TELECOM Digest OnLine - Sorted: Re: Historical Rules About Private Line Services?

Re: Historical Rules About Private Line Services?
5 Feb 2007 07:34:17 -0800

> [TELECOM Digest Editor's Note: Although what you say is correct, telco
> had very strict rules on things. For example, a pair of wires from
> point A to point B which did not go near an 'actual phone line' but
> was still used for communication purposes was regulated according to
> Bell rules and defined as a 'private line' according to their
> rules.

Many large organizations, such as a transit system, city government,
or large manufacturing plant, had their own private telephone
networks. As I understand it, these networks were not interconnected
with Bell and operated and maintained by the owner. In the 1960s and
even 1970s you would see two phones on a desk, a typical Bell 500 set,
and then an obviously old AE (Automatic Electric) phone, with a fabric
cord, the metalic stripe accents on the handset, etc. I doubt that
the owners of such systems paid Bell anything for them, otherwise,
they would've interconnected and been more up to date.

I recall an old Bell Telephone employee magazine showing a picture of
such a desk with the caption: "This is lost revenue! We [Bell
employees] need to encourage businesses to switch from their private
networks to our service."

I think in the old days the cost of a large private system, especially
when the organization was big enough to have maintainers already on
staff, was cheaper than Bell. Bell Telephone service was relatively
expensive before WW II.

The Phila public schools had a modest PAX (private automatic exchange)
in most schools for internal use within the school. Each classroom
had a non-dial phone. When the handset lifted it rang in the school
office. The school office phone had a dial. No interconnection to
Bell. I suspect such a system required only one SxS switch and a few
relays. I understand that system is now gone and now classroom phones
have dials, and parents can call a teacher directly, instead of making
the teacher come to the school office where the outside line was.
(I'd love to know what happened to that gear when replaced.)

If anyone can offer more about such large private networks used in
industry, I would appreciate if you'd post it.

In the 1980s the age of the wire plant and switchgear caught up and
doomed such old systems. Also, Bell had more attractive rates for
distributed Centrex.

[TELECOM Digest Editor's Note: I know that through the 1950-1970 era,
Chicago Police had a PAX network (with old, AE type dial phones)
everywhere, but a limited number of Bell phones and extensions wired
through the old WABash-2-4700 switchboard in their headquarters. Then
around 1965 or so, Chicago police were cut into the 312-PIG centrex
system out of City Hall. Around 1970, all the old Automatic Electric
phones and the PAX thing were totally gone. Then about 1995 the old
312-PIG network was replaced with most city offices staying on 312-744
but police going onto 312-745 I think, and a few other departments
going onto 312-746. The system now for City of Chicago internally is
dial last five digits (4,5,6) plus the final four digits. PAT]

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