Why do we need area codes?
When the inventor of the telephone, Alexander Graham Bell, made the first ever phonecall, it was just to the next room. His assistant picked it up, heard the words: "Mr Watson, come here, I want to see you" and that was it.
The date was 10 March 1876. One year later, in 1877, Mr Bell made the first ever long-distance call. He was in Salem, Massachussets, and Mr Watson answered the call in Boston, the capital of the same state.
Nowadays, millions and millions of phone calls are made every day in USA, criss-crossing a vast country. The digits tapped rather than dialled on smartphones are quite long, but they all have something in common
The very first three digits, the "area code" indicate a certain geographic area, served by a telephone network.
It can be a whole state, such as Montana, with its iconic 406 area code, or just a part of a state. California currently has 38 area codes (source https://www.cpuc.ca.gov/areacodes/). It started with 3 in 1947, when the North American Numbering Plan was created.
The story of this system, based on the idea of replacing switchboards and operator dialling with direct calls, is a story of successful automation. Like any engineering feat, it had to be rigourous and reflecting reality. Populous places, with more scope for phone usage growth, were assigned more area codes.
