An electrical telegraph is a telegraph that uses coded electrical signals to convey information via dedicated electrical wiring. Electrical telegraphy dates from the early 1800s, is distinct from the electrical telephony, which uses the analogue magnitude of electrical signals to convey information; the electrical telegraph, or more just telegraph, superseded optical semaphore telegraph systems, thus becoming the first form of electrical telecommunications. In a matter of decades after their creation in the 1830s, electrical telegraph networks permitted people and commerce to transmit messages across both continents and oceans instantly, with widespread social and economic impacts. From early studies of electricity, electrical phenomena were known to travel with great speed, many experimenters worked on the application of electricity to communications at a distance. All the known effects of electricity - such as sparks, electrostatic attraction, chemical changes, electric shocks, electromagnetism - were applied to the problems of detecting controlled transmissions of electricity at various distances.
In 1753, an anonymous writer in the Scots Magazine suggested an electrostatic telegraph. Using one wire for each letter of the alphabet, a message could be transmitted by connecting the wire terminals in turn to an electrostatic machine, observing the deflection of pith balls at the far end. Telegraphs employing electrostatic attraction were the basis of early experiments in electrical telegraphy in Europe, but were abandoned as being impractical and were never developed into a useful communication system. In 1774, Georges-Louis Le Sage realised an early electric telegraph; the telegraph had a separate wire for each of the 26 letters of the alphabet and its range was only between two rooms of his home. In 1800, Alessandro Volta invented the voltaic pile, allowing for a continuous current of electricity for experimentation; this became a source of a low-voltage current that could be used to produce more distinct effects, and, far less limited than the momentary discharge of an electrostatic machine, which with Leyden jars were the only known man-made sources of electricity.
Another early experiment in electrical telegraphy was an'electrochemical telegraph' created by the German physician and inventor Samuel Thomas von Sömmering in 1809, based on an earlier, less robust design of 1804 by Spanish polymath and scientist Francisco Salva Campillo. Both their designs employed multiple wires to represent all Latin letters and numerals. Thus, messages could be conveyed electrically up to a few kilometers, with each of the telegraph receiver's wires immersed in a separate glass tube of acid. An electric current was sequentially applied by the sender through the various wires representing each digit of a message; the telegraph receiver's operator would watch the bubbles and could record the transmitted message. This is in contrast to telegraphs that used a single wire. Hans Christian Ørsted discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle. In the same year Johann Schweigger invented the galvanometer, with a coil of wire around a compass, which could be used as a sensitive indicator for an electric current.
In 1821, André-Marie Ampère suggested that telegraphy could be done by a system of galvanometers, with one wire per galvanometer to indicate each letter, said he had experimented with such a system. In 1824, Peter Barlow said that such a system only worked to a distance of about 200 feet, so was impractical. In 1825, William Sturgeon invented the electromagnet, with a single winding of uninsulated wire on a piece of varnished iron, which increased the magnetic force produced by electric current. Joseph Henry improved it in 1828 by placing several windings of insulated wire around the bar, creating a much more powerful electromagnet which could operate a telegraph through the high resistance of long telegraph wires. During his tenure at The Albany Academy from 1826 to 1832, Henry first demonstrated the theory of the'magnetic telegraph' by ringing a bell through a mile of wire strung around the room. In 1835, Joseph Henry and Edward Davy invented the critical electrical relay. Davy's relay used a magnetic needle which dipped into a mercury contact when an electric current passed through the surrounding coil.
Davy demonstrated his telegraph system in Regent's Park in 1837 and was granted a patent on 4 July 1838. Davy invented a printing telegraph which used the electric current from the telegraph signal to mark a ribbon of calico impregnated with potassium iodide and calcium hypochlorite; the first working telegraph was built by the English inventor Francis Ronalds in 1816 and used static electricity. At the family home on Hammersmith Mall, he set up a complete subterranean system in a 175 yard long trench as well as an eight mile long overhead telegraph; the lines were connected at both ends to revolving dials marked with the letters of the alphabet and electrical impulses sent along the wire were used to transmit messages. Offering his invention to the Admiralty in July 1816, it was rejected as "wholly unnecessary", his account of the scheme and the possibilities of rapid global communication in Descriptions of an Electrical Telegraph and of some other Electrical Apparatus was the first published work on electric telegraphy and described the risk of signal retardation due to induction.
