General Question about UNIBUS backplanes

william degnan billdegnan at
Sun May 22 12:09:14 CDT 2016

On Sun, May 22, 2016 at 12:33 PM, tony duell <ard at>

> Strictly the core backplanes are not Unibus backplanes. They have Unibus In
> and Out connectors, but the slots are wired for the core memory board,
> not Unibus boards (like SPCs -- Small Peripheral Controllers -- which is
> what
> you serial port is).
> > Basic Question #1
> > Do I need grant cards in *every* empty slot of the core backplane,
> > including the end slots with the M920's?
> No. In fact in most cases it is wrong to put grant continuity cards in
> there.
> However in a lot of cases a special backplane (like your core memory
> one) will have some spare slots (perhaps the core memory doesn't take
> up all 9 slots). And DEC often (but not always) wired those so you could
> put SPCs in there. In which case you will need grant continuity cards in
> those
> slots if you have nothing else in them.
Are you saying remove all of the GC cards, just leave the slots blank?

Here is a photo of what I have now:

remove the gc cards from the core planes?  I will read up on this more,
just getting started.



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