The Telecommunication Portal
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electrical or electronic means, typically through cables, radio waves, or other communication technologies. These means of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent communication sessions. Long-distance technologies invented during the 19th, 20th and 21st centuries generally use electric power, and include the electrical telegraph, telephone, television, and radio.
Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi, who won the 1909 Nobel Prize in Physics. Other early pioneers in electrical and electronic telecommunications include co-inventors of the telegraph Charles Wheatstone and Samuel Morse, numerous inventors and developers of the telephone including Antonio Meucci, Philipp Reis, Elisha Gray and Alexander Graham Bell, inventors of radio Edwin Armstrong and Lee de Forest, as well as inventors of television like Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth.
Since the 1960s, the proliferation of digital technologies has meant that voice communications have gradually been supplemented by data. The physical limitations of metallic media prompted the development of optical fibre. The Internet, a technology independent of any given medium, has provided global access to services for individual users and further reduced location and time limitations on communications. (Full article...)
Selected article -
Morse code is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs. It is named after Samuel Morse, one of several developers of the system. Morse's preliminary proposal for a telegraph code was replaced by an alphabet-based code developed by Alfred Vail, the engineer working with Morse. Vail's version was used for commercial telegraphy in North America. Friedrich Gerke simplified Vail's code to produce the code adopted in Europe, and most of the alphabetic part of the (ITU) "Morse" is copied from Gerke's revision.
The ITU International Morse code encodes the 26 basic Latin letters A to Z, one accented Latin letter É, the Indo-Arabic numerals 0 to 9, and some punctuation and messaging procedural signals (prosigns). There is no distinction between upper and lower case letters. Each code symbol is formed by a sequence of dits and dahs. The dit duration can vary for signal clarity and operator skill, but for any one message, once the rhythm is established, a half-beat is the basic unit of time measurement. The duration of a dah is three times the duration of a dit. Each dit or dah within an encoded character is followed by a period of signal absence, called a space, equal to the dit duration. The letters of a word are separated by a space of duration equal to three dits, and words are separated by a space equal to seven dits. (Full article...)
General images
Naomi ("Joan") Melwit and Norman Banks at the 3KZ microphone, in the late 1930s (from History of broadcasting)
Apple iPhone smartphone (from History of the telephone)
The "Kerbango Internet Radio" was the first stand-alone product that let users listen to Internet radio without a computer. (from History of broadcasting)
Antonio Meucci, 1849, developing a voice-communication apparatus that several sources credit as the first telephone. (from History of the telephone)
The first mass-produced Czechoslovak TV-set Tesla 4001A (1953–57) (from History of television)
Reginald Fessenden, the "father" of radio broadcasting in the U.S. (from History of broadcasting)
AT&T Picturephone (Mod II) fully enclosed in its housing, control pad at bottom (from History of videotelephony)
British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
Early pioneers of radio science and technology in the United States, including Charles Steinmetz, David Sarnoff, Irving Langmuir, and Alfred Goldsmith in 1921, photographed next to the antenna feed wires of the New Brunswick Marconi Station, one of the first transatlantic radio links. The photo includes Albert Einstein as a visiting guest. (from History of radio)
Replica of the telettrofono at Museo Nazionale Scienza e Tecnologia Leonardo da Vinci of Milan, Italy, invented by Antonio Meucci and credited by several sources as the first telephone. (from History of the telephone)
Thomas Edison invented the carbon microphone which produced a strong telephone signal. (from History of the telephone)
Artist's conception: 21st-century videotelephony imagined in the early 20th century (1910) (from History of videotelephony)
John Logie Baird in 1925 with his televisor equipment and dummies "James" and "Stooky Bill" (right) (from History of television)
The Marconi Company was formed in England in 1910. The photo shows a typical early scene, from 1906, with Marconi employee Donald Manson at right. (from History of broadcasting)
DBS satellite dishes (from History of television)
Color bars used in a test pattern, sometimes used when no program material is available (from History of television)
A replica of one of Claude Chappe's semaphore towers (optical telegraph) in Nalbach, Germany (from History of telecommunication)
Charles Logwood broadcasting at New York station 2XG, 1916 (from History of broadcasting)
- Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris (from History of the telephone)
Bell prototype telephone stamp(from History of the telephone)
Centennial Issue of 1976
1896 telephone (Sweden) (from History of the telephone)
"Doc" Herrold is shown at the microphone of KQW, c. 1925 (from History of broadcasting)
Reis's telephone around 1861, first device called telephone (from History of the telephone)
Australian radio sets usually had the positions of radio stations marked on their dials. The illustration is a dial from a transistorised, mains-operated Calstan radio, c. 1960s. (Click image for a high resolution view, with readable callsigns.) (from History of broadcasting)
The Kyocera VP-210 Visual Phone was the first commercial mobile videophone. The Personal Handy-phone System (PHS) phone was introduced in Japan (1999). (from History of videotelephony)
A 19th century acoustic tin can or "lovers' telephone" (from History of the telephone)
Screen idol Rudolph Valentino at the microphone of WSB in Atlanta, 1923 (from History of broadcasting)
Guglielmo Marconi (from History of broadcasting)
Philo Farnsworth in 1924 (from History of television)
Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation. (from History of radio)
The French Matra videophone (1970) (from History of videotelephony)
The Philco Predicta, 1958. In the collection of The Children's Museum of Indianapolis (from History of television)
The first commercial AM Audion vacuum tube radio transmitter, built in 1914 by Lee De Forest who invented the Audion (triode) in 1906 (from History of radio)
AT&T magazine advertisement announcing commercial launch of Picturephone service. (from History of videotelephony)
1917 wall telephone, open to show magneto and local battery (from History of the telephone)
An early experiment demonstrating the refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio)
Swedish Prime Minister Tage Erlander using an Ericsson videophone to speak with Lennart Hyland, a popular TV show host (1969) (from History of videotelephony)
The master telephone patent, 174465, granted to Bell, March 7, 1876 (from History of telecommunication)
Ad for the beginning of experimental television broadcasting in New York City by RCA in 1939 (from History of television)
RCA 630-TS, the first mass-produced television set, which sold in 1946–1947 (from History of television)
Manfred von Ardenne in 1933 (from History of television)
Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. (from History of the telephone)
Typical low-cost webcam used with many personal computers (from History of videotelephony)
Top of cellular telephone tower (from History of the telephone)
The Nipkow disk. This schematic shows the circular paths traced by the holes, which may also be square for greater precision. The area of the disk outlined in black shows the region scanned. (from History of television)
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Selected biography -
Guglielmo Giovanni Maria Marconi, 1st Marquess of Marconi (25 April 1874 – 20 July 1937), was an Italian electrical engineer, inventor, and politician known for his creation of a practical radio wave-based wireless telegraph system. This led to his being largely credited as the inventor of radio and sharing the 1909 Nobel Prize in Physics with Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy."
As an entrepreneur and a businessman, Marconi founded The Wireless Telegraph & Signal Company (later the Marconi Company) in the United Kingdom in 1897. In 1929, he was ennobled as a marquess (Italian: marchese) by King Victor Emmanuel III, thus becoming the 1st Marchese di Marconi. In 1931, he set up Vatican Radio for Pope Pius XI. (Full article...)
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