Confused about dial plans in the US? – Here is the solution
These 2 sites will help you get the most out of any North America dial-plan based on Areacode
Lets begin with NANPA: https://www.nationalnanpa.com/
Going into Tools and Area Code Search you can get a lot information
Here is an example:
Pay close attention to the Dialing Plan for this NPA section. This will dictate the way you can make calls out locally and nationally. In case you are interested in FPA HNPA, NPA and NXX terms, here is a good link: https://en.wikipedia.org/wiki/North_American_Numbering_Plan
Or, for the condensed version read the followoing:
Things to understand from the previous image:
- Home NPA Local Calls- These are calls that are considered local within the NPA that you searched on.
- Foreign NPA Local Calls – These are calls outside of the home NPA that would be considered local calls.
- Home NPA Toll Calls – These are calls that result in Toll charges (Long Distance).
- Foreign NPA Toll Calls – These are calls to NPAs outside of the Home NPA that result in Toll Charges.
- Standard – This are considered the normal dialing pattern for the NPA..
- Permissive –This is considered a temporary or transitory dialing pattern for a NPA, which is typical of a NPA transitioning from 7 digit dialing to 10 digit local dialing.
- 7D – Calls can be completed by dialing a 7 digit number consisting of the 3 digit Office Code and the 4 digit Extension.
- 10D – Calls can be completed by dialing a 10 digit number consisting of the 3 digit NPA, 3 digit Office Code and 4 digit Extension.
- 1+10D – Calls can be completed by dialing the 11 digit number consisting of the Country code (in this example 1 since we are dealing with the NANPA), 3 digit NPA, 3 digit Office Code and 4 digit Extension.
Now The local Calling Guide will give you a better search on the actual numbers per NPA and NXX: http://localcallingguide.com/lca_prefix.php?npa=305&nxx=321&x=&ocn=®ion=&lata=&switch=&pastdays=&nextdays=
This link also will help you get an XML file with all the Home NPAs and Foreign NPAs on a particular number:
Make sure you change npa=XXX and nxx=XXX to the numbers you are interested in looking
About the Author:
Andres Sarmiento, CCIE # 53520 (Collaboration)
With more than 13 years of experience, Andres is specialized in the Unified Communications and Collaboration technologies. Consulted for several companies in South Florida, also Financial Institutions on behalf of Cisco Systems. Andres has been involved in high-profile implementations including Cisco technologies; such as Data Center, UC & Collaboration, Contact Center Express, Routing & Switching, Security and Hosted IPT Service provider infrastructures.