The history
From a voice on a string to calls as packets of light: 150 years of talking at a distance.
People dreamed of sending a voice along a wire long before anyone managed it. In the 1870s several inventors raced to do it, and Alexander Graham Bell won the patent. Then came the harder part: loud microphones, exchanges to connect everyone, switches that counted your dial pulses, cables under oceans, and finally digital voices, fibre and the internet. India joined early, in 1882, and in the 1980s and 90s built its own exchanges and filled its streets with yellow STD booths.
1876
Telephone patent
Alexander Graham Bell, USA
1878
Commercial telephone exchange
George W. Coy, New Haven, USA
1878
Woman telephone operator
Emma Nutt, Boston, USA
1882
Telephone exchange in India
Oriental Telephone Company, Calcutta
1892
Automatic exchange
La Porte, Indiana, USA
1956
Transatlantic telephone cable
TAT-1, Scotland to Newfoundland
1960
Subscriber trunk dialling in India
Lucknow to Kanpur
1963
Touch-tone service
Bell System, Pennsylvania, USA
1660 – 1876
Scientists and tinkerers show that sound can travel along a string or a wire, and several inventors try to send speech by electricity.
1667
c. 1665–1667
The English scientist Robert Hooke described how sound could be carried far along a tight wire or string, much further than through the air. It is the idea behind the tin-can telephone that children still make.
Why it mattered. Long before electricity, people knew a solid line could carry a voice.
1861
26 October 1861
The German teacher Philipp Reis showed a device he called the Telephon. It sent musical tones, and by some accounts a few words, down a wire. Historians still argue about how well it carried speech.
Why it mattered. It gave the telephone its name, 15 years before Bell's patent.
1871
28 December 1871
The Italian inventor Antonio Meucci had been working on a talking telegraph, his telettrofono, for years. Too poor to pay for a full patent, he filed a cheaper caveat in 1871 and let it lapse in 1874. In 2002 the US House of Representatives passed a resolution saying his work in the invention of the telephone should be acknowledged. Who deserves the most credit is still debated.
Why it mattered. The telephone had several parents, and not all of them got the credit.
1876 – 1880
Bell patents the telephone, and carbon microphones make calls loud enough to be useful.
1876
14 February – 7 March 1876
Bell's lawyer filed his patent application on 14 February 1876, the same day Elisha Gray filed a caveat for a similar idea. US patent 174,465 was granted on 7 March. Three days later Bell spoke the first words over his liquid transmitter: 'Mr. Watson, come here, I want to see you.'
Why it mattered. It was one of the most valuable patents ever, and the start of the Bell telephone companies.
1877
1877–1878
Early telephones were faint. Thomas Edison filed a patent in 1877 for a transmitter that used carbon, whose resistance changes when pressed. David Edward Hughes showed a carbon 'microphone' in London in 1878, and many historians credit him with the idea. Carbon microphones were used in telephones for about a hundred years.
Why it mattered. The carbon microphone let a voice control a battery's current, making calls loud enough to be practical.
1878 – 1920
Exchanges connect whole towns, and operators, mostly women, join calls by hand with plugs and cords.
1878
28 January 1878
George Coy opened the first commercial telephone exchange, with 21 subscribers. His switchboard was built from carriage bolts and wire from ladies' bustles, and could connect two conversations at a time.
Why it mattered. For the first time you could call anyone on the exchange, not just one other phone.
1878
1 September 1878
Early operators were teenage boys, who were often rude to callers. Emma Nutt was hired as the first woman operator, and her sister Stella started a few hours later. Within a few years, switchboards everywhere were run by women.
Why it mattered. Operating the switchboard became one of the first big jobs open to women.
1882 – 2000
From Calcutta's 93 subscribers to STD dialling, C-DOT's own exchanges and a booth on every corner.
1882
28 January 1882
The Oriental Telephone Company opened exchanges in Calcutta, Bombay and Madras. The Central Exchange in Calcutta had 93 subscribers.
