Area Code Day

Area codes were created fin the labs of AT&T and Bell in 1940. The concept of using area codes grew and modified with time. In 1947, area codes helped to overcome the shortage of phone numbers in countries like the U.S. and Canada through the North American Numbering Plan (NANP).

The first area code was rolled out in 1951 to New Jersey. The 201 area code was born. Because this was still the time of rotary dial phones, the areas with the biggest populations received the easiest to dial codes. New York received 212, Los Angeles got 213, and Chicago became 312.

The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the international calling code 1. Some North American countries, most notably Mexico, do not participate in the NANP.

The NANP divides the territories of its members into numbering plan areas (NPAs) which are encoded numerically with a three-digit telephone number prefix, commonly called the area code. Each telephone is assigned a seven-digit telephone number unique only within its respective numbering plan area.