Probably more than you ever wanted to know about area codes

[unixronin]

From a discussion elsewhere on telephone systems and possible ways to let you dial a logically "nearby" phone using less keystrokes:

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Remember, enough of the phone number space is full that there are essentially no un-issued numbers in existing area codes any more.  ALL "new" phone numbers in existing area codes [with the probable exception of some recently-allocated area codes and some rural area codes] have been previously used, and we've gone from each town having a single exchange and big cities having several, to even smallish towns having multiple exchanges and major metropolitan areas having multiple area codes each, to parts of some major metropolitan areas having overlaid area codes because there aren't enough phone numbers in a single area code and they don't want to split the same area code again.  The pool of available-but-unused area codes itself is rapidly shrinking.

A little research yields:

"The format of an area code is NXX, where N is any digit 2 through 9 and X is any digit 0 through 9.  Initially, the middle digit of an area code had to be "0" or "1". When this restriction was removed in 1995, additional area code combinations became available.  There are 800 possible combinations associated with the NXX format.  Some of these combinations, however, are not available or have been reserved for special purposes."

Among these special purposes, it is noted that 37X and 96X have been "set aside by the INC for unanticipated purposes where it may be important to have a full range of 10 contiguous codes available", and the entire range of N9X has been "reserved for use during the period when the current 10-digit NANP number format undergoes expansion".  Codes with matching final digits (including N11) are reserved for special services.

That leaves 620 usable area codes.  By my best count, 384 of those are currently in use.  33 more have been planned but are not yet in service, for a total of 417 allocated area codes, leaving 203 available area codes for future expansion before they have to increase the number space.  Note that the N[01]X restriction in place up until 1995 limited the area code space to 160, minus the special area codes; subtracting N00 and N11 codes leaves 144 total available area codes prior to 1995.  In other words, in the 12 years since 1995, we have allocated twice as many new area codes as the total number of area codes available in 1995.  If we continue to allocate new area codes at that rate, even assuming a merely linear usage rate, we will exhaust the entire usable ten-digit space by about 2016; and if we make a real-world reasonable assumption about the probable shape of the usage curve, then 2012-2013 is a more likely estimate.

Comments

Re: True, but...

[unixronin.livejournal.com]

Residential customers and a lot of small businesses.

Apart from anything else ... when was the last time you heard of a telco solving any problem in an efficient and cost-effective way...?