When we dial or save a phone number—whether landline or mobile—we rarely think about it: it feels like numbers have always existed and are the most logical solution. How else could it be? Or could it?
In reality, phone numbers entered humanity’s life gradually, along with the development of telephony. Yes, they have their own fascinating history.
No Numbers At All
The telephone, as we know it today, was patented by Alexander Graham Bell in early 1876. History preserved the first words ever spoken over the phone: “Mr. Watson, come here, I want to see you!”.
At that moment there were only two devices connected by a single wire. The invention quickly caught on, however. Soon there were many devices, many wires, and a need for private conversations. That’s when switchboards appeared.
Technically, these were bundles of wires that an operator could connect manually. To know which wire went to whom, the caller simply named the person. In small towns with just a handful of subscribers, the human operator easily remembered everyone and made the right connection.
For example, Boston’s first telephone network served only 778 subscribers and you could literally ask for someone by surname. However, as networks grew, similar surnames, duplicates, and sheer volume made it impossible to rely on memory alone. Order was desperately needed.
The Birth of Numbers
According to one popular story, the decisive push came from… an illness. In 1878, a measles epidemic in New Haven, USA, knocked out most telephone operators. Their inexperienced replacements couldn’t remember thousands of names, and chaos ensued.
Legend has it that a local doctor suggested replacing names with numbers. The first telephone directory listed about 50 entries such as “11” for the drugstore or “23” for the police. The idea took off immediately.
Until the end of the 19th century, phone numbers remained very short. In 1880s New York, three- or four-digit numbers were common. Around the same time, the precursor to the rotary dial appeared.
Letters and Digits
By the late 19th century, numeric phone numbers had become the standard.
Later, to make numbers easier to remember, letters were mapped onto digits—the system still visible on keypads today: 2 = ABC, 3 = DEF, etc.
This allowed “vanity” numbers. For example, PEnnsylvania 6-5000 (using the first two capital letters) corresponded to 736-5000. That very number, belonging to the Hotel Pennsylvania in New York, has been in continuous use since 1919 and is the world’s oldest still-active phone number.
Other countries also used letters, though less creatively. In the 1930s Soviet Union, the format was something like “A1-23-45”.
Automation
The first automatic telephone exchange was invented in 1888 by undertaker Almon Strowger. Legend has it he grew suspicious when a human operator kept routing his calls to a competitor, so he created the grandfather of all modern automatic switches.
The very first fully operator-less telephone exchange opened not in the USA but in Germany in 1919.
Another major American contribution was tone dialing (DTMF). In the 1960s push-button tone dialing replaced the slow rotary dial and was many times faster.
Globalization
People soon wanted more than local calls—why not ring another country or even another continent?
In 1960 the International Telecommunication Union (ITU) standardized country codes: +1 for North America, +44 for the United Kingdom, +7 for the USSR and so on.
The Mobile Era
Mobile phones didn’t fundamentally change the numbering system. Countries simply assigned new prefixes to mobile networks, treating them like additional local exchanges.
Technologically, however, mobiles revolutionized everything. Within a decade, analog radio gave way to the GSM digital standard.
Today’s devices have evolved so far that their original purpose—making voice calls—feels almost secondary. Modern flagship smartphones are pocket-sized computers that can rival laptops and even desktops in power and functionality.
Yet the humble phone number and its country-code system remain the backbone of voice communication worldwide.