TELECOM Digest OnLine - Sorted: Re: Private Line History

Re: Private Line History
8 Feb 2007 12:46:51 -0800

On Feb 7, 1:45 pm, Charles Gray <> wrote:

> Beginning probably in the 1960s (before my time there) American
> Airlines (AA) had what was called a "customer controlled switching
> arrangement", or CCSA with AT&T. Of course, they were the only game
> in town in those days. AA eventually had almost 150 locations "on
> net".

Thanks for your post. Interesting stuff.

I think this is the same thing the Bell System history calls "SCAN".

I believe the history is similar to other large organizations. As the
cost of the public message switching network declined, the use of
private tie-lines for voice calls became less attractive. My employer
once had a similar network which was accessed separately, but then it
was removed. All calls to remote locations are placed 9, 1+, but
routed internally over the most advantageous path, transparent to us.

As to the "only game in town", there was also Western Union which had
the legal right to offer private line voice and data services. The
1960s literature states that it offered various kinds of voice private
line service, including a cheaper shared arrangement (e.g. a semi-
switched private line.) How many customers it actually had is tough
to say; I sense not too much. So your statement "the only game in
town" is essentially correct. W.U. wanted to offer such services as
you describe and supposedly had the technology to do so, but
apparently not the customer interest. (Per NYT April 1962). W.U. did
provide many private teleprinter networks in competion to AT&T.

Railroads had their own private networks via lines along their
tracks. The lines of the Southern Pacific Railroad evolved into
Sprint. The gear of the Pennsylvania Railroad / early Amtrak evolved
into my friend's basement (a phone collector).

> In the early 1970s Collins Radio developed the first automatic call
> distributors (ACD) for use outside the phone company. Unknown to most
> people, AT&T had developed their own ACD for internal use, and
> possibly for customer use as well, some time before that. I have a
> Bell System "Traffic Facilities Practice" dated May 1965 in my files.
> Their "service level" objective was 93% in 20 seconds, or an average
> speed of answer in 4-6 seconds.

I'm not sure what you mean by "first automatic call distributor". Do
you mean first not developed by Bell? Bell offered such devices for
many years. They called them "turrets".

The service level is not really dependent on the phone system, but
rather how many attendants are available and how long an attendant
spends on each call.

I think back in those days airlines wanted to give good will and
provided enough attendants to answer calls promptly. These days many
organizations skimp on people. One transit agency had a 15 minute
wait for information. (Not everything is available on line.)

> [TELECOM Digest Editor's Note: Since commercial long distance has
> gotten _so_ inexpensive in recent years, I cannot think of a single
> instance in which a 'private' network would be more economically
> viable these days as an alternative.

One application I can think of is an intercom arrangement.

Data lines still need private connections, it would be impractical to
dial up repeatedly all day long.

When retail stores first card credit card verification terminals, they
were dial up (you could the dialing and connect-up). Of course you
had to wait a moment until that happened before the clerk could swipe
your card. But now it seems those terminals do it immediately, so I
presume they're on some sort of private line service.

I notice many large-chain retail outlets (fast food, gas stations)
have microwave dishes on the roof. I presume this isn't to watch
television, but rather transmit and receive data to/from the central
HQ. I have no idea how these things work, but I would call that a
private line application.

[TELECOM Digest Editor's Note: You note that one application you can
think of is an intercom arrangment. But, Lisa, the telephone network
is a sort of 'giant intercom' is it not? And you say it would be
impractical to have to dial it several times daily. For things like
that, we have speed dialers; you can press a single key and 'dial' a
huge string of digits in a secont or two. A'speed dial' device on your
phone would be substantially less expensive than an entire network,
pwhich in most cases would require 'dialing' anyway. PAT]

Post Followup Article Use your browser's quoting feature to quote article into reply
Go to Next message: Charles Babington: "A Call to Let Your Phone Loose"
Go to Previous message: ellis@no.spam: "Re: Beware of the Dot"
TELECOM Digest: Home Page