Rate Center Coverage for VoIP Services

If you’re new to offering VoIP one of the key considerations in preparing to launch phone service is rate center coverage. While you have global connectivity with an upstream Internet connection, this old telco world concept regarding local boundaries remains relevant and important when it comes to the telephone numbers you can offer.

Rate Center Definition

According to Wikipedia:

In the North American Numbering Plan, a rate center is a geographically-specified area used for determining mileage and/or usage dependent rates in the public switched telephone network.

Each rate center is associated with:

  • a geographical place name (city, province/state)
  • a nominal physical location (V and H co-ordinates) for distance calculations for billing purposes
  • one or more prefixes, in the form +1-NPA-NXX, which each identify a block of ten thousand directory numbers
  • a specified local calling area, identified as a list of other individual rate centers to which local or flat-rate landline calling is provided

There are over 15,000 rate centers in the U.S. A rate center does not necessarily map to a municipality exactly. A large city may have dozens of rate centers, while a rural area may see one rate center cover several towns. Local number portability allows a number to be moved to a different service provider.


A telephone number in the North American Numbering Plan consists of ten digits and is described as NPA-NXX-XXXX. N can be digits 2 through 9 and X can be any digit of 0 through 9.

NPA stands for Number Plan Area and is the area code. The next three digits are the prefix, which is the central office code. A central office is the telco building where legacy TDM equipment was housed and to which subscribers’ lines connected.

The last four digits are the four-digit station number.

Why it Matters

Rate center coverage is important to the overall customer experience and their willingness to take phone service from you. It assures that you can:

  • Port the local number already in use by your customer to your VoIP network
  • Provide your customers with a new local number (important for new businesses especially)
  • Enable your customers’ neighbors with legacy phone service to make a local call to your customer (as you’ll offer unlimited long distance it won’t matter to your customers if the call is local)

In order to have “coverage” in a rate center you need to become a competitive local exchange carrier (CLEC), sign interconnection agreements and build out physical TDM interconnects to that incumbent telco. And then manage the process to port numbers.

Or more easily: contract with a CLEC that already does all that.

Until such time as the entire PSTN has moved to a “flat” network with VoIP and the concept of geographical boundaries (LATAs) is obliterated, there is still a need to comply with the vestiges of the RBOC breakup of 1982.

As a result, making sure your VoIP solution has excellent rate center coverage as well as inventory of new numbers in your desired footprint is key. For our U.S. service provider customers we partner with Level 3 to provide nationwide coverage and support of over 90% of the U.S. population. Plus, we can build out to rate centers not on today’s list.

Porting Process

Once rate centers coverage is established, the porting process typically takes a few days (the duration will vary based on the preparedness of the other carrier surrendering the number being ported). There’s customer paperwork to handle and then the coordination with the losing provider.

We make porting very easy for service providers with our Cloud Voice Platform. During the account set-up process, we submit the request instantly to our carrier partners (using APIs) kicking off all that behind the scenes inter-carrier coordination. Our Admin Portal will then provide status information that allows service providers to plan other activities accordingly (e.g., scheduling an install at the customer premises).

If you’d like to learn more about launching and delivering VoIP services, let’s connect. We’d welcome the opportunity to talk with you.