning

11h

00h

00h

Billboard Device


 

Base Class DCh (Diagnostic Device)

This base class is defined for devices that diagnostic devices. There is currently only one value defined. All other values are reserved. This class code can be used in Device or Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

DCh

01h

01h

USB2 Compliance Device.  Definition for this device can be found at http://www.intel.com/technology/usb/spec.htm

 

 

Base Class E0h (Wireless Controller)

This base class is defined for devices that are Wireless controllers. Values not shown in the table below are reserved. These class codes are to be used in Interface Descriptors, with the exception of the Bluetooth class code which can also be used in a Device Descriptor.


Base Class

SubClass

Protocol

Meaning

E0h

01h

01h

Bluetooth Programming Interface.  Get specific information from www.bluetooth.com.

02h

UWB Radio Control Interface.  Definition for this is found in the Wireless USB Specification in Chapter 8.

03h

Remote NDIS.  Information can be found at: http://www.microsoft.com/windowsmobile/mobileoperators/default.mspx

04h

 

Bluetooth AMP Controller. Get specific information from www.bluetooth.com.

2h

01h

Host Wire Adapter Control/Data interface.  Definition can be found in the Wireless USB Specification in Chapter 8.

02h

Device Wire Adapter Control/Data interface.  Definition can be found in the Wireless USB Specification in Chapter 8.

03h

Device Wire Adapter Isochronous interface.  Definition can be found in the Wireless USB Specification in Chapter 8.

 

Base Class EFh (Miscellaneous)

This base class is defined for miscellaneous device definitions. Values not shown in the table below are reserved.  The use of these class codes (Device or Interface descriptor) are specifically annotated in each entry below.

 

Base Class

SubClass

Protocol

Meaning

EFh

01h

01h

Active Sync device. This class code can be used in either Device or Interface Descriptors. Contact Microsoft for more information on this class.

02h

Palm Sync. This class code can be used in either Device or Interface Descriptors.

02h

01h

Interface Association Descriptor. The usage of this class code triple is defined in the Interface Association Descriptor ECN that is provided on www.usb.org . This class code may only be used in Device Descriptors.

02h

Wire Adapter Multifunction Peripheral programming interface. Definition can be found in the Wireless USB Specification in Chapter 8. This class code may only be used in Device Descriptors

03h

01h

Cable Based Association Framework. This is defined in the Association Model addendum to the Wireless USB specification. This class code may only be used in Interface Descriptors.

04h

01h

RNDIS over Ethernet.

Connecting a host to the Internet via Ethernet mobile device. The device appears to the host as an Ethernet gateway device.

This class code may only be used in Interface Descriptors.

02h

RNDIS over WiFi.

Connecting a host to the Internet via WiFi enabled mobile device.  The device represents itself to the host as an 802.11 compliant network device.

This class code may only be used in Interface Descriptors.

03h

RNDIS over WiMAX

Connecting a host to the Internet via WiMAX enabled mobile device.  The device is represented to the host as an 802.16 network device.

This class code may only be used in Interface Descriptors.

04h

RNDIS over WWAN

Connecting a host to the Internet via a device using mobile broadband, i.e. WWAN (GSM/CDMA).

This class code may only be used in Interface Descriptors.

05h

RNDIS for Raw IPv4

Connecting a host to the Internet using raw IPv4 via non-Ethernet mobile device.  Devices that provide raw IPv4, not in an Ethernet packet, may use this form to in lieu of other stock types.

This class code may only be used in Interface Descriptors.

06h

RNDIS for Raw IPv6

Connecting a host to the Internet using raw IPv6 via non-Ethernet mobile device.  Devices that provide raw IPv6, not in an Ethernet packet, may use this form to in lieu of other stock types.

This class code may only be used in Interface Descriptors.

07h

RNDIS for GPRS

Connecting a host to the Internet over GPRS mobile device using the device’s cellular radio

05h

00h

USB3 Vision Control Interface

Machine Vision Device conforming to the USB3 Vision specification. This standard covers cameras and other related devices that are typically used in machine vision, industrial, and embedded applications.

Reference: http://visiononline.org/

This class code may only be used in Interface Descriptors.

01h

USB3 Vision Event Interface

02h

USB3 Vision Streaming Interface

 

Base Class FEh (Application Specific)

This base class is defined for devices that conform to several class specifications found on the USB-IF website.  That specification defines the usable set of SubClass and Protocol values.  Values outside of that defined spec are reserved.  These class codes can only be used in Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

FEh

01h

01h

Device Firmware Upgrade.  Device class definition provided on www.usb.org .

02h

00h

IRDA Bridge device.  Device class definition provided on www.usb.org .

03h

00h

USB Test and Measurement Device.  Definition provided in the USB Test and Measurement Class spec found on www.usb.org .

01h

USB Test and Measurement Device conforming to the USBTMC USB488 Subclass Specification found on www.usb.org.

 

 

Base Class FFh (Vendor Specific)

This base class is defined for vendors to use as they please.  These class codes can be used in both Device and Interface Descriptors.

 

Base Class

SubClass

Protocol

Meaning

FFh

xxh

xxh

Vendor specific