The history of phone numbers

Almost everyone has one. No, not an opinion… a phone number. And it’s been that way for a while now. But before we all had ten digits next to our names in someone’s contact list, we had seven digits next to our names in someone’s Rolodex, and before that we had… well, let’s get into it. In this blog we’ll dig into the history of phone numbers: why they were invented, how they were developed and how the system works. So sit back and dial in.

When were phone numbers invented?

The first telephone numbers were invented in Lowell, MA in 1879. At this point, calling someone required having a switchboard operator manually connect you to them, and Lowell had four switchboard operators working at the time. Local physician Dr. Moses Greeley Parker, feared that these operators may fall ill due to a measles epidemic, and suggested assigning numbers to Lowell residents so that any substitute switchboard operators would have an easier time taking over. And just like that, Dr. Moses Greeley Parker invented telephone numbers. This also means he’s kinda responsible for spam calls, but we’ll let that slide.   

What did the first phone numbers look like?

Before direct-dialing became a thing, switchboard operators would still assist with connecting calls. You’d pick up the phone, ask the operator to connect you to “Minty-315” for example, and the operator would get them on the line for you. This continued into the early 1900s, but as service areas started to grow, networks began to expand, and more people made more phone calls, it became clear that the system itself needed to evolve.

The rise of phone numbers

As telephone systems continued to grow, so too did the need for more telephone numbers. Initially, long distance calls weren’t possible—you could only be connected to other people in your service area. The numbers linked to names (like our Minty-315 example) came in the early 1900s, and that evolved to an alphanumeric two letters + five numbers system in the 1920s, around the same time mechanical dialers replaced human switchboard operators. The two letters in each phone number represented a specific service area. Those are the letters you still see on your phone’s dialing keypad today. For example, if you lived in Springfield, your home phone number may be SP4-3298 (or 774-3298).

At this point, there were several localized networks across the country, each with its own unique phone number system. The system as a whole was not very organized, and it became clear that we needed a standardized approach to connecting the local networks, especially if we wanted to make long-distance calls possible. Enter the North American Numbering Plan.  

Introduction of the North American Numbering Plan (NANP) 

Originally known as the Nationwide Numbering Plan, the North American Numbering Plan was launched in 1947 as a unified system for assigning phone numbers in an effort to increase efficiency and to enable us to make long-distance calls. North America was divided into 86 different “Numbering Plan Areas,” and each of them was given a different three-digit code. Ludacris fans know where we’re going with this. 
These three-digit “area codes” would come first, followed by a three-digit prefix, representing a smaller region within the Number Planning Area. Then the last four digits were the “line number,” allowing for 10,000 different lines per prefix (e.g. every number from 0000 to 9999). This could give us up to ten billion (with a b) possible ten-digit numbers, but for now it only adds up to hundreds of millions of existing ten-digit numbers.

The rise of cell phones (and the need for more numbers)

As cell phones became more popular in the late 80s into the 90s, and texting started to take off (everyone’s favorite wireless pastime), it became clear that we needed to expand our phone number capacity. The evolution of our phone number system included:

Overlay area codes

Some cities in America have more phones than there are available seven-digit numbers, which resulted in the need for overlay area codes. This is when an additional area code is added to an existing Number Planning Area, and any new lines activated in that region will likely be assigned the new area code. This happened for the first time in 1992 in NYC when 917 was added to the five boroughs. Los Angeles residents may remember the addition of the 424 area code back in ‘06 and the resulting shame that came from not having a 310 number.

Split area codes

Before overlaying area codes, the only way to add more phone numbers to a local pool was to split the area code. Half the area would keep their existing phone numbers, and the other half would be given a new area code. This, of course, was a bit of a headache and we stopped doing this in 1992.  

Number portability

The ability to keep your phone number while switching phone carriers, AKA porting your number, was introduced in the early 90s to promote competition among phone providers. Before this, customers were forced to stay with their current carrier or lose their phone number. Portability allowed other carriers to compete fairly with a focus on their prices and service (much to the chagrin of some larger companies). That’s why the FCC mandated number portability in the US starting in 1996 with the Telecommunications Act. So now you can keep your number when you switch carriers (like if you want to pay significantly less with Mint Mobile, perhaps). 

Phone numbers in the 21st Century 

The demand for more wireless numbers continues to grow and with it, the NANP continues to evolve. From just a few digits that only allowed you to speak to someone down the street to their current role connecting people across the globe, the history of phone numbers reflects the remarkable evolution of communications technology—and we hope you enjoyed learning all about it. If you’re still in an educational mood, feel free to check out the history of cell phones or to learn more about when exactly texting started. Ready to make that overpriced wireless bill ancient history? Mint Mobile runs on the nation’s largest 5G network (and the FCC says you can bring your number). Click below to see why switching to Mint Mobile just makes sense.