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<div class="moz-cite-prefix">On 25-May-20 09:29, Bob Supnik wrote:<br>
</div>
<blockquote type="cite"
cite="mid:7534beec-4283-cdf3-bdb0-620cc46d2f62@supnik.org">Looking
through the XVM/MUMPS15 listing, I saw that the timesharing
terminals were attached via a DC01 communications multiplexer.
There's no reference to such a device anywhere in the 18b
literature on Bitsavers.
<br>
<br>
Because the PDP15 is a contemporary of the PDP8/I and the KI10, I
thought it might be a variant of their multiplexers, but I can't
find a match.
<br>
<br>
Another mystery.
<br>
<br>
/Bob
<br>
<br>
</blockquote>
<p>Just for fun, I looked a bit further: <br>
</p>
<p>Here is the DC01-EB system exerciser test (diagnostic) in PDP-15
assembler:</p>
<p><a
href="https://ia800403.us.archive.org/28/items/bitsavers_decpdp15diSystemExerciser19DC01EB_2205397/19_DC01EB.pdf">https://ia800403.us.archive.org/28/items/bitsavers_decpdp15diSystemExerciser19DC01EB_2205397/19_DC01EB.pdf</a></p>
<p>It's rather entertaining reading. Would not like to be in the
room when it runs (on 32 TTYs); it seems to mostly be good for
finding crosstalk. But there's a lot to be gleaned from the code
about how the DC01 works.<br>
</p>
<p>Computerworld 17-Nov-1971 has a classified AD for a PDP-15 with
DC01-EB, MUMPS, and other old friends:<br>
</p>
<p><img src="cid:part2.C140E141.8CBD5DB8@ieee.org" alt=""></p>
<p>Enjoy.<br>
</p>
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