Why it mattered. The telephone reached India just six years after Bell's patent.
1913
The summer capital of British India got the country's first automatic exchange, with a capacity of 700 lines and about 400 working connections.
Why it mattered. Automatic switching arrived in India only two decades after La Porte.
1960
Subscriber trunk dialling, STD, let callers dial another city themselves instead of booking a 'trunk call' through an operator. India's first STD route linked Lucknow and Kanpur.
Why it mattered. It was the first step from waiting hours for a trunk call to dialling any city at once.
1984
25 August 1984
The Centre for Development of Telematics was set up to design digital exchanges for Indian conditions: small, rugged rural exchanges (RAX) that could work in heat and dust without air conditioning, and larger ones for cities. Indian firms were licensed to make them.
Why it mattered. It put automatic telephones within reach of small towns and villages across India.
1987
late 1980s – 1990s
Yellow STD/ISD/PCO booths spread to street corners, shops and villages, often run by young entrepreneurs and people with disabilities. For the first time, millions of people without a home phone could dial any city, or any country, themselves. Mobile phones made them rare by the 2010s.
Why it mattered. Public phones brought long-distance calling to ordinary people and created many small businesses.
By the numbers
India's telephone count grew slowly for decades, then faster once STD and home-built exchanges arrived.
1891 – 1970
Strowger's stepping switch, the rotary dial, crossbar grids and touch-tone let callers connect themselves.
1891
10 March 1891
Almon Strowger, an undertaker, patented an automatic stepping switch. The story goes that he believed a local operator was sending his customers' calls to a rival. In his switch, electrical pulses from the caller move a wiper up and round to the right line.
Why it mattered. It began the end of manual switchboards: the exchange could now count the number itself.
1892
3 November 1892
The first commercial automatic exchange, using Strowger's switch, opened in La Porte. Early callers pressed buttons to send the pulses; the finger-wheel rotary dial followed over the next years.
Why it mattered. A small town showed that a phone network could run without operators.
1905
c. 1896–1907
Engineers working with Strowger's company developed the rotary dial, which breaks the line current once for each step as a spring turns it back. By about 1907 the familiar finger-wheel dial with a finger stop had arrived.
Why it mattered. The rotary dial made the caller the operator, one pulse at a time.
1926
1926 (Sweden), 1938 (USA)
Crossbar switches store the dialled number first, then close a single crosspoint in a grid of horizontal and vertical bars. Sweden used Betulander's design from 1926; the US No. 1 crossbar entered service in 1938.
Why it mattered. Crossbar was faster and more reliable than step-by-step, and ran many networks until the digital age.
1963
18 November 1963
The Bell System offered push-button 'Touch-Tone' phones to the public. Each key sends two tones at once, one for its row and one for its column. The same tones still work when a helpline says 'press 1'.
Why it mattered. Dialling became faster, and the keypad became a way to talk to machines.
1915 – 1990
Amplifiers, radio, undersea cables and satellites stretch calls across continents and oceans.
1915
25 January 1915
Bell, in New York, spoke to his old assistant Watson in San Francisco, about 5,500 km away. Vacuum-tube amplifiers along the line kept the voice loud enough to hear.
Why it mattered. Amplifiers meant distance no longer killed the voice.
1927
7 January 1927
The first commercial telephone service between North America and Europe opened, carried by radio. A three-minute call cost about 75 US dollars at the time.
Why it mattered. For the first time, voices crossed an ocean the same day, not weeks later by ship.
1956
25 September 1956
TAT-1 carried 35 telephone calls at once across the Atlantic, with 51 amplifiers, called repeaters, sealed along the sea bed. In its first 24 hours it carried 588 calls between London and the US.
Why it mattered. Undersea cables made international calls clear and common; their fibre successors carry the internet today.
