Perhaps it's some sort of old school wireless access point? Does it have any place to plug power into it?
Some of the older networking stuff had an RJ-45 (cat-5) jack, an AUI connector, which looked like a slightly shorter DB-25 (printer) port, though I can't recall how many pins off the top of my head, and a BNC jack for coax.
If it were me, I'd bust out a screwdriver and see what the guts look like