Elements of Ronalds’ design were utilised in the subsequent commercialisation of the telegraph over 2
Transylvania is a historical region, located in central Romania. Bound on the east and south by its natural borders, the Carpathian mountain range, historical Transylvania extended westward to the Apuseni Mountains; the term sometimes encompasses not only Transylvania proper, but parts of the historical regions of Crișana and Maramureș, the Romanian part of Banat. The region of Transylvania is known for the scenery of its Carpathian landscape and its rich history, it contains major cities such as Cluj-Napoca, Brașov, Sibiu, Târgu Mureș, Bistrița. The Western world associates Transylvania with vampires, because of the influence of Bram Stoker's novel Dracula and its many film adaptations. Historical names of Transylvania are: Latin: Ultrasilvania, Transsilvania Romanian: Ardeal, Transilvania Russian: Ардял, translit. Ardjal, Трансильвания Transil'vanija Hungarian: Erdély Ukrainian: Семигород, translit. Semyhorod, Залісся Zalissja, Трансильванія Transyl'vanija Serbian: Ердељ, translit. Erdelj, Трансилванија Transilvanija Croatian: Sedmogradska, Transilvanija Bulgarian: Седмоградско, translit.
Sedmogradsko, Трансилвания Transilvanija Slovak: Sedmohradsko German: Siebenbürgen, Transsilvanien Transylvanian Saxon: Siweberjen Polish: Siedmiogród, Transylwania Turkish: Erdel, Transilvanya Romani: TransilvaniyaIn Romanian, the region is known as Ardeal or Transilvania. The earliest known reference to Transylvania appears in a Medieval Latin document in 1075 as ultra silvam, meaning "beyond the forest". Transylvania, with an alternative Latin prepositional prefix, means "on the other side of the woods". Hungarian historians claim that the Medieval Latin form Ultrasylvania Transsylvania, was a direct translation from the Hungarian form Erdő-elve; that was used as an alternative name in German überwald and Ukrainian Залісся. The German name Siebenbürgen means "seven castles", after the seven Transylvanian Saxons' cities in the region; this is the origin of the region's name in many other languages, such as the Croatian Sedmogradska, the Bulgarian Седмиградско, Polish Siedmiogród and the Ukrainian Семигород.
The Hungarian form Erdély was first mentioned in the 12th-century Gesta Hungarorum as Erdeuleu or Erdő-elve. The word Erdő means forest in Hungarian, the word Elve denotes a region in connection with this to the Hungarian name for Muntenia. Erdel, Erdelistan, the Turkish equivalents, or the Romanian Ardeal were borrowed from this form as well; the first known written occurrence of the Romanian name Ardeal appeared in a document in 1432 as Ardeliu. The Romanian Ardeal is derived from the Hungarian Erdély. Transylvania has been dominated by several different countries throughout its history, it was once the nucleus of the Kingdom of Dacia. In 106 AD the Roman Empire conquered the territory. After the Roman legions withdrew in 271 AD, it was overrun by a succession of various tribes, bringing it under the control of the Carpi, Huns, Gepids and Slavs. From 9th to 11th century Bulgarians ruled Transylvania, it is a subject of dispute whether elements of the mixed Daco–Roman population survived in Transylvania through the Post-classical Era or the first Vlachs/Romanians appeared in the area in the 13th century after a northward migration from the Balkan Peninsula.
There is an ongoing scholarly debate over the ethnicity of Transylvania's population before the Hungarian conquest. The Magyars conquered much of Central Europe at the end of the 9th century. According to Gesta Hungarorum, the Vlach voivode Gelou ruled Transylvania before the Hungarians arrived; the Kingdom of Hungary established partial control over Transylvania in 1003, when king Stephen I, according to legend, defeated the prince named Gyula. Some historians assert Transylvania was settled by Hungarians in several stages between the 10th and 13th centuries, while others claim that it was settled, since the earliest Hungarian artifacts found in the region are dated to the first half of the 10th century. Between 1003 and 1526, Transylvania was a voivodeship in the Kingdom of Hungary, led by a voivode appointed by the King of Hungary. After the Battle of Mohács in 1526, Transylvania became part of the Kingdom of János Szapolyai. In 1570, the kingdom transformed into the Principality of Transylvania, ruled by Calvinist Hungarian princes.
