USB class 0xff — Vendor Specific Class
Class code 0xff marks a device or interface as Vendor Specific Class. Operating systems read this value from the descriptor and bind a generic class driver, which is why most vendor specific class hardware works without a vendor driver even when the VID:PID pair is unrecognised.
How it appears on your system
$ lsusb -v
bInterfaceClass 255 Vendor Specific ClassWindows exposes the same value in the compatible IDs list as USB\Class_FF, extended with &SubClass_xx&Prot_xx for the subclass and protocol below.
Subclass and protocol codes
| Subclass | Protocol | Meaning |
|---|---|---|
| ff | — | Vendor Specific Subclass |
| ff | ff | Vendor Specific Protocol |
Looking up a specific device instead? Search by VID:PID or browse the vendor directory.