212 is New York, while the relatively close Boston got 617. 213? Across the country, to Los Angeles. How’s this happen?
The answer is pictured at the right. It’s all because of the rotary phone.
Before 1951, long distance phone calls required an operator’s assistance. On November 10, 1951, that ended, as the mayor of Englewood, New Jersey dialed, directly, the major of Alameda, California. (The call took 18 seconds to connect.) In order to get to that point, however, the phone system infrastructure required overhaul; specifically, the addition of a routing system. Enter area codes.
Until recently, all area codes had either a “1” or a “0” as the middle number. This allowed for local calls to be dialed without the area code, as the switching software would recognize a long distance call by the second digit — local exchanges never had a 0 or 1 in that spot — and avoid confusion. But the etymology of specific area codes is more complicated. While ZIP codes are roughly geographic (there’s a map for that) though, area codes clearly aren’t, as New York (originally only 212) isn’t near Los Angeles (213) and Detroit (313) abuts neither Chicago (312) nor St. Louis (314).