But to shut down the dual 3B20 used in switching, you pulled long copper
rod, about 3cm in diameter, from a receptacle between the two machines. It
was attached with a braided conductor to the frame. And then you slid the
rod into another receptacle to short out the power supply for certain.

-rob


On Mon, Nov 28, 2022 at 5:59 AM <arnold@skeeve.com> wrote:

> Georgia Tech got two 3B20s.  They did very little more than consume
> electricity and look impressive.  I wanted to port 4.2BSD to them,
> but that never got off the ground.
>
> "Ron Natalie" <ron@ronnatalie.com> wrote:
>
> >
> > >. But everyone knew what the J stood for. The 3B2 served as a doorstop.
> >
> > Shades of the jerq terminal.    The J prefix persiste in the code long
> > after the nickname was quashed.
> >
> >
> > Being in charge of the Rutgers computer center, we were gifted a lot of
> > ATT hardware.   We had one 3B20 (now that was a pure piece of phone
> > equipment, you shut it down by turning a switch inside and holding the
> > button down until it twanged.   Just like putting an old 303 modem into
> > loop back).   We also got three 3B5's (noted for the one installed in
> > the New Brunswick computing room that got completely drenched when a
> > pipe burst and kept on running) and countless of the 3B2s.    I chortled
> > in that unless you were logged in as root, you couldn't work the power
> > switch.    Yanking the cord out of the wall was still and option.
>