Driver adventures for a 1999 webcam

Wireshark via usbmon under Linux can be used to capture USB traffic. This is especially useful when the device has windows drivers, as usbmon can be used to capture the traffic off a windows VM.

For black box devices, you can build/buy a bus snoop cable and hook that up to usbmon/Wireshark (eg sniff the Xbox Kinect protocol).

Percurnious devices will encrypt/sign their packets to make reverse engineering more difficult, if not impossible, but those are few and far between. You're already buying the hardware and that's the expensive bit, so as long as you've bought the hardware, DRM-style weirdness over USB is rare. Still exists, but most hardware I see these days just uses a generic driver like HID for input, or UVC for video, reducing the amount of snooping needed to make the basics work. Getting extra functionality (like special LEDs) working still requires snooping of the working Windows driver+program though.

I think keyboard emulation was always the way most barcode readers operated.

Amazing, thanks for sharing

And really great write up too!

https://web.dev/porting-libusb-to-webusb/

>I wonder if you could have gotten the webcam to work on Windows 10 by installing the XP driver under compatibility mode.

There are a number of possibilities that might need to be attempted.

In the lab I've got a 20-year old USB HP Laserjet printer plugged into an XP PC which is on my local LAN. Not a network printer but shared with other PCs over the LAN. This was a business printer and the newest drivers were for Windows 7 until the fairly recent Universal Print Driver packages from HP, where the UPD driver supports it with Windows 10/11 when you plug the printer into the USB socket of the W11 PC.

But with the printer plugged directly into the XP PC, then a W11 workstation on the same LAN (with all the permissions right and everything) could still find the printer but not the drivers. You could manually install the printer using the UPD drivers which appeared successful, but it would not print whether you selectied it as default or not.

It was necessary to log in to W11 as an administrator, unzip the old XP drivers, then in File Explorer point to the exact INF file for the exact printer, and right-click for the context menu to Install the INF manually in the background.

No compatibility mode needed, W11 just finds & uses the XP drivers when it connects to the printer after that.

Old Intel USB webcams from 1998 still just plug right in since they were Intel and it's still Windows.

When XP came out it was interesting because a W9x Intel webcam no longer needed drivers and even without any cam app the cam appeared as a device in File Explorer. When you clicked on it in the left-hand panel, the live video appeared in the right-hand panel. Now you need an app but IIRC the built-in modern Windows app may not work. Might have to use Amcap.exe or something more legacy-capable.

Old USB joysticks which were supported in W9x are configured using the same interface as their analog predecessors, and conveniently some modern joysticks can still be configured using the legacy interface (with greatly reduced features) without using the specific hardware driver.