If you are watching this video right now, there's a very good chance that your phone number looks like this.

It's ten digits long and written in a very predictable format.

At the beginning, you've got the three digit area code contained within parentheses, then a space, a three digit exchange number, a hyphen, and a four digit line number.

You probably know yours by heart, but have you ever stopped to consider why your phone number is your phone number?

Like, why is it those ten digits in that order?

Why is it ten digits at all?

Not nine or 11 or 12?

Well, in today's episode of, Noles Explores & Explains, we're going to be looking at the history of phone numbers and answering all those questions and more.

The telephone was, of course, invented by Alexander Graham Bell and debuted in the summer of 1876 at the Centennial Exposition in Philadelphia, alongside the typewriter and Heinz ketchup.

The first phones were pretty poor quality, the sound wasn't very loud and the range wasn't very far, but they were new and they were high tech, and so Americans loved them.

The first telephone networks, due to the impossibility of long distance calling, were centered around heavily populated places.

Towns and cities would operate their own independent systems out of a central office to which every phone in town was physically connected.

Say you wanted to give your friend a call on one of those old timey telephones.

You'd take it off the hook on the wall and you'd say, “Hello, Operator, give me Beulah or Esther or some other old person name.” And they'd say, right away, ma'am, and physically connect your phone line to theirs by moving pegs between holes in a board, manually switching pegs in a board, a manual switchboard.

Just three years later, as this new technology was sweeping the country, there was a measles outbreak in Lowell, Massachusetts.

A local doctor realized that if all four operators in town got sick or died, it would be next to impossible to retrain operators as to whose pegs and whose holes were whose.

So he had an idea.

Just assign every telephone a number.

Now Bell Telephone, the company which was spun up by Alexander Graham Bell and which was quickly buying up a lot of these independent systems, really didn't like the idea.

They thought it was beneath human dignity to just be a number.

Can you imagine that?

But eventually they relented because they realized he was right and the measles eventually went away.

But this telephone numbering scheme didn't.

Because phone service was inherently local and so few people actually had phones.

The first numbers were given numerically and sequentially, so somebody could have the phone number one.

Somebody else in town could have the phone number two, somebody else number three, so on and so forth.

By the end of the 19th century, there were still less than 100,000 phones in the entire world.

I have this coat hook here that my great grandma got ahold of during World War two.

It's from Redding, California, where she was living while my great-grandpa served overseas.

And I want you to pay attention to the phone number 99.

I was able to confirm with an old phone directory that this was, in fact, the entire phone number for this business.

Now, eventually, a system like this gets untenable, especially when it becomes possible to call other cities and towns.

But some more rural areas and even some small cities like Reading, were able to hold on to their local system for a long time.

In 1915, the first transcontinental phone call was made between New York City and San Francisco.

It was placed by the same two men who had made the very first ever telephone call, 38 years prior.

Bell and Watson.

But long distance calling was still expensive and very time consuming.

It could take up to 20 minutes to get connected, even if you were just calling the next state over.

That's because long distance calling was being done entirely by hand.

As operators in your city physically connected your call to operators in another city.

By 1920, there were over 150,000 operators in the United States, representing 2% of the entire female workforce.

Now, as we said before, every area that had telephone service had a central office, usually a large brick building near the edge of downtown to which all the telephones were physically connected with wires.

Each central office had multiple telephone exchanges within it.

Sometimes a small town just needed one exchange, while a large urban neighborhood could have several, and starting in the 19 teens and 20s, central offices began giving these exchanges names that would make it easier for you to remember your number and other people's numbers.

Sometimes these exchange names were of local significance, like the Schenley or Museum exchanges here in Pittsburgh, but more often than not, they were just pleasant sounding names that were easy to remember, like Cherry.

Now, these exchange names would be written as a prefix to your sequential phone number, but only the first three letters.

So an exchange named Tremont, for example, would be abbreviated to just TRE and then your phone number.

This was called the 3L-4N format.

Later on in the 1930s, these three letter exchange names were shrunk down to just two letters, and the vast majority of the country adopted the 2L-5N format, so TRE, for instance, would become TR.

This allowed for multiple telephone exchanges with the same name, and I know this seems counterintuitive, but this is what I mean.

There's a Glenn Miller song from the 1940s called Pennsylvania 6-5,000 Pennsylvania 6-5,000, because that was the phone number of the Hotel Pennsylvania in New York City.

Now, the exchange name in this instance is Pennsylvania.

But if you called Pennsylvania 5-5,000, well, that's a number on a different exchange.

And this was necessary because each telephone exchange could physically only hold up to 10,000 customer lines.

And that's the reason why the last part of your phone number, the line number, is four digits long.

