See also here for some better photos of a 5015575-01 board with the DB25
connectors attached:
http://forum.maxiol.com/index.php?showtopic=5196
A DECserver 100 might be the best guess.
On Mon, Jun 18, 2018, 9:49 AM Al Kossow via cctalk <cctalk at classiccmp.org>
wrote:
Is this a 200/DL (RS423 data lines only) board?
https://www.ebay.com/itm/352381870034
A normal 200 would have two large IDC connectors on the pcb for serial I/O