Crossposted from https://lemmy.blahaj.zone/post/48779421

I'm writing a program that can find info about a phone number. One problem appears to be that Google's phone number library doesn't provide enough info. For instance, take this number: +1 (613) 745-1576. My iPhone correctly says "Ottawa, Ontario, Canada", while Google's library doesn't return the city? How does my iPhone pick this up but not Google's own library? Is this provided by cell carriers? Is it something with the 745 block? If so, where can I find this info?

The (613) is the area code. That is specifically allocated for use in the Ottawa area. There are precise databases/maps. Of course, an area code can have very little with where one lives these days. I live in the Pacific Northwest and have an area code for the Midwest because that is where I was when I got my cellular phone.

The 745 is the 'exchange'. It was a way for an area code to be broken down into smaller groups. Sometimes that would be regions of a town/county/etc. or it could be for a large business, a University, government, etc.

One final note on the area code... there are a finite number of phone numbers that can be created within one area code. Sometimes a region's population/businesses will grow and create a shortage of phone numbers. When this happens the area covered by one area code will be restructured so that on area keeps the code and the rest of the area gets a new code.