North American Numbering Plan

The North American Numbering Plan (also known as World Area 1) is a system of arranging digits to form a telephone number using a specific pattern of codes. This system was first developed in 1947 to solve certain problems related to the expansion of the telephone network. Some organization was needed and the old system of using named exchanges (e.g. BEnsonhurst 0) wasn't working. The first three digits represent specific regions within North America. The next three indicate the public switched network exchange from which the final four digits representing a specific service subscriber may be found.

1. International Country Codes (World Zones)
2. Area Codes
3. Exchange Codes
4. Local Numbers