How the Telephone Was Invented

Alexander Graham Bell's first telephone
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In the 1870s, Elisha Gray and Alexander Graham Bell independently designed devices that could transmit speech electrically. Both men rushed their respective designs for these prototype telephones to the patent office within hours of each other. Bell patented his telephone first and later emerged the victor in a legal dispute with Gray.

Today, Bell's name is synonymous with the telephone, while Gray is largely forgotten. However, the story of who invented the telephone goes beyond these two men. 

Bell's Biography

Alexander Graham Bell was born on March 3, 1847, in Edinburgh, Scotland. He was immersed in the study of sound from the beginning. His father, uncle, and grandfather were authorities on elocution and speech therapy for the deaf. It was understood that Bell would follow in the family footsteps after finishing college. But after Bell's two other brothers died of tuberculosis, Bell and his parents decided to immigrate to Canada in 1870.

After a brief period of living in Ontario, the Bells moved to Boston where they established speech-therapy practices specializing in teaching deaf children to speak. One of Alexander Graham Bell's pupils was a young Helen Keller, who when they met was not only blind and deaf but also unable to speak.

Although working with the deaf would remain Bell's principal source of income, he continued to pursue his own studies of sound on the side. Bell's unceasing scientific curiosity led to the invention of the photophone, significant commercial improvements in Thomas Edison's phonograph, and to the development of his own flying machine just six years after the Wright Brothers launched their plane at Kitty Hawk. As President James Garfield lay dying of an assassin's bullet in 1881, Bell hurriedly invented a metal detector in an unsuccessful attempt to locate the fatal slug.

From Telegraph to Telephone

The telegraph and telephone are both wire-based electrical systems. Alexander Graham Bell's success with the telephone came as a direct result of his attempts to improve the telegraph. When he began experimenting with electrical signals, the telegraph had been an established means of communication for some 30 years. Although a highly successful system, the telegraph was basically limited to receiving and sending one message at a time.

Bell's extensive knowledge of the nature of sound and his understanding of music enabled him to consider the possibility of transmitting multiple messages over the same wire at the same time. Although the idea of a "multiple telegraph" had been in existence for some time, it was purely conjecture as no one had been able to fabricate one—until Bell. His "harmonic telegraph" was based on the principle that several notes could be sent simultaneously along the same wire if the notes or signals differed in pitch.

Talk With Electricity

By October 1874, Bell's research had progressed to the extent that he could inform his future father-in-law, Boston attorney Gardiner Greene Hubbard, about the possibility of a multiple telegraph. Hubbard, who resented the absolute control then exerted by the Western Union Telegraph Company, instantly saw the potential for breaking such a monopoly and gave Bell the financial backing he needed.

Bell proceeded with his work on the multiple telegraph but did not tell Hubbard that he and Thomas Watson, a young electrician whose services he had enlisted, were also developing a device that would transmit speech electrically. While Watson worked on the harmonic telegraph at the insistent urging of Hubbard and other backers, Bell secretly met in March 1875 with Joseph Henry, the respected director of the Smithsonian Institution, who listened to Bell's ideas for a telephone and offered encouraging words. Spurred on by Henry's positive opinion, Bell and Watson continued their work.

By June 1875, the goal of creating a device that would transmit speech electrically was about to be realized. They had proven that different tones would vary the strength of an electric current in a wire. To achieve success, therefore, they needed only build a working transmitter with a membrane capable of varying electronic currents and a receiver that would reproduce these variations in audible frequencies.

"Mr. Watson, Come Here"

On June 2, 1875, while experimenting with the harmonic telegraph, the men discovered that sound could be transmitted over a wire completely by accident. Watson was trying to loosen a reed that had been wound around a transmitter when he plucked it by accident. The vibration produced by that gesture traveled along the wire into a second device in the other room where Bell was working.

The "twang" Bell heard was all the inspiration that he and Watson needed to accelerate their work. They continued to work into the next year. Bell recounted the critical moment in his journal: "I then shouted into M [the mouthpiece] the following sentence: 'Mr. Watson, come here—I want to see you.' To my delight, he came and declared that he had heard and understood what I said."

The first telephone call had just been made.

The Telephone Network Is Born

Bell patented his device on March 7, 1876, and it quickly began to spread. By 1877, construction of the first regular telephone line from Boston to Somerville, Massachusetts, had been completed. By the end of 1880, there were over 49,000 telephones in the United States. The following year, telephone service between Boston and Providence, Rhode Island, had been established. Service between New York and Chicago started in 1892 and between New York and Boston in 1894. Transcontinental service began in 1915. 

Bell founded his Bell Telephone Company in 1877. As the industry rapidly expanded, Bell quickly bought out competitors. After a series of mergers, the American Telephone and Telegraph Co.—the forerunner of today's AT&T—was incorporated in 1880. Because Bell controlled the intellectual property and patents behind the telephone system, AT&T had a de facto monopoly over the young industry. It would maintain its control over the U.S. telephone market until 1984 when a settlement with the U.S. Department of Justice forced AT&T to end its control over state markets.

