USB vid and PID, and classification (CLASS,SUBCLASS,PROTOCOL)

The USB (Universal Serial bus, Universal Serial Bus) protocol stipulates that all USB devices have vid (Vendor ID, vendor identification number) and PID (product ID, identification code). The vid is submitted by the supplier to USB-IF (Implementers forum, the application forums). Each vendor's vid is unique and the PID is at the supplier's discretion. The host uses VID and PID to identify different devices, depending on them (and the version number of the device), to load or install the appropriate driver for the device. The length of the vid and PID is two bytes.
Common major suppliers of vid and PID, can be found here: http://www.linux-usb.org/usb.ids

USB defines the kind of code information that is used to identify the functionality of the device, based on these functions, to load the device driver. This information is contained in 3 bytes named base class, subclass, and protocol (note: "Base class" is used in this article to identify the first byte of a three-byte kind code, which is not used in the USB specification). There are two places in the device where you can store kind of code information, one is a device descriptor, and the other is an interface descriptor. Already defined types of code, some can only be used in the device descriptor, some can only be used in the interface descriptor, and some of the two descriptions character are available. The following table gives a set of values for the base class that is now set, what the general usage is, and where the base class is used (device descriptor or interface descriptor).
For specific definitions see USB official website: Http://www.usb.org/developers/defined_class
Definitions of each category see: Http://www.usb.org/developers/devclass_docs

Base Class	Descriptor Usage	Description
00h	Device	Use class information in the Interface descriptors type information defined in interface descriptor
01h	Interface	Audio Devices
02h	Both	Communications & CDC Communications equipment ( mobile , Class_&subclass_ &prot_)
03h	Interface	HID (Human Interface device) human-machine interface devices
05h	Interface	Physical physical Equipment
06h	Interface	Image Imaging Device (possibly iphone, class_06&subclass_01&prot_01)
07h	Interface	Printer Printer
08h	Interface	Mass Storage mass Storage (may be mobile , class_08&subclass_06&prot_50)
09h	Device	Hub Hub
0Ah	Interface	Cdc-data Communication equipment ( mobile phone , Class_0A&subclass_ &prot_xx)
0Bh	Interface	Smart Card Smart Card
0Dh	Interface	Content Security Device
0Eh	Interface	Video Device (webcam, class_0e&subclass_03&prot_00)
0Fh	Interface	Personal Healthcare Personal Health Equipment
10h	Interface	Audio/video Devices Audio/video equipment
DCh	Both	Diagnostic Device Diagnostic Devices (USB2 compatible devices)
e0h	Interface	Wireless Controller Wireless Controllers (Bluetooth devices, etc.)
Efh	Both	Miscellaneous miscellaneous (Activesync,palmsync, various associations, etc.)
FEh	Interface	Application Specific application proprietary specification (firmware upgrade, infrared, USB test and measurement, etc.)
FFh	Both	Vendor Specific supplier Custom specification ( mobile , CLASS_FF&SUBCLASS_FF&PROT_FF)

USB vid and PID, and classification (CLASS,SUBCLASS,PROTOCOL)