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Telephone
March 1876 (Bell; Gray and Meucci claims)· Invention or discovery· Communication & computing
DebatedHistorians or scientists disagree about what happened, when, or why.
A device that turns the voice into a varying electric current and back into sound, patented by Alexander Graham Bell in 1876.
See it on the Technology & Medicine map →How it works
A telephone's transmitter turns sound waves into a matching electric signal; at the other end, a thin iron diaphragm moved by an electromagnet turns it back into sound. Bell, a Scottish-born teacher of the deaf in Boston, filed his patent on February 14, 1876, the same day Elisha Gray filed a caveat (a notice of intent) for a similar design. On March 10 Bell spoke the first words: 'Mr. Watson, come here.' Carbon transmitters, from Edison and others, soon made voices clearer.
Why it mattered
The phone let anyone talk in real time across distance, without an operator who knew code. It reshaped business and spawned Bell Labs, a powerhouse of 20th-century invention.
How we know
Bell's US patent 174,465, granted March 7, 1876; his notebook entry for March 10; records of some 600 patent lawsuits, with Bell's patent upheld by the US Supreme Court in 1888.
Still unknown or debated
Whether Bell saw Gray's caveat before finishing his design is disputed. Antonio Meucci built voice devices in the 1850s; a 2002 US House resolution honored his work.
Connections (3)
▸Electric telegraph led to the TelephoneWell documented
The connection
The telegraph was the big market, and inventors including Bell and Gray were trying to send several messages at once on one wire using different tones, a 'harmonic telegraph'. Working on that, Bell realized a wire could carry the full shape of a voice. Early phone networks reused telegraph-style wires, poles and switchboards.
When and how
Boston, 1874–76, Bell with assistant Thomas Watson; Chicago, Elisha Gray, co-founder of the telegraph-equipment maker Western Electric.
How we know
Bell's notebooks and patent grew out of his harmonic telegraph work; telegraph giant Western Union entered the phone business with Gray's and Edison's designs, then settled with Bell in 1879.
Debates and open questions
The story that Western Union turned down Bell's patent for $100,000 is often retold, but the evidence for it is thin.
▸Telephone went wireless as the Mobile phoneWell documented
The connection
Bell's telephone turned the voice into an electrical current sent down a wire. A mobile phone sends the same voice signal by radio to a nearby tower, which passes it into the ordinary phone network. Cooper's first 1973 call went to a desk phone at Bell Labs, Motorola's chief rival.
When and how
Bell in Boston, 1876; Martin Cooper of Motorola on Sixth Avenue in New York, April 3, 1973; first commercial cellular network in Tokyo, 1979.
How we know
Mobile phones were built to plug into the existing telephone network and share its numbering system; Motorola and AT&T records document the work.
Debates and open questions
Why US cellular service took until 1983 is debated: slow FCC decisions on radio channels, AT&T's phone monopoly and costly handsets are all blamed.
▸Telephone paid for the Bell Labs research behind the TransistorMostly agreed
The connection
AT&T's Bell System, the US telephone monopoly, funded Bell Labs, among the world's richest research centers. It wanted something better than the vacuum tubes that amplified long-distance calls and the mechanical relays that switched them, since tubes ran hot and burned out. That goal led directly to the 1947 transistor.
When and how
Bell Labs, Murray Hill, New Jersey; research director Mervin Kelly set up a solid-state physics group under William Shockley in 1945.
How sure are we?
Bell Labs memos and Kelly's stated aims are well documented; AT&T licensed the transistor patent widely from 1952, partly under antitrust pressure.
Debates and open questions
Economists debate whether monopoly profits are needed to fund such basic research, or whether Bell Labs was a one-off of its era.