Someone who apparently works in IT at a school or university posted this photo to Reddit this morning and asked: "What is this abomination?"
Wrote the Redditor: "We found it in a faculty office after they left. It's a blue device with an ethernet port... Connected to an ethernet->serial adapter... Connected to a serial->USB adapter. What the hell is this thing?"
Among the early guesses were a motion detector and "some weird type of PoE camera," but an answer remained elusive for about an hour, despite fruitless attempts to help here.
Finally, the fellow who asked found the answer himself: "It's an IR receiver for a classroom voting system. Too bad we don't have remotes for it." Here's more info about it on the website of the Chinese company that made it.
Nice to see the Internet doing its job once again.