I've got some old hardware I'm trying to reverse engineer the communications protocol on (it's an old cryogenic magnetometer). It's serial comms between the current control computer and the magnetometer, demagnetizer, and sample handler unit. There are serial to USB dongles connecting each unit to the computer. I'm planning on upgrading all of the control software and the protocol documentation is..... incomplete at best. It's all ASCII characters it appears though. Any opinions on USB protocol analyzers to sniff on this stuff? I want to use hardware as getting a software sniffer on the computer could be problematic. Does anyone have a unit they like? I've been looking at the Beagle 12: https://www.totalphase.com/products/beagle-usb12/
and it seems pretty slick. All of the comms are sub 115200 baud, most 9600.