We've got these rack mounted video transmission units in a server/equipment room, and they're labeled "The Fox dBm Digital Broadband Multiplexer", but I cannot find a single relevant Google result for this product.
As far as I can tell, they convert analog video to some digital format for transmission over fiber optic lines, then back to analog at the receiving end. They were installed c. 2001.
Any information would be helpful, because we've got a few cameras that are having degraded quality and we need to start troubleshooting.
Here's what they look like:
