52-pin D-Sub?

[Paul Koning]

> On Feb 27, 2020, at 6:37 PM, Adam Thornton via cctalk <cctalk at classiccmp.org> wrote:
> 
> 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?

No idea.  I just got a new L-Com catalog, which has a large section of "D-Sub" connectors and cables.  It lists the following sizes:

2-row: 9, 15, 25, 37, 50 pin
3-row: 15, 26, 44, 62, 78 pin

So 52 pins is halfway between two standard sizes.  For some definition of "standard", of course.  2-row 9, 15, and 25 pin are common, 37 is for RS-422 if I remember right but I haven't seen it in ages.  The only familiar "high density" (3-row) connector is the 15 pin one for VGA.

Those connectors correspond to the standard D-sub shells DE, DA, DB, DC, and DD in that order -- as many people here know, the common 9-pin serial connector is not actually a "DB-9" connector but rather a DE-9.  

Is the connector a DC shell with pin spacing increased from the standard 62 pin pitch?  Or is it a DC-62 with some positions left unused?  A picture would be interesting.

	paul