USB class 0xef — Miscellaneous Device
Class code 0xef marks a device or interface as Miscellaneous Device. Operating systems read this value from the descriptor and bind a generic class driver, which is why most miscellaneous device hardware works without a vendor driver even when the VID:PID pair is unrecognised.
How it appears on your system
$ lsusb -v
bInterfaceClass 239 Miscellaneous DeviceWindows exposes the same value in the compatible IDs list as USB\Class_EF, extended with &SubClass_xx&Prot_xx for the subclass and protocol below.
Subclass and protocol codes
| Subclass | Protocol | Meaning |
|---|---|---|
| 01 | — | ? |
| 01 | 01 | Microsoft ActiveSync |
| 01 | 02 | Palm Sync |
| 02 | — | ? |
| 02 | 01 | Interface Association |
| 02 | 02 | Wire Adapter Multifunction Peripheral |
| 03 | — | ? |
| 03 | 01 | Cable Based Association |
| 05 | — | USB3 Vision |
Looking up a specific device instead? Search by VID:PID or browse the vendor directory.