A rate center is a geographically specific area used to determine the boundaries for local calling, billing and assigning phone numbers. Typically a call within a rate center is local, while a call from one rate center to another is a long-distance call. Rate center boundaries do not necessarily align with county or municipal boundaries.
The rate center is determined by the area code and prefix of a phone number.
Some providers can support certain rate centers and others cannot. Always check with your new provider first to ensure they can support the rate center of your phone number.