Re: Private Line History

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]