DEC MKA11 and/or M8261/M8163

Eric Smith spacewar at
Wed Feb 11 13:55:04 CST 2015

On Sat, Feb 7, 2015 at 7:25 AM, Paul Birkel <pbirkel at> wrote:
> I don't understand the role of the M8162 "Port MUX A module" and M8163
> "Port MUX B module" that the field-guide claims to be part of the MK11.
> They aren't part of the MK11 as far as any documentation that I've read
> regarding it. [...]
> Do these modules really belong to the MKA11, rather than the MK11?

The MKA11 was the multiported version of the MK11, intended for
multiprocessor (11/72 and 11/74) systems. it makes sense that it would
have some "port mux" modules, though I've never seen any documentation
on it.

Reportedly some 11/70 systems were sold to AT&T with the KB11-CM CPU
and MKA11, apparently just as a way to use up the hardware that was
built for the cancelled 11/74.

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