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In the list of USB classes, in addition to the obvious things (like "Printer", "Hub" and "Storage"), there are also such things like "Audio", "Video", "Audio/Video" and "Billboard".

But there is no "Mouse" class and "Keyboard" class. This devices are inclueded to "HID" class. But not only this. I work with the FT260Q (USB-I2C/UART) bridge. Unexpected, but it is a HID device. And for work it needs the LibFT260-vXXX.dll. In other word it needs a driver.

I know that there is a standard drivers for HID-class devices to work with mouses and keyboards. And there is no standard drivers for Vendor secific class devices by definition. But as I say there is many HID-class devices which need drivers.

And I understand that the questions "Why HID functionality is so large?"/"What is the difference between a custom device with HID class and device with "Vendor specific" class?"/"Why are mouses and keyboards combined in one class with other custom devices?" are partially opinion based.

So I ask, are there any useful points of such a large functionality of USB HID class? If there is no such points is this an example of the imperfection of the standard?

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    \$\begingroup\$ This doesn't answer your question BUT this fascinating document is liable to be of interest [USB HID Usage Tables - 10/28/2004 - Version 1.12 ](usb.org/sites/default/files/documents/hut1_12v2.pdf) 168 pages! \$\endgroup\$
    – Russell McMahon
    Commented Nov 17, 2022 at 11:16
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    \$\begingroup\$ MICROSOFT AND HID Usage table V1.2 March 2022 ! here - 432 pages. And Apple weighs in \$\endgroup\$
    – Russell McMahon
    Commented Nov 17, 2022 at 11:21
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    \$\begingroup\$ They may grok USB BUT they do not know how motorcycles work :-). They say: "A steering control, held in both hands, for a motorcycle or bicycle. A zero output value indicates that the direction of travel is straight ahead. Pulling back on the right side turns the vehicle to the right and generates a positive output. Pulling back on the left side turns the vehicle to the left and generates a negative output." --> NO, it definitely does not!!! - From page 69 here \$\endgroup\$
    – Russell McMahon
    Commented Nov 17, 2022 at 11:26
  • \$\begingroup\$ Afaik "there is no standard drivers for Vendor secific class devices by definition" is not correct. HID drivers are always "built-in" to the OS (assuming the OS supports HID) and vendor-specific HID devices do not need vendor drivers. The OS may not know what to do with a vendor-specific HID device, but an application running in that OS can make standard OS HID calls to interact with this vendor-specific HID device without the user having to install any drivers at all. \$\endgroup\$
    – brhans
    Commented Nov 17, 2022 at 13:35

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HID is often abused because most operating systems (that means Windows) need drivers for vendor-specific devices, but not for HID devices. It's not the intention - it's a hack.

Some cellphones and cameras used to pretend to be CD drives so that you could install the driver from the fake CD drive after plugging in the cellphone/camera, instead of finding the actual CD and putting it in your actual drive. This is the same kind of idea. The device pretending to be something it's not, to trick the operating system to improve the user experience.

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