The crew over at the Hungarian Autonomous Center for Knowledge (H.A.C.K.) say they aren’t the most well-funded organization out there, so they were stoked when they found they could afford to bring a slightly used UNI-T UT2025B digital oscilloscope into the shop. As they started to tinker with it, the scope revealed one major shortcoming – screenshots were only accessible via a USB connection to a Windows computer.
Since they didn’t have any Windows boxes in house, [András Veres-Szentkirályi] decided he would try reverse-engineering the protocol so they could get access to this useful feature.
He set up a Windows VM, and using Wireshark on the host Linux box, [András] sniffed the data passing over the scope’s USB interface. He was able to identify what looked like image packets being sent to the VM, which he was able to decode using a small Python script. The resultant images were monochrome and they didn’t look quite right, but it was a start. As he dug further [András] found that he was overlooking some of the color data packed into the images, and after a bit of fiddling he got the sharp, colorful image you see above.
It turns out that while the scope has a monochrome LCD, it sends 16-bit color images over the USB interface – images that the Windows’ client degrades before displaying them on the screen. So in the end, he was not only able to get the scope working on any OS with the ability to run Python, he was able to grab far better images than the manufacturer ever intended – A very nice hack if we do say so.