USB Device Classes

A USB Device Class is a groups of devices or interfaces with similar attributes or services. USB Class is mainly used to describe the manner in which an interface communicates with the host including both data and control mechanisms. The class information is used by the host to identify and load the required drivers for specific interfaces/devices, to manage interface connectivity, and to manage the capabilities provided by the interface.

A USB Class Specification defines the requiremenets of a USB Class. The Class Specification is used by both firmware developers and host software developers (device driver developers) to agree upon certain rules while developing a USB device. The device drivers that cover all features of a device class is known as Class Drivers. These drivers can be used by any kind of device that falls in a particular device class.

The Class Drivers are developed by Operating System or third party software vendors, as well as by manufacturers supporting multiple devices which fall in the same device class.

USB-IF is responsible for defining and maintaining Device Class Specifications.