Paul Birkel pbirkel at
Sun Jul 1 08:14:19 CDT 2018

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Noel
Chiappa via cctalk
Sent: Sunday, July 01, 2018 8:12 AM
To: cctalk at
Cc: jnc at
Subject: Re: DEC FPJ11-AA

    > From: Paul Birkel

    > Same thing in this case. 

The CPU looks to see a PMI signal that is generated by the KTJ11 - no signal
-> 11/83.

My impression is that except for the speed of the J11 (and the crystal), and
whether or not it came with the FPJ11, all four of the M8190 board variants
are otherwise identical. Whether it's a /73, /83 or /84 depends entirely on
whether it has/sees PMI memory and the KTJ11-B UNIBUS converter (and the
correct backplane, for the latter, of course).

    > The 11/84 is an 11/83 extended by a Unibus interface to support legacy
    > peripherals.

It has a special backplane which is mostly UNIBUS slots, with a few QBUS/PMI
slots on the front, and a 'special' slot in the middle into which the UNIBUS
adapter goes.


Indeed.  As you say WRT the question asked, "same difference" excepting the
Xtal/speed rating.  The backplanes, power supplies, enclosures are of course
radically different as they serve different commercial objectives.  And as
you say, the -AE ought to work in either environment.


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