NANPA and LocalCallingGuide - Best new friends?
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