This was made as the input device for a system with a big color CRT. This was a TV tube with new drivers for oscilloscope function. Of course this was not very fast., This device is long gone but this part has survived and is in my workbench, partly because of the attached breadboard.
It is plugged in and I do use to drive circuits on the attached breadboard.
Some signals are connected to columns on the breadboard, as is 5V.
It is line operated.
After much searching I found its schematics in a folder marked ”Dead Projects”.
It seems to date to 1982.