I'm tidying up in the attic, mainly throwing away defunct computer hardware that I no longer need. I'm tossing most of it into a separate box, which I'll bring along to the next empeg gathering to see if anyone wants any of it, as has happened in the past.

I've come across a cable I can't identify.

It's got a DE-9 connector on one end, and a jack on the other end (but it's not stereo, because it's got 4 contacts, rather than the normal 3). It has no visible part numbers on it.

I think it came with my (long dead) Hauppage PVR350. Can anyone confirm/refute this? What's it for?