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@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 > > >