Almon Strowger

From Academic Kids

Almon Brown Strowger (1839May 26, 1902) gave his name to the electromechanical telephone exchange technology that his invention and patent inspired.


Early years

He was born in Penfield, near Rochester, New York. Little information is available about his early life. He is understood to be an American Civil War veteran as his grave is marked with the traditional white headstone with an inscription that reads:

Lieut. A.B. Strowger, Co. A, 8 NY Cav.

It is believed that he fought in the Second Battle of Bull Run near Manassas, Virginia.

After the Civil War, it appears he first became a country school teacher before he became an undertaker. He is variously attributed as living in El Dorado, Kansas or Topeka, Kansas, and finally Kansas City, Missouri. It is not clear where his idea of an automatic telephone exchange was originally conceived, but his patent application identifies him as being a resident of Kansas City, Missouri on March 10, 1891.

He is commonly identified as a Kansas City undertaker, (or occasionally as either a funeral parlor director or a mortician), who invented the automatic telephone exchange and has been described as the father of the automatic telephone exchange. Strowger himself would more likely have characterised his invention as the "girl-less, cuss-less" telephone system.

He was apparently motivated to invent an automatic telephone exchange after having difficulties with the local telephone operators. He was convinced that the local manual telephone exchange operators were sending calls to his competitor rather than his business. He also suspected that the telephone operators were influencing the choice of undertaker when his business was requested. The origin of this suspicion reportedly arose from an incident in Topeka when a friend died and the family contacted a rival undertaker. Other stories claim that the wife or, possibly, the cousin of a rival was a telephone operator and Strowger suspected that the operators were telling callers that his line was busy or connecting his callers to the competition. The full story is now clouded by the passage of time, though historians report that those who knew him have described him as "eccentric, irascible and even mad".

Later years

Convinced that subscribers should choose who was called, rather than the operator, he first conceived his invention in 1888, and patented the automatic telephone exchange in 1891. It is reported that he initially constructed a model of his invention from a round collar box and some straight pins.

So what was so revolutionary about his invention that so many others had failed to devise previously? The patent consists of:

  1. A device for use by customer - this creates trains of on-off current pulses corresponding to the digits 0-9 (this evolved into the rotary dial telephone)
  2. A 2 motion stepping switch at telephone exchange. Rotating arm steps over, in a semi-circular fashion, 10 possible contact points. The stepping motion was controlled by the current pulses coming from the originating customer's dialing device.
  3. Cascading enabled connection among more than 10 customers. Switching devices can also be positioned in the vertical direction as well as horizontal direction, also increasing the switching capacity.
  • The addition of a line finder selector to reduce the number of switches needed, and circuits to detect busy connections were made in later designs. But these were minor enhancements to the fundamental concept.

It is the fundamental modularity of the system combined with its step-by-step (hence the alternative name) selection process and an almost unlimited potential for expansion that gives the Strowger system its technical advantage: previous systems had all been designed for a fixed number of subscribers to be switched directly to each other in a mesh arrangement. This became orders of magnitude more complex as each new customer was added, as each new customer needed a switch to connect to every other customer. In modern terminology, the previous systems were simply not scalable.

While he may have come up with the idea, he was not alone in his endeavours and sought the assistance of his nephew William and others with a knowledge of electricity and money to realise his concepts. With this help the Strowger Automatic Telephone Exchange Company was formed and it installed and opened the first commercial exchange in (his then home town of) La Porte, Indiana on November 3, 1892, with about 75 subscribers and capacity for 99.

The company's engineers continued development of Strowger's designs and submitted several patents in the names of its employees. It also underwent several name changes. Strowger himself seems to have not taken part in this further development. He subsequently moved to St. Petersburg, Pinellas County, Florida and appears to have returned to being an undertaker, as H.P. Bussey Funeral Home records report an unidentified body being moved "for Mr. Strowger" in December 1899. The same funeral home subsequently buried Strowger himself. Strowger was a man of some wealth at his death and was reported as owning at least a city block of property.

Death and afterwards

He died, aged 62, of an aneurism after suffering from anemia, at St. Petersburg, Pinellas County, Florida and was buried in Greenwood Cemetery ( the next day.

He was survived by his widow Susan A. Strowger (1846 - 1921). After her death in Tampa, Florida, on April 14, 1921, her obituary appeared in the St. Petersburg Times, claiming she had additional "revolutionary" Strowger designs, but she had refused to make them public while she was alive because only others would profit from her husband's designs. She had claimed that her husband had only received $10,000 for his invention, when he should have received a million.

Strowger sold his patents in 1896 for $1,800 and sold his share in the Automatic Electric Company for $10,000 in 1898. His patents subsequently sold for $2.5 Million in 1916.

A bronze plaque, to commemorate his invention, was placed on his grave in 1945 by telephone company officials. Strowger was admitted to the hall of fame of the U.S. Independent Telephone Association in 1965. Apart from his invention, his name has also been given to a locomotive and a company business award.

In 2003, the Verizon Foundation awarded $4500 to Pinellas Heritage, Inc. and the Pinellas Genealogy Society in Strowger's memory. The funds were used to develop a website to impart the history of the cemetery where Strowger is buried, and to restore two Civil War memorials. The Greenwood Cemetery project won an organization achievement award from the Florida Trust for Historic Preservation.


  • Strowger was quoted as saying: "No longer will my competitor steal all my business just because his wife is a BELL operator."


  • Template:US patent -- Strowger switch -- "Automatic Telephone Exchange" -- March 10, 1891

See also


  1. R.B.Hill, "Early Work on Dial Telephone Systems" January, 1953 Bell Laboratories Record. (Volume XXXI No. 1, January, 1953. P. 22 et. seq.)
  2. R.B.Hill, "The Early Years of the Strowger System" March, 1953 Bell Laboratories Record. (Volume XXXI No. 3, March, 1953. P. 95 et. seq.)

External links


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