Could it be a NAS?
Even though it's dead there's a link light on the Ethernet card, can you sniff the OUI?
It honestly looks like someone bought a 1u case and other parts from newegg and threw it together. I'd ask the customer if they have any software in their computers to access it or on their smartphones.
It's not on the network. It's only connected to the cameras. My worry is that it was thrown together and forgotten about plus the end user knows nothing about it. This is sub work for us and we were told to go find out what DVR (they didn't even know it was an IP based system) was installed and quote a replacement. Just thought I'd see what you guys say. I'll probably just quote a new system or pass on the headache.
Definitely looks custom and made of inexpensive parts. The parallel port is a bit of a giveaway. The serial port is also unnecessary if it is a NVR. Crack it open, it seems unlikely there are any warranties to void. If it says a manufacturer on the motherboard that makes consumer motherboards like ASUS, MSI, Foxconn or other I would say it is undoubtedly custom. The lack of identifiers makes it unlikely to be Acti.
Your instinct to quote as new is what I would do.
I probably would edit those photos before posting. The end user doesn't need the phone calls.