Area code 403
Area code 403 is a telephone area code in the North American Numbering Plan (NANP) for the Canadian province of Alberta. The numbering plan area encompasses the southern third of the province, which includes the Calgary area. Area code 403 was one of the original eighty-six area codes assigned by AT&T in 1947. Its numbering plan area (NPA) originally comprised the entire province of Alberta, the Yukon, and the western half of the Northwest Territories. It was the second-largest numbering plan area in the North American Numbering Plan and spanned more than one ninth of  the circumference of the planet, from the 49th parallel north to the North Pole. On October 3, 1997, the numbering plan area was reduced to Alberta, and the Canadian territories were split off with the new area code 867. Within only a year, area code 403 was threatened by exhaustion because of the rapid growth of telecommunication services demand for pagers, cellphones, and computer modems, as well as growing competition among providers. Every local exchange carrier is allocated entire blocks of 10,000 numbers that correspond to a single three-digit central office prefix for every rate centre where they plan  to offer service, even for the smallest hamlets. Most rate centres do not need nearly that many numbers, but numbers cannot be moved from one rate centre to another. That resulted in many unused numbers. On January 25, 1999, the northern two thirds of Alberta, including Edmonton, was split from 403 and assigned the new area code 780. Generally, everything from Red Deer, Lacombe, and Ponoka southward stayed in 403. Permissive dialing of 403 continued across the province until May 18, 1999. That was intended as a long-term solution, but within a decade, area code 403 was close  to exhaustion once again. To solve the problem, a decision was made to implement area code 587 as a province-wide overlay. Optional provincewide 10-digit dialing began on June 23, 2008 and became mandatory on September 12, 2008. On September 20, 2008, Telus Mobility began to assign 587 numbers to new customers in Calgary and Edmonton. The incumbent local exchange carrier (LEC) in 403 is Telus. Prior to 1997, the larger 403 included EdTel (Edmonton Telephones, now part of Telus) and Northwestel as incumbent LECs. Prior to 1990, Telus was known as Alberta Government Telephones and was a department  of the provincial government. Relief Planning. The projected exhaust date for Area Code 403 was March 2009. For more information see the Canadian Numbering Administrator Website. Two area codes, 587 and 825, have been reserved and the first one, 587, was introduced in September 2008. The 403 area code, simultaneously with area code 780, will be overlaid with the new area code, which will cover the entire province.