North American Numbering Plan
integrated telephone numbering plan serving 20 North American countries which share its resources
There are three-digit area codes and seven-digit telephone numbers.
- "NANPA : North American Numbering Plan Administration – About Us". Archived from the original on 2012-06-04. Retrieved 2012-05-25.
- MEHTA, STEPHANIE N. (1999-02-26). "The Kennedy Space Center Acquires A New Area Code: 3-2-1, as in Blast Off". Wall Street Journal.