52-pin D-Sub?

[Adam Thornton]

I work at an astronomy facility.  I get to do some fun dumpster diving.

I recently have pulled out of the trash a plugboard with a male and a
female D-Sub 52 connector.  3 rows of pins, 17-18-17.  I took the
connectors off the board: there's nothing back there, so this thing only
ever existed so you could plug the random cable you found into it and its
friends to see what the cable fit.

I can't find much evidence that a 52-pin D-Sub ever existed.

Is this just Yet Another Physics Experiment thing where, hey, if your
instrument already costs three million dollars, what's a couple of grand
for machining custom connectors?  Or was it once a thing?

(also posted to COFF)

Adam