0000 thru 9999 gives you 10,000 options.

This is my great grandfather's business card from the 1940s, after he got home from the war, showing his office telephone number.

Thornwall 5-4062.

You would read it aloud as Thornwall rather than just saying TH even though the operators knew.

That's all that mattered.

That's why they're capitalized.

And those two letters matter because they correspond to numbers on the newly invented rotary dial telephone.

But more on that in a minute.

First I want to show you what a central office looks like.

We still have them.

They just don't really matter as much as they used to.

This is the telephone building here in East Liberty, which historically has been one of Pittsburgh's most prominent neighborhoods.

It used to carry the Highland and Montrose Exchange, among others.

Most telephone buildings built in the 19 teens and 20s are this sort of toned down Renaissance style before they transitioned to Art Deco in the 1930s.

It doesn't really stick out that much architecturally, except for two major things.

First of all, the front door isn't really that prominent compared to how it would be in other office buildings of the era.

And second, it literally says Bell telephone above the doorway.

This building, like most other old telephone buildings in the area, are now owned by Verizon.

Since Verizon took over Bell's Mid-Atlantic services in the 1984 Bell breakup.

But that's a story for another time.

The history of phone numbers, as I'm sure you can tell, follows the technological advance of phones themselves.

Back in the early days, you had to talk to an operator because there was no way for you to dial a phone number yourself.

The rotary dial telephone was invented in 1892, but didn't pick up a lot of steam until the 1920s.

With the rotary dial, it was possible to, well, dial someone else's phone number without having to talk to an operator.

But this necessitated the invention of the automatic switchboard.

Now, the automatic switchboard was also invented in 1892 by a guy named Almon Strowger.

Strowger was an undertaker in a small town in the Midwest, and he felt like one of the operators in town was unfairly routing calls to his competition.

A man who happened to be her husband.

So he decided to invent a device which would automatically route local calls and thus put those crafty little operators out of business After World War Two, telephones became extremely widespread.

During the war, Bell telephone had introduced operator toll dialing, where you would tell the operators to dial long distance for you.

But pretty quickly, Bell realized that there would never be enough operators to keep up with that kind of demand, and that also those exchange names were getting a little bit out of hand.

So they would need to invent a way to automate the calling process.

And to facilitate that, they would have to introduce a standardized nationwide numbering system.

The first step, begun just after the war and not completed until the 1960s at least, was the standardization of exchange names.

In 1955, Bell Telephone put out a list of recommended exchange names.

Each was phonetically different enough to not be confused with others.

Old exchanges, however, could be grandfathered in.

You'll notice that the number series five, five, five, seven, nine five, and nine seven are reserved for special uses.

That's because there are no vowels mapped to those numbers on the rotary dial, so they were basically impossible to come up with good words for.

However, San Francisco had the Klondike exchange and Chicago had the Wrigley Exchange.

The next step, first unveiled in 1947 and perfected over the years, was the introduction of the North American Numbering Plan, or the NANP, which divided the US and Canada into 86 numbering Plan areas, or NPAs, each with their own three digit number.

The area code.

With the millions of telephones in the United States.

The country has to be divided too.

So the United States and Canada are divided into areas.

Each area has its own code number.

Area codes at first glance, seem to be just as random as central office numbers, maybe even more so.

But there is a rather ingenious set of rules underpinning the whole thing.

Bell Telephones Research Laboratory calculated there were 152 codes that were available to use, but at first they only needed 86.

And here's the map of those 86 numbering plan areas and the codes assigned to them in 1947.

Right away you'll notice some things.

First, no area codes cross state lines.

Easy enough.

Area codes do not start with zero, because if you dialed zero, you got the operator.

And they do not start with one either, because that was for dialing long distance.

If your state just had one area code like Montana, the middle digit was a zero, and if it had more than one like California, the middle digit was a one.

So within the area code itself is a clue to its relationship with other codes.

But by mandating the middle digit be a zero or a one, area codes became instantly recognizable from exchange names.

Think about it.

No exchange names could contain a zero or a one, because there are no letters mapped to those numbers and the ingenuity continues.

No NPAs that bordered each other had consecutive or near consecutive numbers.

303 is Colorado and 304 is West Virginia.

No easily mistaken numbers were near each other.

315 is upstate New York and 513 is southwest Ohio.

Any number ending in one one is out.

211, 311, 411, 511, 611, 711, 811, and 911 are what are called service codes.

They all provide essential societal services and so nobody can have them within their phone number 800 is out.

That's the toll free indicator as is 833, 844, 855, 866, 877, and 888.

All codes ending in zero zero indicate non-geographic functions.

