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<p>Hello,</p>
<p>You beat me to it! I was about to reply that the Connections
Museum of Seattle would have more info about this, or know people
who do.<br>
</p>
<p>This video of their channel shows a 3ESS software boot :
<a class="moz-txt-link-freetext" href="https://www.youtube.com/watch?v=k865-VjWUk8">https://www.youtube.com/watch?v=k865-VjWUk8</a><br>
</p>
<p>Sebastien<br>
</p>
<div class="moz-cite-prefix">Le 26/09/2023 à 04:20, Kevin Bowling a
écrit :<br>
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cite="mid:CAK7dMtCFj-TqP_FnEg5LmASiiCm_hm6PwoMxZBquUV1kBWnR4w@mail.gmail.com">
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<div dir="ltr" class="gmail_attr">On Mon, Sep 25, 2023 at
6:25 PM segaloco via TUHS <<a
href="mailto:tuhs@tuhs.org" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">tuhs@tuhs.org</a>>
wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Hello, my studies
lately bring me to the question: Are there any extant
examples of telephone switching software, built on UNIX,
from the various parts of the Bell System prior to the
introduction of the 5ESS and 3B20D? My focus veers
earlier as some 5ESS/3B20D/DMERT technology is still in
active use, that sleeping dragon can lie.<br>
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<div>Your best bet may be to contact Sarah Autumn at the
Connections Museum, they have a 1ESS and 3ESS.<br>
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<div><a
href="http://www.telcomhistory.org/connections-museum-seattle-exhibits/electronic-switching/"
moz-do-not-send="true" class="moz-txt-link-freetext">http://www.telcomhistory.org/connections-museum-seattle-exhibits/electronic-switching/</a></div>
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<div>I don't remember if they have the 1A variant but they
should have the BSPs for all of this which would give you
a lot of what you are after.<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
What's gotten me curious is reading about 1ESS in a BSTJ
volume I picked up, noting the particulars on how previous
concerns of manual and electro-mechanical systems were
abstracted into software. Even without surviving
examples, were previous systems such as the 1ESS central
control ever ported to or considered for porting to UNIX,
or was the hardware interface to the telco lines too
specific to consider a future swap-out with, say, a PDP11
running arbitrary software? Columbus's SCCS (switching,
not source code) also comes to mind, although all I know
that survives of that is the CB-UNIX 2.3 manual
descriptions of bits and pieces.<br>
<br>
By the way, it's funny, I have UNIX to thank for my
current experiments with telephones and other signalling
stuff, what with making me study the Bell System more
generally. It's starting to come full circle in that I
want to take a crack at reading dialing, at least pulse,
into some sort of software abstraction on a SBC that can,
among other things, provide a switching service on top of
a UNIX-like kernel. I don't know what I'd do with such a
thing other than assign work conference call rooms their
own phone numbers to dial with a telephone on a serial
line...but if I can even get that far I'd call it a
success. One less dependency on the mobile...<br>
<br>
- Matt G.<br>
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