Exchanges and Rotary Dialing

The first regular telephone exchange was established in New Haven, Connecticut, in 1878. Early telephones were leased in pairs to subscribers. The subscriber was required to put up his own line to connect with another. In 1889, Kansas City undertaker Almon B. Strowger invented a switch that could connect one line to any of 100 lines by using relays and sliders. The Strowger switch, as it came to be known, was still in use in some telephone offices well over 100 years later.

Strowger was issued a patent on March 11, 1891, for the first automatic telephone exchange. The first exchange using the Strowger switch was opened in La Porte, Indiana, in 1892. Initially, subscribers had a button on their telephone to produce the required number of pulses by tapping. Then an associate of Strowgers' invented the rotary dial in 1896, replacing the button. In 1943, Philadelphia was the last major area to give up dual service (rotary and button).

Pay Phones

In 1889, the coin-operated telephone was patented by William Gray of Hartford, Connecticut. Gray's payphone was first installed and used in the Hartford Bank. Unlike pay phones today, users of Gray's phone paid after they had finished their call.

Payphones proliferated along with the Bell System. By the time the first phone booths were installed in 1905, there were about 2.2 million phones; by 1980, there were more than 175 million. But with the advent of mobile technology, the public demand for payphones rapidly declined, and today there are fewer than 500,000 still operating in the United States.

Touch-Tone Phones

Researchers at Western Electric, AT&T's manufacturing subsidiary, had experimented with using tones rather than pulses to trigger telephone connections since the early 1940s, but it wasn't until 1963 that dual-tone multifrequency signaling, which uses the same frequency as speech, was commercially viable. AT&T introduced it as Touch-Tone dialing and it quickly became the next standard in telephone technology. By 1990, push-button phones were more common than rotary-dial models in American homes.

Cordless Phones

In the 1970s, the very first cordless phones were introduced. In 1986, the Federal Communications Commission granted the frequency range of 47 to 49 MHz for cordless phones. Granting a greater frequency range allowed cordless phones to have less interference and need less power to run. In 1990, the FCC granted the frequency range of 900 MHz for cordless phones.

In 1994, digital cordless phones were introduced, followed by digital spread spectrum (DSS) in 1995. Both developments were intended to increase the security of cordless phones and decrease unwanted eavesdropping by enabling the phone conversation to be digitally spread out. In 1998, the FCC granted the frequency range of 2.4 GHz for cordless phones; the upward range is now 5.8 GHz.

Cell Phones

The earliest mobile phones were radio-controlled units designed for vehicles. They were expensive and cumbersome, and had extremely limited range. First launched by AT&T in 1946, the network would slowly expand and become more sophisticated, but it never was widely adopted. By 1980, it had been replaced by the first cellular networks.

Research on what would become the cellular phone network used today began in 1947 at Bell Labs, the research wing of AT&T. Although the radio frequencies needed were not yet commercially available, the concept of connecting phones wirelessly through a network of "cells" or transmitters was a viable one. Motorola introduced the first hand-held cellular phone in 1973.

Telephone Books

The first telephone book was published in New Haven, Connecticut, by the New Haven District Telephone Company in February 1878. It was one page long and held 50 names; no numbers were listed, as an operator would connect you. The page was divided into four sections: residential, professional, essential services, and miscellaneous.

In 1886, Reuben H. Donnelly produced the first Yellow Pages-branded directory featuring business names and phone numbers, categorized by the types of products and services provided. By the 1980s, telephone books, whether issued by the Bell System or private publishers, were in nearly every home and business. But with the advent of the Internet and of cell phones, telephone books have been rendered largely obsolete. 


Prior to 1968, there was no dedicated phone number for reaching first responders in the event of an emergency. That changed after a congressional investigation led to calls for the establishment of such a system nationwide. The Federal Communications Commission and AT&T soon announced they would launch their emergency network in Indiana, using the digits 9-1-1 (chosen for its simplicity and for being easy to remember).

But a small independent phone company in rural Alabama decided to beat AT&T at its own game. On Feb. 16, 1968, the first 9-1-1 call was placed in Hayleyville, Alabama, at the office of the Alabama Telephone Company. The 9-1-1 network would be introduced to other cities and towns slowly; it wasn't until 1987 that at least half of all American homes had access to a 9-1-1 emergency network.

Caller ID

Several researchers created devices for identifying the number of incoming calls, including scientists in Brazil, Japan, and Greece, starting in the late 1960s. In the U.S., AT&T first made its trademarked TouchStar caller ID service available in Orlando, Florida, in 1984. Over the next several years, the regional Bell Systems would introduce caller ID services in the Northeast and Southeast. Although the service was initially sold as a pricey added service, caller ID today is a standard function found on every cell phone and available on almost any landline.

Additional Resources

  • Casson, Herbert N. The History of the Telephone. Chicago: A.C. McClurg & Co., 1910.
View Article Sources
  1. "1870s to 1940s - Telephone." Imagining the Internet: a History and Forecast. Elon University School of Communications.

  2. Kieler, Ashlee. “5 Things We Learned About Pay Phones & Why They Continue To Exist.” Consumerist, 26 Apr. 2016.

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Bellis, Mary. "How the Telephone Was Invented." ThoughtCo, Apr. 5, 2023, Bellis, Mary. (2023, April 5). How the Telephone Was Invented. Retrieved from Bellis, Mary. "How the Telephone Was Invented." ThoughtCo. (accessed June 3, 2023).