NPA NXX - North American Telephone Database, …
Area Code,U.S. switching centers,NPA,NXX,Exchange,LATA,Telephone company,CLEC,CLLI Code, Number Portability,Vertical,Horizontal,Latitude Longitude, Mileage, NECA FCC Tariff #4, Voice Over IP, VOIP all in one package,Telecommunications Traffic, erlang, erlang b, extended erlang b, erlang c, …
