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Almon StrowgerAlmon Strowger


Almon Strowger was born in Penfield, New York, on September 5, 1829. One of seven brothers, it was said that Almon was always good at inventing machines to do his and his brothers' chores, and that ability would serve him well in his later life. At the age of 22, he enlisted in the New York Cavalry, and he subsequently served in the Union Army during the Civil War. Sometime after the war he moved to Kansas, where he taught school in either El Dorado or Topeka. By 1891 he was the owner of an undertaking business in Kansas City, Missouri, and it was while so engaged that he invented the automatic telephone switching system.

There are many different stories of how Strowger came up with the invention that made him famous, but the most commonly repeated one says that he became frustrated over human operators misdirecting calls from his customers, and that he was certain the misdirects were intentional. Believing it necessary, therefore, to get rid of the human element in placing calls, Strowger is said to have used a round cardboard collar box and a hundred straight pins to lay out his basic concept. What he came up with was a system of buttons and electromagnets. Each time the caller tapped a button a signal was sent to a central switchboard, where an electromagnetic "pointer" moved the caller's line until it was in contact with the desired number. The process was repeated for each individual number within the telephone number until the full connection was made. Strowger received Patent Number 447,918 on March 10, 1891, and incorporated Strowger Automatic Telephone Exchange that same year. The first automatic telephone exchange was installed in La Porte, Indiana, in 1892.

Strowger's original automatic telephone exchange

Strowger's original concept could only handle 99 telephones, used buttons that required several pushes to complete the proper connection, and required a strong battery and five wires to connect to the central office. Although it was somewhat cumbersome and difficult to use, the general public accepted it readily. He improved his design over the ensuing years, and, in 1896, he patented the dial telephone.

Strowger sold his patents to his associates in 1896 and moved to St. Petersburg, Florida, where he resumed his undertaking business. He died there on March 14, 1908.

Although many improvements were made over the years, Strowger's automatic telephone exchange remained the standard of the industry around the world until the invention of touch-tone dialing in the late 1970's. And, even though many of the individual components have changed over the years, the inner workings of today's telephone exchange systems still bear a strong resemblance to the design first created by Strowger in 1891. He was inducted into the National Inventors Hall of Fame in 2006.

a modern version of Strowger's automatic telephone exchange device

Civil War

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This page was last updated on 01/15/2015.

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