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From: npl@spuxll.UUCP
Newsgroups: net.games.trivia
Subject: Re: Phone Number Taxonomy
Message-ID: <528@spuxll.UUCP>
Date: Sat, 14-Jul-84 18:51:52 EDT
Article-I.D.: spuxll.528
Posted: Sat Jul 14 18:51:52 1984
Date-Received: Mon, 16-Jul-84 05:12:16 EDT
Organization: AT&T Information Systems, South Plainfield NJ
Lines: 19

Having seen some old Telco drawings, etc. for Central Offices,
I can state that, at least in NYC, the exchanges were
originally 2 characters, followed by 4 digits.  (Phone
numbers for the Chief Engr. etc, were listed as
AUdobon 1234, or AU-1234.  The following is conjecture,
but stands to reason that as phone service was getting
to be more and more prevalent, the Telco went from just
a string fo 4 digits to a mnemonic identifying the area of
the city (local countryside) plus four digits.
As more and more people subscribed to phone service, some
exchanges had to grow past 9999 customers.  The fast solution
was to add a seventh digit. e.g. CHelsea became CHelsea-2
and CHelsea-3, -4, -5, etc.

Other than the clue from the old drawings, I have nothing
to back the above other than extrapolation.

			Nick Landsberg