Unknown DEC indicator panel

steven at malikoff.com steven at malikoff.com
Tue Nov 1 17:53:09 CDT 2016

> So, the CHM has an RSTS-11 brochure:
>   http://archive.computerhistory.org/resources/text/DEC/pdp-11/Digital.PDP-11.1970.102646128.pdf
> which shows in a couple of places (front cover, page 6, 7, 10, 11) an
> indicator panel which I haven't been able to identify: it's the one where
> there are four full-length light rows on the left, and the lower right row
> of lights is broken up in the three groups - small, large, small. (The other
> indicator panel is known, it's an an RF11).
> I have been searching for these panels for quite a while now, and have a page
> for them:
>   http://ana-3.lcs.mit.edu/~jnc/tech/DECIndicatorPanels.html
> _but_ ... I have never seen that panel.
> I am quite sure that it is _NOT_ an RK11-C panel; although no image of such
> has ever been found (I think because it was never produced - no DEC manual or
> print set refers to it), the RK11-C prints show the wiring for the connector
> to the indicator panel (which would presumably have been a standard DEC 19" x
> 5-1/4" panel of the kind documented on the page above), and from that it's
> possible to predict what it would look like, as shown here:
>   http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/RK11-C_inlay.txt
>   http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/RK11-C_inlay.pdf
> Can anyone shed any light (no pun intended :-) on what this is?
> The RF11 engineering drawings list (on page 187/188) all the inserts
> available (as of that date) for the standard 19" x 5-1/4" indicator panel,
> and I don't have pictures of all of them, so it's possible this is one of
> them. (It's clear from the brochure that this wasn't necessarily a working
> system, since it appears in a number of different configurations. So maybe
> they just grabbed up a random indicator panel and plugged it in to make the
> system look cool.)
> One possibility is that it's a prototype that was never produced - or perhaps
> it was the indicator panel for an earlier RK11 controller (although I can't
> find any mention of an RK11-B or RK11-A, and the list above doesn't contain
> an RK11 entry).
> Anyone have any ideas?
> 	Noel

FWIW the layout pattern also doesn't look anything close to a drum indicator, well
at least not the Foxboro-trim version shown in their doc that used the RC11
controller (M7219 through M7225).

I have been looking but not yet found a picture of the DEC-trimmed RC11 etc. drum
indicator panel to establish how close it is to the Fox one. The 1972 Peripherals
Handbook only shows the drum part of the RC11/RS64 but no indicator panel photo.
If anyone could point me to a photo of the RC11/RS64 DECdisk panel - to be honest
I don't know if it even had one? - I would be grateful. I would know then if the
Fox indicator panel was an own-design or a rebadged DEC item.

I have the RC11 boards and the Foxboro drum interface print set but sadly no
indicator panel nor drum. Foxboro used a DDC 'drum'/fixed-head disk apparently, the
Fox doc shows a different drive unit to the RS64) and also a different indicator
panel to the DDC offering.


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