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Message-ID: <8704290548.21717@ur-seneca.arpa>
Date: Wed, 29-Apr-87 01:48:07 EDT
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Posted: Wed Apr 29 01:48:07 1987
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By making the middle digit of the area code a 1 or 0, the phone
company could tell if you were dialing long distance or not.

Now I am starting to see exchanges with 1 and 0 in them, and
ones without an alphabetic mnemonic, as the number of 
available prefixes is getting used up.

Mike Ciaraldi
seismo!rochester!ciaraldi

Path: moscom!ritcv!rochester!ciaraldi
From: ciaraldi@rochester.ARPA (Mike Ciaraldi)
Newsgroups: comp.dcom.telecom
Subject: Re: ring ship; area code history
Message-ID: <27353@rochester.ARPA>
Date: 28 Apr 87 02:32:23 GMT
References: <8704242209.AA11757@jade.berkeley.edu>
Reply-To: ciaraldi@rochester.UUCP (Mike Ciaraldi)
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Organization: U of Rochester, CS Dept, Rochester, NY
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In article <8704242209.AA11757@jade.berkeley.edu> SPGDCM@CMSA.BERKELEY.EDU writes:
>
>
> From:    Doug Mosher                 <SPGDCM at UCBCMSA>
> Title:   MVS/Tandem Systems Manager  (415)642-5823
> Office:  Evans 257, Univ. of California, Berkeley, CA 94720
> Subject: ring ship; area code history
>
> Roger Orr of
> Pacific Bell was able to answer... Area codes were invented in 1946, he said,
> and the first thing determined were the middle digits. States containing more
> than one area code, such as New York and California, were assigned a 1 in the
> middle. States that had only one area code at the time (today, they may have
> more), were assigned... 0 in the middle. Thus, California had 213 (Los
> angeles), 415 (Bay Area) and 916 (Sacramento area). Vermont was 802.

But why a 1 or 0 in the middle digit?
About 15 years ago I was visiting New York City for the first
time, and tried to make a long distance call.  It took quite a while
to realize that I didn't have to dial "1" first, unlike Rochester.
(no longer true, now NYC people have to dial 1).

At the time I wondered how the phone company could tell that the
first 3 digits dialed were an area code, rather than an exchange.
Then I realized that exchanges were traditionally based on words,
e.g. my home exchange was "Hopkins 7".  You could dial either
HOP or 467 and it would be the same, since H = 4, O = 6, and
P = 7.  Because 1 and 0 do not have letters on the dial,
it was impossible to have a 1 or 0 in an exchange.
By making the middle digit of the area code a 1 or 0, the phone
company could tell if you were dialing long distance or not.

Now I am starting to see exchanges with 1 and 0 in them, and
ones without an alphabetic mnemonic, as the number of 
available prefixes is getting used up.

Mike Ciaraldi
seismo!rochester!ciaraldi