TELECOM Digest OnLine - Sorted: Re: Question About NXX Exchange Numbers: Are They Geographic

Re: Question About NXX Exchange Numbers: Are They Geographic

Michael D. Sullivan (userid@camsul.example.invalid)
Thu, 10 May 2007 07:29:28 GMT

On 5/7/2007 5:23 PM, Patrick E. Burns wrote:

> I work for a non-profit which is just about to conduct a telephone
> survey of rental households in Los Angeles, and we are seeking maps
> (or mapable information) about telephone numbers. When we call renters
> (as well as smaller sample of apartment owners), we want to know if
> they fall in the City of Los Angeles or an adjacent community.

> My understanding is that telephone exchange numbers can represent
> geographic areas, similar to a ZIP code area or census tract. Is
> that the case?

As others have pointed out, NXX codes or exchange numbers are
associated with a rate center, which has geographic coordinates.
Others have also pointed out the possible effects of number
portability, especially landline-to-wireless, which would have the
effect of not ensuring any copper-wire-based geographic association
between the number and the area, and there are issues as well about
how often people move to a different area after porting their number,
and how many people actually port landline to wireless.

I would like to point out a different and probably more important
issue regarding non-correspondence between the rate center location
and the actual location of the user. That is that an increasing
proportion of people -- especially the young, which may be significant
as your are talking about renters -- use only wireless phones, with no
landline. Wireless carriers, unlike landline carriers, do not take
numbers in every rate center they cover with radio signal; nor do they
require the customer to take a phone number that is associated in any
way with the area where the user lives or is billed.

While I have landlines phone numbers at our Maryland home in the
301-320-xxxx range, my wife and I both have cellphones with the
Washington, DC 202-365 prefix. My son and daughter both have
cellphones with the 301-467 prefix, which may or may not be associated
with our landline rate center. Moreover, my daughter spends 9 months
of the year at college in Florida; she exclusively uses her Maryland
cellphone number, and that number may not even point to our area of
Maryland; it certainly does not identify her general location in

Renters tend to be younger than homeowners, so they are more likely to
cut the cord; also they tend to move more often, and I would expect
them to keep their wireless number when they move and very possibly
use only that number. Accordingly, I would not be surprised if a
significant proportion of the telephone numbers of L.A. renters are
wireless numbers, which may well be associated with any of the many
rate centers in the City of L.A., Los Angeles County, and surrounding
counties, and a significant proportion will be wireless numbers from
other areas entirely. When people cut the cord, they will upset your
expectations. They will keep the same number whether they are living
in the City of L.A., Venice, Century City, Pasadena, or even San
Diego; and they may well have a phone number that is supposed to be
from San Francisco, N.Y., or somewhere else.

Michael D. Sullivan
Bethesda, MD (USA)
(To reply, change example.invalid to com in the address.)

[TELECOM Digest Editor's Note: This is also true with the increasingly
large number of VOIP phones on the market. Vonage even encourages
folks to take numbers in 'any area code desired'; after all, the
service is unlimited for $24.99 per month. PAT]

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