But making a counterfeit and going to through the trouble to pointlessly connect incompatible signals makes even less sense, doesn't it? Unless the idea is that it should "look legit" by having something on the inside, I guess. But then some 1-cent IC would have made it more believable so it still doesn't quite make sense. Perhaps (perhaps!) I'm now overthinking this. Sorry.
Is there something out there doing the same sort of trick as the mouse? I can't find any reference to one so as far as I can tell these things are entirely useless.
There's a photo of the inside of one which just shows glue and wires, which backs up parent poster's conspiracy theory thinking about companies just making nonsense cables:
There are dozens of these things. All the positive reviews look fake, too.
I can't find any reference to any legitimate product ever that had some sort of passive USB/Firewire adapter.
One review points out that Firewire uses 12V power, and a few others get power warnings from their devices potentially indicating that the pins are just being shorted somewhere.