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Saturday, March 10, 2012

Confused about 10-digit dialing?

The Triangle will convert to 10-digit dialing at the end of this month. 10-digit dialing is already the norm in much of the USA, but friends seem to ask why it's necessary and whether there were alternatives.

Why is the 919 area code running out of telephone numbers? The two causes are population growth and the advent of mobile phones that assign to a household multiple numbers instead of only one. Even though the 910 and 252 area codes were split away some years ago, 919 is still running out.

Why couldn't the 919 area code be split again? It could, but experience has shown that it's more disruptive to change the area code of so many users. Businesses, especially, don't like that. It also creates ongoing confusion as to where the boundary lies. Go to Atlanta and see what I mean. "Overlays", where two or three area codes are assigned to a given territory, have been found to be less disruptive. Note that even in a split, many calls would still require 10 digits; in some cases, splits have been accompanied by mandatory 10-digit dialing for that reason.

Should we have gone to eight-digit local numbers and kept area codes the way they were in the 1970s? Perhaps. London, Paris, and Tokyo all have eight-digit numbers. In the US, Canada, and the Caribbean, a decision was made 50 years ago that telephone numbers would be fixed at 10 digits. Millions of computer programs and databases were built on that assumption. Changing them would have been costly. Adding an 8th digit in Paris, for example, was not such a big deal because French telephone numbers have always varied in length.

But isn't it a pain to dial a 10-digit number when I simply want to call my neighbor? Yes. People felt the same way in the 1930s and 1940s when telephone numbers went to 5 digits and then 7 digits. Besides, you can't mail your neighbor a letter and just write "City" on the envelope (remember those days?).

How do toll calls fit into this? Even though the price of a long-distance landline call has fallen, regulators still require a 1 prefix on these calls so that people don't inadvertently get billed for a call that they mistakenly think is local. To me it's anachronistic. Mobile phones don't require the leading 1 because you already know that you pay for airtime.

In other words, some landline calls within the 919 area code will still require a leading 1? Yes. That's true for the new 984 area code, too. It depends on whether the called number is within your toll-free dialing area. Again, this matters only for landline phones.

Can one still dial 1xxxxxx to reach a number within the 919 area code that's outside your local calling area? I don't believe so. Most carriers eliminated the 1-plus-7 format years ago to preclude further confusion.

How long will landline phones be around? Indefinitely. Most businesses still use them. On the residential side, landlines are being disconnected at a rate of only 3 to 6% per year.

Can I look at a number and tell whether it's mobile or landline? To a high likelihood, but not 100%. Phone numbers can be "ported" between mobile and landline. There hasn't been a lot of this yet, but over time the exchange numbers will mix so much that mobile and landline numbers become indistinguishable..