988 is also out.

That's now the National Suicide Prevention Hotline, and 990 thru 999 are reserved for future use.

The most notable exception is 555.

Those are reserved solely for fictitious phone numbers in TVs, movies, and video games.

If anybody had those numbers in real life, they'd be bombarded with calls all day long.

That's the same reason nobody these days has the phone number.

8675309 You might notice on this map that Iowa has the same number of NPAs as California.

That's because the numbers were assigned according to telephone density, not population.

Phones first caught on in rural areas because everyone lived so far apart from each other.

But even though Iowa, for instance, had a high telephone density per capita, the greatest physical concentration of telephones were found in the big cities.

And because of the nature of the phone calls taking place in these cities, business and political affairs, it was determined that the best area codes should be given to the city's.

Best here means most efficient.

Let me demonstrate.

This is a rotary dial telephone.

More specifically, this is the Western Electric Model 500.

It's the classic desk telephone, introduced in 1950.

This one in particular belonged to the house that I grew up in in Beaver, Pennsylvania.

It was there when my parents moved in, and it's basically an empty shell.

I'm not racking up any charges here.

The rotary dial starts with a one in the upper right, and the numbers continue counterclockwise, with zero sitting at the bottom after nine.

That's the same reason that the zero is at the bottom of your smartphone dialing screen as well.

Old habits die hard.

Notice it has its own phone number written in the middle.

This was standard practice, and in this case it tells you a few things.

First, it was made after 1947 because it has an area code.

Secondly, it was made before 1998 because that area code is 412 and not 724.

And third, it was made after the 2L-5N system was phased out.

Beavers exchanges spruce four and spruce five had been operated out of the central office in nearby Rochester, Pennsylvania, but today, of course, spruce is just 77, and to this day, the majority of phone numbers in Beaver start with 774, or 775.

As you can see on that map of the original area codes, the most efficient area codes were assigned to the largest and most important cities.

So Chicago was the easy 312.

LA was the equally easy 213.

Washington was two.

Zero two.

Not quite so fast, but rules are rules.

New York City was 212 and the lowest number of all two.

Zero one was assigned to new Jersey, where Bell Labs was headquartered.

Alaska, meanwhile, got the time consuming nine zero.

Seven.

The first real test of these new area codes came just four years later, in 1951, with the introduction of direct distance dialing.

Now, the reason you probably haven't heard of direct distance dialing is because nowadays we just call it making a phone call.

With this new process, you could go to your phone and dial the other person's number, local or long distance directly without having to get an operator involved.

Here's how it works.

Let's say you want to call someone in Chicago.

VA 10339.

First, you find Chicago in a new area code handbook that you'll be given.

Here it is with a number 312.

312 is called the area code It will tell you why in a minute.

Oh, actually, we already went over that part.

Okay, now you dial one to get the long distance equipment.

Then you dial the area code number three, one two, then BA 10339.

Just as you would on a local call.

And that's all.

You've reached the Chicago number easily and without delay, simply by dialing one.

And an area code in this case three one, two.

Before you dial the regular telephone number.

The very first long distance call to be made with direct distance dialing occurred on November 10th, 1951.

Because it was located near Bell Labs, Englewood, New Jersey, became the first city in America to enjoy this new process, and with over 100 guests watching their mayor, M Leslie Denning dialed 415.

LA 39727.

And exactly 17 seconds later, his call was picked up by Frank Osborn, the mayor of Alameda, California.

The rest, as they say, is history.

Simple, wasn't it?

Can I just say I love how wholesome these educational videos from the 50s are?

Well, now, measles.

That's not so serious.

All kids get them sooner or later.

Oh, no.

Operators didn't go away overnight.

If you dialed a wrong number, for instance, and needed the charge reversed.

They were there to do that for you.

Or you could just call them for general information about things.

Operators would go on to work in a greatly reduced capacity until about 1978, in most parts of the country.

So DDD was finally in place nationwide by the late 1950s.

That's all she wrote, right?

Well, as evidenced by that video.

Area codes and exchange names co-existed for a while.

In 1958, the phone books began listing the exchange names just by their first two letters, no more words, and a few years after that, they began just listing them as the numbers that corresponded to no more letters at all.

So Thornwell five, for instance, became 845.

This was the introduction of all number calling or ANC.

And to quote from John Brooks “Definitive History of Bell Telephone”, “all number calling it is clear in hindsight stood in the minds of many for the age of the impersonal, when people live in huge apartment buildings, travel on eight lane highways, and identify themselves in many places -- Bank job, Income tax, return credit agency -- by numbers...” So much for numbers being beneath human dignity.

