Re: Number length, was Goodbye to copper? [Telecom]

On Jun 30, 7:50 am, Thad Floryan <t...@xxxxxxxxxxxx> wrote:

I can provide one reason: anal-retentive management at some companies. :-)

Real example at one client company in the San Francisco Bay Area: they'd
permit "local" calls from any phone to communities where employees lived,
restrict long distance dialing to those with passwords in the LD file, and
restrict international dialing to those with passwords in the INTL file.

Extension restriction is an ancient function of dial-PBXs. The
simplest, of course, is restricting who can dial outside calls. That
feature is still in use today, such as for hallway phones and the like
that. Years ago employees and visitors who wanted to make personal
calls had to use a pay phone. Most large businesses had payphones for
employee or visitor use scattered throughout the building, such as one
near the restrooms on every floor, several in the cafeteria and of
course in the entrance lobby. (Today, when a large building often
won't have a pay phone at all, it's hard to believe how many payphones
were installed in buildings).

According to the Bell Labs history, in the 1950s they developed a toll
restriction, that is, an extension could dial local calls but not toll
calls. This was done in the central office; apparently certain dial-9
PBX trunks were assigned to that class. The central office of course
maintained up-to-date tables. I worked in a large hospital that had
that service. Most extensions could not dial out at all. Some
extensions (and patient room lines) could dial out locally. In those
days all toll calls went through the PBX switchboard where the
attendant requested time & charges and prepared a toll ticket of the
calling extension.

(I suppose one can still ask for time and charges on an LD today, but
the operator handled-surcharge would far exceed the cost of the call.)

One feature of Centrex was that each extension had its own billing, so
that toll calls were automated billed back to the proper extension,
eliminating the need for the PBX attendant to write up toll tickets.
(Some Centrexes were served by ONI offices.)

Since toll calls are so cheap today many of these features are not
significant today, but they still are in use. Business long distance
still has a charge to it, and certainly international calls do.

.