Another mystery prototype on ebay.....

[LoadWB]

The profile of the chip looks like RAM, but check this out:

COM20020P
Category:   Communication => Network => ArcNet/CAN
Description:   Ulanc Universal Local Area Network Controller With 2k X 8 On-board RAM
Company:   Standard Microsystems Corporation

Edit: DigiChip has the datasheet for the SMC chip.

This may be newer than the A560 ArcNet controller, but I would hazard to wager that it may have been an update to the A560.  BBoAH says the A560 has a SANA-II driver and, "AS255r TCP/IP stack has built-in support," as does the A2060.

Now, this has mini-DIN and two RCA jacks, which appear much different than the coax/BNC connectors I have seen referenced for ArcNet.  I did not get involved with networking (other than the huge token ring stuff on the System/34) until after Ethernet had been well established so I cannot make any historical reference from experience.

[LoadWB]

Well, think about video cables:  RCA and coax are adaptable to each other with minimal difficulty.  Maybe in this prototype version they just stuck with RCA jacks for ease of implementation and testing.  (and size.)  f.ex, the cables used by S/PDIF audio are actually just video cables, same as what you hook up to your TV, or to the Toaster but with RCA ends on them instead of BNC.  So maybe instead of heavy-duty cables with BNC connectors, they were able to use cheap and readily available composite video cables and RCA jacks for testing.  Sorry for poor wording, it's early and this is all just hypothetical.

I would concur.  I run S/PDIF from my laptop docking station to my receiver using an inexpensive video cable; works great.  From a prototype perspective, RCA connectors and cabling would be much less expensive than BNC and coax (for the time period, at least) so it makes sense.

Now, two of them, and what is the mini-DIN? hrmmmmmm (need a rubbing chin emoticon here)  Anyway, I'm off to pretend to work today.