DEC QBUS Backplanes

Bill Gunshannon bill.gunshannon at
Fri Apr 17 15:37:05 CDT 2020

On 4/17/20 4:05 PM, Glen Slick via cctalk wrote:
> On Fri, Apr 17, 2020 at 9:52 AM Bill Gunshannon via cctalk
> <cctalk at> wrote:
>> I have been sorting thru a bunch of stuff in an effort to
>> clean the place up (Aren't we all doing that now with all
>> this time on our hands?)  I found a backplane.  It says
>> Digital on it but does not  have an H- number.  I also
>> don;t find it listed in any  of the lists I can find on
>> the web.
>> It has 8 A-B slots and 4 C-D slots.  the Four C-D are on
>> the bottom half of the backplane.  I am assuming it is
>> 18 bit and the C-D were intended for things like the 2
>> board RL controller.
>> Anybody familiar with this and able to identify it?
>> Anybody interested in it?  It should fit in a USPS
>> Medium Flat Rate Box.
> Sounds similar to a BA123 backplane which has 4 Q22/CD slots and 8
> Q22/Q22 slots.
> But the BA123 is rather distinctive with a gap then a 13th slot where
> the M9058 Signal Distribution Board for the M7555 RQDX3 is installed.
> For example BA123 backplane part number 54-17507-01 /  50-17506-01

Definitely not that.  Very small.  Just big enough for the
slots I mentioned above.  Power strip on one edge and berg
pins for control on the other.


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