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Because of wireless phones, pagers, the Internet and other telecommunications services that became popular in the 1990s, consumers throughout the United States and Canada have needed additional phone numbers at an increasing rate. The shrinking of phone numbers available for distribution is called “number depletion.”
To create new telephone numbers to keep up with demand, new area codes have been introduced in 37 states, including Indiana, in the last two decades. In fact, the number of area codes in the United States has more than doubled since 1995. While the need for new numbers has continued in recent years, the pace has slowed dramatically due to number conservation efforts that make more efficient use of existing numbers and have delayed the need to implement many new area codes.
The most significant number conservation effort is "1,000 block number pooling," which Indiana started using in 2001. Traditionally, telecommunications providers were allocated blocks of 10,000 numbers, which often left numbers unused. Now, numbers can be allocated in blocks of only 1,000. The use of 1,000 block number pooling has significantly delayed the need for new area codes in most of Indiana.
When North America’s telephone numbering system went into effect in 1947, three area codes were assigned to Indiana: 219, 317 and 812. These codes remained largely unchanged for nearly 50 years, until number depletion became an issue.
The 765 area code was introduced in 1996, as a split from the 317 area that spanned the central third of Indiana. Communities outside the Indianapolis metropolitan area that had used 317 were assigned the new 765 area code. Indianapolis and most of its suburbs continue to use 317.
In 2002, the 219 area that had spanned northern Indiana for decades was divided into thirds, with the new 260 and 574 area codes being introduced.
Had 1,000 block number pooling not been implemented, other parts of Indiana would have required additional new area codes in recent years. While relief measures are delaying that need, each area code has a finite supply of available numbers – meaning that future changes are inevitable.
Among Indiana’s original three area codes, only 812 – spanning the state’s southern third – has not required major changes. However, the current industry forecast* projects that 812 will run out of numbers in the second quarter of 2015. Forecasts several years ago set 2004 as 812’s expected exhaust date, but number conservation efforts have extended the lifespan considerably.
1,000 block number pooling has extended the 765 area code’s projected exhaust date to 2027 – a 23-year extension beyond projections made a few years ago.
The 317 area code’s number supply is currently projected to run out in 2016 – 14 years later than projections made before 1,000 block number pooling was implemented.
The three area codes serving northern Indiana (219, 574 and 260) are expected to need no additional changes before 2032.
After efficiency efforts are exhausted, new area codes can be implemented either by geographic split or overlay.
In a geographic split, an existing area code zone is split into at least two parts. One part typically keeps the original area code while the other part(s) is assigned a new area code. A geographic split does not change the boundaries of a consumer’s free local calling area. Most local calls are still placed using seven-digit dialing.
In an overlay, a new area code "overlays" the entire geographic area covered by the existing area code. Existing phone numbers, fax machines, etc., retain current area codes and phone numbers, but new phones and telecommunications devices may be assigned numbers using the new area code. An overlay does not change the boundaries of a consumer’s free local calling area, but all calls - including free local calls - usually require 10-digit dialing.
* Projections in this fact sheet are according to North American Numbering Plan Administration (NANPA) data released in April 2012. NANPA is the neutral, third party administrator that oversees area code assignments. For additional information on area code relief, as well as state maps of area codes in North America, visit NANPA’s Website at http://www.nanpa.com/.