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Invention Of The Telephone
The invention of the telephone was the culmination of work done by more than one individual, and led to an array of lawsuits relating to the patent claims of several individuals and numerous companies. Early development The concept of the telephone dates back to the string telephone or lover's telephone that has been known for centuries, comprising two diaphragms connected by a taut string or wire. Sound waves are carried as mechanical vibrations along the string or wire from one diaphragm to the other. The classic example is the tin can telephone, a children's toy made by connecting the two ends of a string to the bottoms of two metal cans, paper cups or similar items. The essential idea of this toy was that a diaphragm can collect voice sounds from the voice sounds for reproduction at a distance. One precursor to the development of the electromagnetic telephone originated in 1833 when Carl Friedrich Gauss and Wilhelm Eduard Weber invented an electromagnetic device for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidetone
Sidetone is audible feedback to someone speaking or otherwise producing sound as an indication of active transmission. Sidetone is introduced by some communications circuits and anti-sidetone circuitry is used to control its level. Sidetone is expected behavior for telephone systems. Absence of sidetone can cause users to believe the call has been dropped or cause them to speak loudly. Too much sidetone can cause users to speak softly. Telephony In telephony, sidetone is the effect of sound picked up by the telephone's transmitter (mouthpiece) and instantly introduced at a low electronic signal level into the receiver (earpiece) of the same handset, a form of electrical feedback through the telephone hybrid.AT&T, ''Bell System Practices'', Section C30.001 Issue 1 (March 16, 1932) ''Common Battery Anti-Sidetone Stations'' Sidetone in early 19th century telephones was strong due to the type of circuit used in instruments. Anti-sidetone circuitry in the telephone hybrid brought sideto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it is the oldest continuously published magazine in the United States. ''Scientific American'' is owned by Springer Nature, which in turn is a subsidiary of Holtzbrinck Publishing Group. History ''Scientific American'' was founded by inventor and publisher Rufus Porter in 1845 as a four-page weekly newspaper. The first issue of the large format newspaper was released August 28, 1845. Throughout its early years, much emphasis was placed on reports of what was going on at the U.S. Patent Office. It also reported on a broad range of inventions including perpetual motion machines, an 1860 device for buoying vessels by Abraham Lincoln, and the universal joint which now can be found in nearly every automobile manufactured. Current issues includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litz Wire
Litz wire is a particular type of multistrand wire or cable used in electronics to carry alternating current (AC) at radio frequencies. The wire is designed to reduce the skin effect and proximity effect losses in conductors used at frequencies up to about 1 MHz. It consists of many thin wire strands, individually insulated and twisted or woven together, following one of several carefully prescribed patterns often involving several levels (groups of twisted wires are twisted together, etc.). The result of these winding patterns is to equalize the proportion of the overall length over which each strand is at the outside of the conductor. This has the effect of distributing the current equally among the wire strands, reducing the resistance. Litz wire is used in high Q inductors for radio transmitters and receivers operating at low frequencies, induction heating equipment and switching power supplies. The term litz wire originates from ''Litzendraht'' (coll. ''Litze' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patient
A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health care provider. Etymology The word patient originally meant 'one who suffers'. This English noun comes from the Latin word ', the present participle of the deponent verb, ', meaning 'I am suffering,' and akin to the Greek verb (', to suffer) and its cognate noun (). This language has been construed as meaning that the role of patients is to passively accept and tolerate the suffering and treatments prescribed by the healthcare providers, without engaging in shared decision-making about their care. Outpatients and inpatients An outpatient (or out-patient) is a patient who attends an outpatient clinic with no plan to stay beyond the duration of the visit. Even if the patient will not be formally admitted with a note as an out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philipp Reis
Johann Philipp Reis (; 7 January 1834 – 14 January 1874) was a self-taught German scientist and inventor. In 1861, he constructed the first ''make-and-break'' telephone, today called the Reis telephone. Early life and education Reis was born in Gelnhausen, Germany, the son of Marie Katharine (Glöckner) and Karl Sigismund Reis, a master baker. His father belonged to the Evangelical Lutheran church. Reis's mother died while he was an infant, and he was raised by his paternal grandmother, a well-read, intelligent woman. At the age of six Reis was sent to the common school of his home town of Gelnhausen. Here his talents attracted the notice of his instructors, who advised his father to extend his education at a higher college. His father died before Reis was ten years old. His grandmother and guardians placed him at Garnier's Institute, in Friedrichsdorf, where he showed a taste for languages, and acquired both French and English, as well as a stock of miscellaneous inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheumatism
Rheumatism or rheumatic disorders are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. Rheumatism does not designate any specific disorder, but covers at least 200 different conditions, including arthritis and "non-articular rheumatism", also known as "regional pain syndrome" or "soft tissue rheumatism". There is a close overlap between the term soft tissue disorder and rheumatism. Sometimes the term "soft tissue rheumatic disorders" is used to describe these conditions. The term "Rheumatic Diseases" is used in MeSH to refer to connective tissue disorders. The branch of medicine devoted to the diagnosis and therapy of rheumatism is called rheumatology. Types Many rheumatic disorders of chronic, intermittent pain (including joint pain, neck pain or back pain) have historically been caused by infectious diseases. Their etiology was unknown until the 20th century and not treatable. Postinfectious arthritis, also known as reactive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CSELT
Centro Studi e Laboratori Telecomunicazioni (CSELT) was an Italian research center for telecommunication based in Torino, the biggest in Italy and one of the most important in Europe. It played a major role internationally especially in the standardization of protocols and technologies in telecommunication: perhaps the most widely well known is the standardization of mp3. CSELT has been active from 1964 to 2001, initially as a part of the Istituto per la Ricostruzione Industriale- STET – Società Finanziaria Telefonica group, the major conglomerate of Italian public Industries in the 1960s and 1970s; it later became part of Telecom Italia Group. In 2001 was renamed TILAB as part of Telecom Italia Group. Research areas Transmission technology and fiber optics CSELT became internationally known at the end of 1960s thanks to a cooperation with the US-based company COMSAT for a pilot project of TDMA (and PCM) satellite communication system. Furthermore, in 1971 it started a jo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecom Italia
Gruppo TIM, legally TIM S.p.A. (formerly Telecom Italia S.p.A.), also known as the TIM Group in English, is an Italian telecommunications company with headquarters in Rome, Milan, and Naples, (with the Telecom Italia Tower) which provides fixed telephony and DSL data services. It is the largest Italian telecommunications services provider in revenues and subscribers. It was founded in 1994 by the merger of several state-owned telecommunications companies, the most prominent of which was Società Italiana per l'Esercizio Telefonico p.A., (known as ''SIP''), the former state monopoly telephone operator in Italy. The company's stock is traded in the Borsa Italiana. Since 2017, the Italian State exercises on TIM the "Golden Power", which allows the government to take a number of actions when the strategic interests of the country are concerned. History 1925–1964: Stipel and early mandatory phone tax In 1925, the phone network was reorganised by the Benito Mussolini cabinet a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Graham Bell
Alexander Graham Bell (, born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and Telegraph Company (AT&T) in 1885. Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf; profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being awarded the first U.S. patent for the telephone, on March 7, 1876. Bell considered his invention an intrusion on his real work as a scientist and refused to have a telephone in his study. Many other inventions marked Bell's later life, including groundbreaking work in optical telecommunications, hydrofoils, and aeronautics. Bell also had a strong influence on the National Geographic Society and it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
