Access the NPA NXX directory online after subscribing to a provider of the data, and search for details such as NPA, NXX and Block. Also get information about OCN, Region, Lata and switch including their effective dates.
Some directories have area codes and maps and allow subscription for one year. Only U.S. area codes have effective search dates.
NPA NXX databases provide information about active telephone area codes, exchanges and central office prefixes within the United States, Canada and Caribbean countries. One U.S. area code contains up to 7,919,000 phone numbers, and formats are always NPA-NXX-XXXX. NPA represents the numbering plan area, NXX stands for the central office and XXXX represents the subscriber number. Country abbreviations make up the country details in the directory.
The directory also contains details about county population, ZIP code population, ZIP code frequency, latitude and longitude. Other details available include time zone, overlay, rate center, NXX use type and NXX intro version.
NPA NXX data compilation comes from industry and regulatory sources. The data is used in applications such as call routing and rating, CDR processing and analysis, jurisdictional traffic analysis, TCPA and wireless-do-not-call compliance and caller ID systems. Some directories also provide frequently used numbers and prefixes.