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Telephone line numbers, prefixes, and area codes
Nobody wrote:
"Adam H. Kerman" wrote: Nobody wrote: It intrigues me as to why North America cannot go to area code + eight-digit addressing. Theoretically, you're increasing the number availability by ten but don't have to create a new area code. Aussie's done it, so have Brazil, Japan, France... If planned for early enough, it could have been done if use of 0 or 1 as the second digit was for longer line numbers. But you're misunderstanding the situation that leads to the opening of new area codes, which is not now, and never has been, about rapid exhaustion of line numbers. I'm not misunderstanding anything! I know why these area codes are required. All I'm saying is for simplicity's sake for the Average Jo and Joe, one area code for local calling would be easier than a bunch of disparates. It would have been lovely if we'd stuck with most of the geography of area codes as it existed by the late 1950's. But if we're doing things completely differently, why must all telephone number be the same length? Do you know how ISBNs work? They can be purchased by publishers in blocks of 1, 10, 100, 10000, or 100000. Every element of the code varies in length based on how many different publishers or imprints were expected to exist in a particular country. Then the publisher or imprint decides for itself how many numbers to buy. Anticipate lots of publishers? 1 digit country or group code. A publisher anticipates lots of titles? Assign a shorter registrant element to the publisher. Each ISBN consists of 5 parts with each section being separated by spaces or hyphens. Three of the five elements may be of varying length: Prefix element -- currently this can only be either 978 or 979 (it is always 3 digits). Registration group element -- this identifies the particular country, geographical region, or language area participating in the ISBN system. This element may be between 1 and 5 digits in length. Registrant element -- this identifies the particular publisher or imprint. This may be up to 7 digits in length. Publication element -- this identifies the particular edition and format of a specific title. This may be up to 6 digits in length Check digit -- this is always the final single digit that mathematically validates the rest of the number. It is calculated using a Modulus 10 system with alternate weights of 1 and 3. Note that as the publishing industry was much more advanced about item numbering than other manufacturers of retail goods, and had so many different titles, the EAN (International Article Number) was designed around these codes, and to avoid numbering book titles in EAN numbering space, which would have overwhelmed the system. Instead, an artificial country called Bookland was created, with number 978. At first, 978 was prepended to ISBN to form the EAN, with the check digit recalculated. Later, ISBN-10 became ISBN-13 making it the same code as EAN. In 2005 and 2006, both ISBN-10 and -13 were shown on books. Starting in 2007, only ISBN-13. As 978 exhausts, 979 will be used, but the United States and other groups/countries will continue to have sufficient code assignment space. Suppose we'd used a system like this for telephone numbers. Then exchanges serving areas with lower populations could have issued shorter line numbers. If the overall number length was to be the same a la ISBN, then the small exchange codes themselves could have been longer. A state with few exchanges might have been assigned longer area codes. A country with a larger population would have been assigned a shorter country code. "If planned early enuf"? Oz, France, Brazil, Japan I doubt would've been planning any further ahead so it cannot be that difficult to achieve. I'm sure there was five to ten years advance planning. There is a lot of equipment to convert, given that telephone switches have 40 year life spans, not to mention a lot of reprogramming in the private sector. This is exceedingly costly. It would however stop this "overlay" situation, e.g. here in Metro Vancouver where 778 is overlaid on 604 and a third (236) has been assigned for use beginning next year. Oh, don't complain to me about overlays. My area started out with two area codes. The smaller one got an overlay in 2007. The larger one was split. One split was split again, then overlayed. The other split had two codes split out, with overlays now in effect for two of the three. We went from 2 to 10. You want to avoid new area codes? Then force each phone company to assign line numbers from a common pool. Use an independent lookup like LNP to route calls to the correct network and don't rely on area code+prefix for routing. |
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