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Rate Centers

The North American Numbering Plan (NANP) is divided into over 27,000 "rate centers", which are arbirtary geographic areas used to logically segment TNs into regions that determine a subscriber's local calling area.

While the association between a TN and its geographic area is much less important in today's age of mobile phones and flat rate calling plans, the rate center is often still significant:

  • Many mobile phones will display the city & state of the caller TN's rate center when receiving an inbound call from an unknown number.
  • TNs can only be ported betwen two carriers that support a given rate center
  • Landline carriers, especially ILECs, will often refuse to activate service at a physical location unless the desired TN's rate center matches that location. While this restriction can easily be overcome by using a call forwarding plan, it is a customer service hazard nonetheless.
  • Smaller communities (typically ones that have a single "exchange", or NPA-NXX) may still have an affinity towards numbers within their rate center.

All else being equal, it often makes sense to guide users towards choosing telephone numbers that are within the rate center that corresponds to their physical location. The Available Telephone Numbers API can return TNs whose rate centers are close to a particular point (coordinate, IP address, or postal code)

== Toll Free ==

== Computing the nominal distance between rate centers ==

Rate centers are assigned a "nominal location" which is an arbitrary point from which calling distance is measured for billing purposes. Historically, this has been the location of the incumbent carrier's (ILEC's) "wire center", which is where the community's copper wires .......

In some regions, "local calling areas" (LCAs) prescribe free calling between rate centers within a certain number of miles. This is a regulatory construct and generally is not related to geographic distance.

To compute the "billable distance" for a call between two TNs, you must take the...

Common uses for this API are to determine the rate centers in a given state or LATA:

GET /api/rateCenters?state=KY
GET /api/rateCenters?lata=832

Or to find rate centers that are near a particular point:

GET /api/rateCenters?$near=33.1084851,-117.0935871
GET /api/rateCenters?$near=92025
GET /api/rateCenters?$near=V8W+3M9
GET /api/rateCenters?$near=64.130.190.160

Or to compute the nominal distance between rate centers, often used for billing purposes:

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We pull this data from a variety of sources in the public record, including:

  • North American Numbering Plan Administrator (NANPA)
  • Canadian Numbering Administrator (CNAC)
  • FCC Electronic Tariff Filing System (ETFS)

While we make every effort to keep this data accurate and up-to-date, your mileage may vary. Please contact api-support@numberbarn.com with any comments, concerns, or corrections.