The North American Numbering Plan (NANP) governs the assignment and use of telephone numbers within the plan area, which includes the United States and its territories and possessions, Canada, and several Caribbean countries. The NANP is divided into distinct Numbering Plan Areas (NPAs) which are designated by unique area codes. NANP is administered by the North American Numbering Plan Administrator (NANPA), the entity designated by the Federal Communications Commission to administer area codes throughout the United States. Telephone numbers under the NANP consist of ten digits: 1) a three digit area code (also NPA); 2) a three digit central office code (NXX), and: 3) a four digit station number. The supply of assignable NXX codes within an NPA is finite, and with the growth of the telecommunications industry and increasing consumer consumption of phone numbers (traditional copper phone service, Voice Over Internet protocol (VoIP) voice service, and wireless voice service), available supply eventually begins to run out, and the NPA approaches exhaustion. To monitor the NPA supply and demand, NANPA produces NPA exhaust forecasts biannually.
When NANPA determines that a New York State area code could run out of assignable NXX codes within thirty-six months, it files a petition for area code relief with the Commission on behalf of the telephone industry. Commission action is necessary to ensure the continued availability of telephone numbers in the affected NPA. The Commission's goal is to develop a numbering continuity plan that provides long-term area code relief while also minimizing disruption to consumers and businesses in the area.
For areas where the assignable numbers are forecasted to exhaust, the introduction of new area codes in a geographic area are generally provided in two ways: 1) through an “overlay” or; 2) through a “geographic split,” both of which area described below. However, in certain areas, such as New York City, where area code overlays exist from previous NANPA and Commission action, another overlay code is the mandated method for number relief.
21-C-0473 - 516 Area Code Relief Proceeding
21-C-0600 - 845 Area Code Relief Proceeding
In the overlay option, a new area code is superimposed on the existing region with the result that two different area codes serve the same region. Current customers (wireline or wireless) within the region keep the area code and seven digit number assigned to them while new telecommunication services and customers subscribed to those services are assigned the new area code.
Under federal regulations, once an overlay is established, all calls within the existing region will require 10 digit dialing, meaning that the three digit area code plus the seven digit number will always have to be dialed when making a call. For example, anyone calling a number within the new area code, including customers assigned to the new area code, must dial the new area code plus the seven digit number. Similarly, anyone calling a number within the existing area code, including existing customers, must dial the area code plus the seven digit number.
Geographic Split Options
In the geographic split option, the existing area code would be divided into two geographic sections. In one section of the NPA, current and new customers would continue to use telephone numbers with the existing area code. In the remainder of the NPA, all customers, including customers who were previously using the existing area code, would be assigned to and required to use the new area code. However, these customers would retain their seven current digit number – only the area code would change. With a geographic split, customers in either the existing or the new area code would not be required to use 10-digit dialing when making calls within their area code.
The geographic split method divides the region covered by the existing area code into two sections. When the split is made, the boundary between these two sections will follow the boundaries between existing “rate centers.” Rate centers, originally used to determine local calling areas, are useful in this context for providing defined geographic locations for assigned telephone numbers. For this reason, these boundaries may not conform to existing municipal boundaries or physical landmarks.
When a petition for area code relief is received, Department Staff review the petition and identify options for providing additional telephone number resources for the NPA. The DPS will then seek public comment on any proposals made. Interested members of the public can attend information sessions to learn more about the area code relief proposals, and provide their comments regarding the matter at that time, or through the Department’s website at: www.dps.ny.gov
Previous Area Code Relief Proceedings
16-C-0297 - 518 Area Code Relief Proceeding
15-C-0168 - 212/646/917 Area Code Relief Proceeding
14-C-0182 - 631 Area Code Relief Proceeding
09-C-0058 - 347/718/917 Area Code Relief Proceeding
07-C-1486 - 315 Area Code Relief Proceeding