Hey Cecil or The Teeming Millions,
They are creating new area codes around the Puget Sound region almost every day because of the increase in fax machines, cell phones, car phones, etc. Why don’t the phone companies just add another digit onto phone numbers so that there are eight numbers instead of seven (e.g. instead of 555-1212 they can use 555-12121)? This would increase the amount of available numbers a factor of 10!! Give me the straight dope!
Patrick
Seattle, WA
Adding a digit to phone numbers also changes the logic that’s in use in phone switches. The switch knows you’re done dialing when it gets the seventh digit. With a change that profound you’d need to switch the whole country over to eight digit numbers.
I think a lot of research went into determining that seven was the maximum digit span that the average person could memorize fairly quickly. In other words, if phone numbers were eight digits long, many of us would forget what our phone numbers are.
A lot of research? I heard that it was decided based on one research paper, namely
Miller, G. A. (1956). ``The magical number seven plus or minus two: Some limits on our capacity for processing information.’’ Psychological Review, 63, 81-96.
Here in Germany, telephone numbers come in various lengths, as do the area codes. For example the area code for Frankfurt is 069 and for Heidelberg it’s 06221. The actual phone numbers themselves are 4-7 digits long; it’s been my experience that the smaller the town, the shorter the telephone numbers, but I don’t know if that is always the way it works.
I have no idea about switches and telephone equipment, or wether it would be feasible to do this in the States.
In Switzerland, phone numbers used to be 5 or 6 digits, but two or three years ago all were changed to seven digits for consistency.
Hong Kong and Taipei each switched from seven to eight digits within the past five years or so, and Tokyo has been that way for years.
DHR
EVERYTHING YOU EVER WANTED TO KNOW ABOUT AREA CODES
It also has a section if you scroll down about WHY NOT 8 DIGIT NUMBERS.
In short, we don’t do it for the same reason Americans don’t drink desalinated sea water or use cars powered by something other than gasoline: it would cost money we would rather spend on consumables and silly stuff. 
My father-in -law works for a not-such-a-baby-anymore bell,
He says part of the problem is that by law exchanges are sold by the 1000. So every exchange gets its own prefix.
So if you only need 10 numbers, 990 go to waste.
According to him, we have used up less than half of our old area code numbers. But they had to split it in half anyway. With another on the way this summer. And the 3rd one will be an “overlay”. So if someone has the 3rd area code they could be anywhere in the original one.
WHAT A PAIN!
Again according to my father-in-law, PA has requested permision to sell smaller blocks of numbers. But the Feds are sitting on their hands. Supposedly some “test areas” have been allowed to break up the prefixes. I have no confirmation on that.
Pained in Pittsburg!
Once upon a time (before my time) there used to be a word plus 5 digits: “Pennsylvania 6-5000”, for example. You’d take the abbreviation for the word and dial the associated numbers.
“I must leave this planet, if only for an hour.” – Antoine de St. Exupéry
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