To increase the available numbering space ! this restriction was removed in the 1990s ! allowing for any digit (0-9) in the Structure and Assignment second position of an Area Code (e.g. ! 208 ! 303 ! 404). This dramatically expanded the pool of possible Area Codes.
The NANP is administered by the North American Numbering Plan Administrator (NANPA) ! an independent third-party entity under contract to the Federal Communications Commission (FCC) in the United States. Key stakeholders also include the North American lebanon phone number list Numbering Council (NANC) and state-level Public Utilities Commissions (PUCs) or Public Service Commissions (PSCs).
Types of Numbering Plan Areas (NPAs)
Geographic Codes: These are the most common type ! assigned to specific geographic Structure and Assignment regions (e.g. ! 212 for Manhattan ! 310 for West Los Angeles). The goal is to provide enough unique phone numbers within a defined service area.
Non-Geographic Codes: These codes are not tied to a specific physical location but serve special services:
Toll-Free Codes (800 ! 888 ! 877 ! 866 ! 855 ! 844 ! 833): Calls to these numbers are free for the caller and are billed to the recipient.
Premium Rate Codes (900): Calls to these numbers incur special charges to the caller.
Specific Service Codes (e.g. ! 500 for personal communications services ! 521 for certain types of IP-based services).
Assignment Process:
Demand Projection:
Telecommunications carriers project demand for numbers within a specific Area Code.
Exhaustion Forecast: When an Area Code is projected to run out of available technical limitations and issues NXX (Central Office) codes (which each provide 10 !000 numbers) ! the relevant state Public Utilities Commission (PUC) is notified.
Relief Planning: The PUC ! in collaboration with carriers and the NANPA ! develops a “relief plan.” There are two primary types of relief plans:
Area Code Split: The existing geographic area is divided into two or more distinct areas. One portion retains the old Area Code ! and the other (or others) receive a new ! separate Area Code. For example ! when 213 (Southern California) split ! areas received 310 ! 562 ! and others. This czechia businesses directory method often allows for continued 7-digit dialing within each new Area Code boundary but requires 10-digit dialing when calling between the old and new areas.