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To: dalereed
Totally stupid, they should make all numbers 8 digits and they increase all of them by 10 million.

You need to spend some time in some competent telecom books. Pay attention to the development of the switching network and dialing plans. The choice of 7 digit number was made because that's the ideal number for humans to remember. Early in the life of the network, the second digit of the 3 digit prefix disallowed the use of digits 0 and 1. That is how the area codes were discerned. The needs for additional numbers and the advent of electronic switching allowed the use of 0 or 1 in the second digit. That expanded the available phone numbers in an area code, but required dialing a country code first. The country code for the United States is conveniently "1".

Area code splits are a hell of a lot of work. I've worked a bunch of them during the years at PacBell. Doing an overlay is comparatively simple.

I remember when they did it in Los Angeles from 6 to 7 digits to increase the numbers.

You're old enough to remember that point in time. The original switching machines were designed for numbers in the range of 0000->9999. The digits above that were used to select the outgoing trunks to another switching office. The "magic" 3 digit area code with 1 or 0 as the second digit did the long distance mapping from area code to area code. The next 3 digits did the end office selection. The last 4 digits mapped to a customer line.

44 posted on 07/23/2006 6:16:36 PM PDT by Myrddin
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To: Myrddin

" The choice of 7 digit number was made because that's the ideal number for humans to remember."

Those people shouldn't have telephones.

I probably know 20 phone #s that I use, my SS#, bank account #s, etc. and never write any of them down.


50 posted on 07/23/2006 6:37:07 PM PDT by dalereed
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