1962
10 July 1962
The Telstar 1 satellite relayed the first live television pictures and telephone calls across the Atlantic. Later satellites were parked in geostationary orbit, 35,786 km up, which adds about a quarter of a second each way.
Why it mattered. Satellites connected places cables could not reach, but their delay made chatting awkward.
1988
14 December 1988
TAT-8, the first transatlantic fibre-optic cable, carried calls as flashes of light, with about 40,000 circuits by most accounts. Fibre soon replaced copper and satellites on the world's busiest routes.
Why it mattered. Glass fibre gave calls, and then the internet, almost unlimited room.
1937 – today
Voices become numbers, exchanges become computers, and calls travel as packets over fibre.
1937
1937–1938
The British engineer Alec Reeves, working for an ITT company in France, invented pulse-code modulation: measuring a sound wave thousands of times a second and sending each measurement as a number. It was too early for the electronics of the day.
Why it mattered. Every digital phone call, and much of today's audio, still uses his idea.
1965
May 1965
The No. 1 Electronic Switching System was the first big exchange controlled by a stored program, like a computer. New services could be added by changing software instead of rewiring.
Why it mattered. Exchanges became computers, which made features like call waiting and call forwarding possible.
1972
The E10 system, developed from research at Lannion, became the first fully digital local exchange to serve customers. Voices were switched as streams of numbers in time slots.
Why it mattered. Digital switching made exchanges smaller, cheaper and far more reliable.
1995
February 1995
VocalTec released InternetPhone, one of the first programs to carry voice calls over the internet (VoIP). Services like Skype (2003) and today's fibre home phones grew from the same idea.
Why it mattered. Your voice became data, sharing the same network as web pages and videos.
2019
19 February 2019
India launched the Emergency Response Support System with a single emergency number, 112, for police, fire, ambulance and more, as used across Europe.
Why it mattered. One easy number, from any phone, can save lives.
2023
Fixed telephone lines fell from 20 per 100 people in 2005 to 11 per 100 in 2023, about 861 million lines, as mobiles took over. Many remaining lines now run over fibre rather than copper.
Why it mattered. The landline is fading, but the ideas inside it, from dialling to digital voice, live on in every mobile call.
Did you know?
A 0 on a rotary dial sends ten pulses and takes a full second to dial.
Calcutta's first telephone exchange, in 1882, had just 93 subscribers.
TAT-1, the first transatlantic telephone cable, carried 588 calls between London and the US in its first 24 hours.
The touch-tone keypad has a secret fourth column, A, B, C and D, which home phones almost never showed.
Almon Strowger, who automated the telephone exchange, was an undertaker.
The people
1808 – 1889 · Inventor · Italy and USA
Built a talking telegraph, the telettrofono, but could not afford a full patent.
1834 – 1874 · Teacher and inventor · Germany
Sent tones, and perhaps a few words, by wire and named the device the Telephon.
1835 – 1901 · Electrical engineer · USA
Filed a caveat for a telephone on the same day as Bell's patent application.
1847 – 1922 · Inventor and teacher of the deaf · Scotland, USA and Canada
Won the telephone patent in 1876 and made the first calls.
1847 – 1931 · Inventor · USA
Patented a carbon transmitter that made telephone calls loud and clear.
1831 – 1900 · Inventor and music professor · Wales, UK and USA
Demonstrated the carbon microphone and gave it its name.
1836 – 1915 · Telegraph engineer · USA
Built the first commercial telephone exchange in New Haven.
1860 – 1915 · Telephone operator · USA
The first woman telephone operator, hired in Boston in 1878.
1839 – 1902 · Undertaker and inventor · USA
Patented the automatic stepping switch that replaced operators.
1902 – 1971 · Engineer · England
Invented pulse-code modulation, the basis of digital telephony.
1942 – · Engineer and entrepreneur · India and USA
Set up C-DOT to build Indian digital exchanges and spread telephones across India.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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