PDP-11/44 mystery card

Pontus Pihlgren pontus at Update.UU.SE
Thu Aug 5 15:06:13 CDT 2010

> Hi Pontus,
> congrats on this acquisition.

Thank you!

> I had a quick look at the list.
> When looking at Expansionslåda 2 (lös) I frowned seeing the 11/24
> CPU module there. Now, I don't now if you wrote them down in the
> order the modules are in the slots (like the first 11/44 CPU), but I
> think you better check all positions before applying power!
> Now, my Swedish is nill, but I think "lös" means something like
> "loose" , "just a bunch of modules" put together in the expansion
> box, where the expansion box functions as a storage drawer.
> I use BA11-K boxes too as storage boxes ... never apply power!

You are right, lös is loose, the box doesn't even have a power supply. I 
was to surprised to find a 11/24 there. The box has a card listing from 
an 11/24 on it, but the rest of the cards probably come from the 11/44.

> >There is two cards connected with ribbon cables that I can't identify.
> Sorry, can't be of much help here.
> >Also I wonder what the
> >"M7251   KG11-A      U   Network interface XOR and CRC block check option"
> >"M3110   DRCSA       U   Protocol assist #1 w/special character
> >check and CRC (DEC/DLC/DRCSA)"
> >"M3111   DRCSA       U   Protocol assist #2 w/special character
> >check and CRC (DEC/DLC/DRCSA)"
> >are used for?
> AFAIK, the KG11-A "belongs" to serial comm cards and adds
> error checking on the data stream. My guess is that the M3110/3111 are
> modules that "seek" for a special character and generate a CRC for
> error checking purposes ... just a guess.

I see, thank you.


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