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USB classes in more detail
This page described the various USB classes in more detail. Each class is further divided into sub-classes, and each sub-class is further divided into protocols. The complete class is often defined as <class>_<subclass>_<protocol>, e.g. 7_1_2 (bi-directional printer).
Class 1 - Audio
This class contains audio devices such as amplifiers, receivers, music instruments, recording and play-back devices. At present, there is no support for these type of devices on RISC OS.

  Class Description RISC OS
1_1_0 Audio Control -
1_2_0 Audio Streaming -
1_3_0 MIDI Streaming -

Class 2 - Communication Device Class
This class contains communication devices such as Analog Modems, ISDN modems, Telephone sets, Ethernet control, ATM control, etc. In practice however, most communication devices have a vendor specific interface.

  Class Description RISC OS
2 Communication device -

Class 3 - Human Interface Devices
This class contains Human Interface Devices, such as Mouse, Keyboard, Tablet, Joystick, Barcode reader, etc. It is by far the most popular USB class. Basic support for keyboard and mouse is present in the RISC OS kernel, but for additional features, our USBHID module is recommended.

  Class Description RISC OS
3 HID Class device (Human Interface device) See below
3_1_1 Keyboard USSBHID
3_1_2 Mouse USBHID
3_1_2 Tablet In progress
3_1_2 Touch screen In progress
3 Joystick USBHID
3 Barcode reader USBHID

 Overview of supported devices in the Human Interface Device class (HID)
 Get the latest USB HID Class Driver

Class 6 - Image
  Class Description RISC OS
6 Document Scanner Optional
6 Camera -
6_1_1 iPhone, Picture Transfer Protocol PIMA 15470 -
6_1_1 iPhone, Picture Transfer Protocol PIMA 15470 -

Class 7 - Printers
RISC OS contains native support for most standard printers connected via USB. This includes old printers with a Centronics interface that are connected via a special dongle.

  Class Description RISC OS
7_1_1 Unidirectional printer Native
7_1_2 Bi-directional printer (the most common one today) Native
7_1_3 IEEE 1284.4 compatible printer -

 Overview of supported devices in the Printing Class

Class 8 - Mass Storage
This class contains nearly all storage devices, such as harddiscs, card readers, flash drives, external floppy drives and even some cameras. RISC OS currently only supports class 8_6 (SCSI), but this includes nearly all current storage devices found on the market today.

  Class Description RISC OS
8_1 RBC (Reduced Block Commands) -
8_2 ATAPI: typically a CD or DVD -
8_3 QIC-157: typically a tape device -
8_4 UFI: typically a floppy disc drive (FDD) -
8_5 SFF-8070i: typically a floppy disc drive FDD -
8_6 SCSI: devices using a SCSI command set Native

 Overview of supported devices in the Mass Storage Class

Class 9 - HUB
This class is the most common one as it will be found on virtually every computer supporting USB. Any interface card with more than one USB port on it contains a Hub and further Hubs can be cascaded to allow more devices to be connected.

  Class Description RISC OS
9 Hub (the first Hub is inside the computer) Native

 Overview of supported USB HUBs

Class 10 - Data Interface Class
This class contains a wide range of devices that can be used for streaming data, such as webcams. Many different protocols and transfer modes exist in this class. Unfortunately, most data streaming devices used the vendor specific class.

  Class Description RISC OS
10 Data Interface -
10_255_0 Webcam (many different versions exist) -

Class 11 - Chip card / Smart card
  Class Description RISC OS
11 Smart cards -

Class 255 - Vendor-Specific
This class contains devices that do not fall into any other class and devices with the vendor-specific interface and/or protocol. Support for such devices under RISC OS is very unlikely, as it requires the cooperation of the manufacturer. Her are some examples of devices we have seen:

  Class Description RISC OS
255 Serial RS232 interface -
255 Peer-to-peer network -

Further information

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Last changed: Thursday, 03 November 2016 - 11:01 CET.
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