[kubatyszko]

The Qlogic ISP1040B is a SCSI host chip. So the SCA connector really is just SCSI.
The Intel S82557 is a 100 Mbit Ethernet chip and there is a RJ45 socket.
So the most likely explanation for this card is that it is a NAS server that fits inside a drive bay on a SCA backplane.
There is even a company name silkscreened on the front of the board, although your pictures don't show it clearly. Where it says "XXX, INC. © 1998 ASSY ..."
The pattern of square lands on the circuit board is quite distinctive for equipment fabricated by Digital, and by 1998, Digital had been acquired by Compaq.
But this could also have been a contract for another company, manufactured by Digital.

The company name is "CDS INC".
You certainly have a good theory, but with a single (likely 10/100mbit) Ethernet port, that's unlikely to be an actual data port for said NAS.
It might be some management interface - that would be more plausible.