About Area Codes

On a daily basis, you most likely dial an area code several times. These three, little numbers become ingrained into our memories and habits and we intrinsically come to identify area codes with certain places, people, and times in our lives. But while area codes are everywhere, most people know surprisingly little about them. Area codes have a rich history in the United States and continue to evolve and affect our lives in a multitude of ways that we may not even realize. Going back all the way to the 1940s, area codes have helped us create an intricate national network of telephones that continue to support our ever expanding communication needs.

A brief history of area codes

The history of the area codes is a fascinating one. Area codes started as a way for Bell to expand their telephone network into the monolith it is today. However, for the company to do that, they needed to figure out a way to go beyond the need for human operators. Before area codes were in place, human operators patched individual calls through to where they needed to go, but that wasn’t going to work on a national scale. Instead, a three-digit prefix was created that signalled to the line what central station the phone call was going to be routed through.

What is an area code?

That prefix was, of course, the area code we are all familiar with today—but what is an area code? What do those three numbers signify?

Area codes are part of a telephone numbering plan that is used to assign unique telephone numbers to subscriber telephones. Basically, telephone numbers are the addresses of each person or endpoint on a telephone network. For these addresses to work, the geographic location of an endpoint has to be marked. To do this, the territory of service a telephone system covers is divided into distinct regions. Each of these regions is then assigned a prefix, called an area code. The area code is one of the most important parts of the telephone number when it comes to calling someone, since it allows the system to understand where in the service area the call has to first be routed to.

Look at it like this; your area code is like a zip or postal code. It allows the system to quickly and effectively sort the calls into what area they are supposed to be delivered to. From there, the rest of the number is directed through more granular locations until it rings in your home.

How do cell phone area codes work?

The “address” of your phone is all well and good, until your phone starts to move. Cell phones use the same area code system as landlines, and they assigned by the region the cell phone is activated in. That being said, cell phones did mean one thing for the North American Numbering Plan Administration (NANPA), and that was that they were going to need a whole lot more phone numbers. When cell phones started gaining popularity, it meant that the average household suddenly needed two, three, four, or even five phone numbers. Suddenly, many locations started needing a lot more area codes to assign all those new numbers, which is why some regions have over a dozen area codes to accommodate the population size and all those phone numbers.

Other area codes and their purpose

Area codes aren’t the only prefixes in use in our telephone system. There are several other codes that most of us are familiar with, but may not know the names for. These include N11 codes, non-geographic codes, and expansion codes—but what does this other pool of codes do, exactly?

Well, that depends entirely on the code. Here’s a quick explanation of each of these codes to give you some clarity:

N11 Codes: these are service codes, commonly called N11 codes because of their format (random digit followed by 1-1). These codes allow phone users quick, three-digit access to special services, the most recognized being 911, for emergency services. There is also 411 for local directories, 311 for non-emergency or municipal government services, and 511 for weather services, traffic information, or sometimes police non-emergency services. These codes are public use and there are standards in place as to when a new one needs to be created and certain criteria that needs to be met showing sufficient demand.

Non-geographic codes: 99% of phone numbers exist in one, subdivided region, signified by their area code. However, there are sets of numbers that have no assigned location. These are known as non-geographic numbers or virtual numbers. These numbers are assigned to a country, but not to any one location within the country. When someone calls one of these numbers, the call will automatically be transferred to a subscriber’s telephone—no matter where that telephone is located. This can be a wireless phone, or a landline.

Expansion codes: NPAs have rules for numbering. For example, 0 and 1 can’t be used as the leading digits for area codes and central office codes. Any NPAs that have a 9 as the second digit are expansion codes. These codes are reserved for future format expansion. These expansions would mean that the typical ten digit phone number would be expanded to eleven digits overall to accommodate for population growth.

Fun facts about area codes

You probably never thought there was so much to learn about area codes, but the history of our telephone numbering system is quite extraordinary, and that system continues to evolve.

We leave you with some fun area codes to keep your mind working every time you pick up the phone:

  • The first area code put in place in the United State was New Jersey’s 201 area code, established in 1951.
  • Service codes change when you leave North America, which means the 911 that has been ingrained into so many people does not apply when you’re not in NANPA territory.
  • In North American films and television, there are area codes and phone numbers set aside for fictional use that will not be assigned to anyone. The most popular? 555-5555.
  • There are 317 geographic area codes in the United States and 18 non-geographic codes.
  • Countries that are not part of NANPA do not use the 3 digit area code + 7 digit local number structure for telephone numbers.