[rescue] Creating/Simulating/Emulating an old 1970s Bell Telephone Network

[Paul Mantz]

damn, can I take your class online? :-)

On 8/15/05, Matthew Haas <wedge at lightlink.com> wrote:
> On Mon, 15 Aug 2005, James Fogg wrote:
> >
> > >  I'm wondering if anyone has information or pointers
> > > regarding the above-mentioned topic. I'm teaching a
> > > Data/Voice Communications course this fall, and in my efforts
> > > to convey some deeper understanding of communications (plus
> > > expose these students to things like modems, rotary phones,
> > > even have the opportunity to try out classic coloured box phone
> > > phreaking) I was brainstorming in this area.
> >
> > If you want to duplicate the actual Bell system, you have to span
> > several tiers (long lines, exchanges, etc.) and several generations of
> > electronics (or mechanics in the case of Strowger switches). It would be
> > daunting.
> >
>
>  I'm hoping for a close approximation at this point.. not to necessarily
> have a museum-like replica. Where convenient, some functionality may be
> replaced by ICs and breadboard digital logic solutions (which is why I'm
> looking for a combination of recreation and simulation.. to knock the
> daunting factor down a couple notches... I've got an individual with EE
> experience hooked on the idea too and he's already got his mind humming
> with ideas of implementation).
>
> > >  I'm looking at eventually implementing the CO, switches, and
> > > end devices (be it an off-the-shelf phone, mock-up payphone,
> > > or whatnot).. and to intentionally make it operate on
> > > frequencies, so it can be manipulated...
> >
> > You could acquire an old switch like a Siemens hybrid or a modern AT&T
> > 5ESS with SS7 protocol. But it would be much simpler to find an old PBX
> > or key system that supports type 500/2500 phones (POTS phones). There
> > are many Stromberg-Carlson small exchange switches around too.
> >
>
>  I've got access to a smaller PBX (supports something like 16 phones..
> analog).. And I've stumbled upon the 4ESS or 5ESS, so I'll look into their
> functionality a bit further.
>
>  The idea is to have a system that can handle something in the range of
> 2-8 phones... enough to create some configuration scenarios (like
> exchange dialing) yet hopefully not as mechanically cumbersome. Basically
> the 70s phone network with some benefits of modern technology.
>
> > >  Any recommendations? Web sites, books? I figure this will be
> > > as much a learning experience for me as it will for my students.
> >
> > The web. It's well documented.
> > http://www.att.com/history/
> >
> > You could also build simple phones from carbon mics, simple earpieces
> > and batteries. Add a switchboard for routing, then maybe add a strowger
> > and dials. The facinating thing about the phone system is that the first
> > phones with dials (early 1930's) are still supported. That is why you
> > can dial the operator by pressing the switch-hook 10 times quickly.
> >
>
>  Thanks for the pointers! I'll definitely be exploring the
> phone-from-scratch idea.
>
> -Matthew
>
> ---
>  Matthew Haas
>  Corning/Watkins Glen, NY
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