I have three of these network cards. They came out of an old Novell network. Each card contains a complete Z80 computer (processor, 64K (parity!) RAM, Z8430 Counter Timer Circuit, MC68B54 Advanced Data-link Controller).
Neil Blount mailed me on 2002-09-07, saying
The network card on you page looks very much like a G-Net card, yes it came with a version of Novell and there was a dongle card for the Novell in the Server. It ran a type of ethernet, seem to remember that it worked with other cards. The drivers would be avaliable on Novell's site or on the Novell 2.x disks. Generally I would say they are not worth the trouble to setup but if you really want to :-)
The one card also has a security module of some type, I assume it went in the file server (it looks like a repackaged version of this one).
U3 is a PAL (I'm guessing, but I'd also wager it's (1) registered and (2) read protected), U2 (the one under the epoxy) is a 74S288 ROM.
If you have more info, let me know please...