ANC wasn't fully implemented until the 1980s in some rural areas, and the last of those 152 original area codes wasn't assigned until 1993.

It was 610 for Philadelphia.

Today, there are more than 480 area codes in use, with nine having been assigned in 2025 alone.

In the 1980s, Bell finally allowed two through nine to be used for the middle digit, opening up 640 new options.

But even before this, as states had begun to outgrow their single area code, that middle digit pattern had become untenable.

But there are still rules in place for when new codes are assigned.

For instance, they cannot be too similar or sequential to neighboring area codes, nor can they be too similar to existing prefixes in that area.

By my calculation, there are still 131 area codes up for grabs from 1947 to 1992.

The only way to get a new area code was a split.

That's when you split a numbering plan area, and one part retains the existing area code, and one part gets a new one.

Usually, the original area code shrinks to cover the densest part of the territory.

Case in point 206 used to cover the entirety of Washington State, but now only covers part of the Seattle region.

Since 1992 and exclusively since 2007, we've been overlaying new area codes on top of existing ones.

So 206, which covers Des Moines up to Shoreline, is now sharing that space with 564, which was overlaid in June 2025.

That doesn't mean people with a 206 area code have to change their numbers.

It just means that any new numbers can be drawn from two pools, and since 206 is close to being exhausted, soon all new Seattle customers will have a 564 number For a long time, if you are making a local call that is one within the same area code, you only had to dial seven digits.

I've got a yardstick here, manufactured by a hardware chain in the Seattle area that has a list of all their locations and all their phone numbers.

Now, when this was made, all of these locations had a 206 area code, and I'm assuming that most of their customer base did as well.

And that's why they didn't bother to print 206 on here, because nobody had to dial it anyway.

However, in the 1990s, when they began overlaying area codes, it suddenly became possible that you could have two people in the same city with the exact same phone number.

The only difference being the area code.

So to prevent wrong numbers from being dialed all the time, the FCC began mandating ten digit dialing in all areas with overlays, partially as an expansion of this, and partially because of the adoption of 988 as the National Suicide Prevention Hotline, the FCC in 2022 mandated nationwide ten digit dialing.

Even with all these changes, however, it's estimated North America could run out of phone numbers as soon as 2050.

The last major change to take place for phone numbers might actually be the most fundamental.

All of the previous changes that we've talked about in this video were technological feats, to be sure, but they were still grounded in the inherent geography of the technology.

If you lived in Montana, your area code was 406, and there wasn't a thing you could do about it.

But with the rise of cellular technology.

Phone numbers have been all but untethered from their intensely local origins.

Number portability, or the ability to take your phone number with you when you move houses or even across the country, wasn't really a big thing until the 1990s, and it wasn't even required of carriers to let you do it until 2003.

But think about it.

How many people do you know?

How many contacts do you have in your list?

Or coworkers or neighbors who move from elsewhere and have a completely different area code than you?

The Hotel Pennsylvania in New York City closed in 2020 and was demolished in 2023.

It had that phone number Pennsylvania 6-5000.

Pennsylvania 6-5000 or less romantically 212-736-5000, for nearly a century, making it one of the longest continually used phone numbers in American history.

The developers of the site have said they plan to reuse it in some way in their new office development, but have been pretty vague about how.

But let's face it, the era of catchy phone numbers is pretty much over.

Sure, you'll still see them on billboards, especially when businesses pay to have one that spells out their company name, but otherwise phone numbers are pretty forgettable.

Dare I say, meaningless?

How many do you have memorized off the top of your head?

How many of you still use a Rolodex or buy a phonebook?

We can just Google any phone number we want, and there's no guarantee that those phone numbers will be geographically associated at all to the people or businesses they represent.

The first pushbutton telephone, the Touchstone, was unveiled at the 1962 World's Fair.

It took a while to catch on, but nowadays it just seems perfectly natural to push buttons instead of using one of these things.

But the rotary dial does live on.

After all, that's why we still say we dial a phone number So maybe there's something to be said for the physical act of dialing a telephone number with letters in the middle of it.

Maybe it helps us remember those numbers and those people all the better.

Maybe it helps us feel more in touch with our community.

Maybe there's dignity in that.

And maybe I'm full of hot air.

And at the end of the day, they really are just numbers.

But I want to know what you think.

Do you remember your phone number from childhood?

Does the phone number you have now accurately represent where you live?

Is it just me, or was the 2L-5N system really cool?

Let me know anything you want to let me know in the comments down below.

I really do read every single one.

And while you're down there.

Check out some of the links I put in the description.

There was so much that I couldn't include in this video, but if you want to know more, that's a great place to start.

Thank you so much for watching and I'll see you next time.