This is a TeleType 5620 Dot Mapped Display (a descendent of the Bell Labs JERQ
or, later the BLIT) served as the main console for SDF from 1994 to 1998. It
runs a windowing system called 'layers' which is a precursor to X windows. It
uses a Western Electric 32000 processor and must download layers from the 3B2
(the second version 8;7;5 TTY5620 actually had layers in ROM).