Phone Numbers (#58) in the United States (#67 & #15) will have an area code relationship saved in the database. I'm going to use code as the primary field so it is easy to see what it is and here are some validation rules for it:
Allowed ranges: [2–9] for the first digit, and [0-9] for the second and third digits. When the second and third digits of an area code are the same, that code is called an easily recognizable code (ERC). ERCs designate special services; e.g., 800 for toll-free service. The NANP is not assigning area codes with 9 as the second digit.
drewroberts
commented
3 years ago
Phone Numbers (#58) in the United States (#67 & #15) will have an area code relationship saved in the database. I'm going to use
codeas the primary field so it is easy to see what it is and here are some validation rules for it:https://en.wikipedia.org/wiki/North_American_Numbering_Plan