During that time, the ethnic composition of Transylvania transformed from an estimated near equal number of the ethnic groups to a Romanian majority. Vasile Lupu estimates their number more than one-third of the population of Transylvania in a letter to the sultan around 1650. For most of this period, maintaining its internal autonomy, was under the suzerainty of the Ottoman Empire; the Habsburgs acquired the territory shortly after the Battle of Vienna in 1683. In 1687, the rulers of Transylvania recognized the suzerainty of the Habsburg emperor Leopold I, the region was attached to the Habsburg Empire; the Habsburgs acknowledged Principality of Transylvania as one of the Lands of the Crown of Saint Stephen, but the territory of principality was administratively separa
Telephone Newspapers, introduced in the 1890s, transmitted news and entertainment to subscribers over telephone lines. They were the first example of electronic broadcasting, although only a few were established, most in European cities; these systems predated the development, of radio broadcasting. They were supplanted by radio stations, because radio signals could more cover much wider areas with higher quality audio, without incurring the costs of a telephone line infrastructure; the introduction of the telephone in the mid-1870s included numerous demonstrations of its use for transmitting musical concerts over various distances. In one advanced example, Clément Ader prepared a listening room at the 1881 Paris Electrical Exhibition, where attendees could listen to performances, in stereo, from the Paris Grand Opera; the concept appeared in Edward Bellamy's influential 1888 utopian novel, Looking Backward: 2000-1887, which foresaw audio entertainment sent over telephone lines to private homes.
The initial scattered demonstrations were followed by the development of more organized services transmitting news and entertainment, which were collectively called "telephone newspapers". However, the technical capabilities of the time — vacuum tube amplification would not become practical until the 1920s — meant that there were limited means for amplifying and relaying telephone signals to multiple sites over long distances, so service areas were limited to a single jurisdiction, in most cases listeners needed to use headphones to hear the programs. During this era telephones were costly, near-luxury items, so subscribers tended to be among the well-to-do. Financing for the systems was done by charging fees, including monthly subscriptions for home users, and, in locations such as hotel lobbies, through the use of coin-operated receivers, which provided short periods of listening for a set payment; some systems accepted paid advertising. While some of the systems, including the Telefon Hírmondó, built their own one-way transmission lines, including the Electrophone, used the existing commercial telephone lines, which allowed subscribers to talk to operators in order to select programs.
Programming originated from the system's own studios, although outside sources were used, including local theaters and church services, where special telephone lines carried the transmissions to the distributing equipment. In two cases, the Telefon Hírmondó and the Araldo Telefonico, the systems were merged with radio station operations, becoming relays for the radio programs. Below is a chronological overview of some of the systems; the first organized telephone-based entertainment service appears to be the Théâtrophone, which went into operation in Paris, France in 1890. This system evolved from Clément Ader's demonstration at the 1881 Paris Electrical Exhibition by Compagnie du Théâtrophone of MM. Marinovitch and Szarvady. Although the service received most of its programming from lines run to local theaters, it included regular five-minute news summaries. Home listeners could connect to the service, with an 1893 report stating that the system had grown to over 1,300 subscribers; the company established coin-operated receivers, in locations such as hotels, charging 50 centimes for five minutes of listening, one franc for twice as long.
By 1925, the system had adopted vacuum tube amplification, which allowed listeners to hear over loudspeakers instead of headphones. The service continued in operation until 1932, when it was found it could no longer compete with radio broadcasting; the Telefon Hírmondó — the name was translated into English as the "Telephone Herald" or "Telephone News-teller" — was created by inventor and telephone engineer Tivadar Puskás. Puskás had participated in Clément Ader's demonstration at the 1881 Paris Electrical Exhibition, he had been an important early developer of the telephone switchboard, he developed the basic technology for transmitting a single audio source to multiple telephones. On February 15, 1893 the Telefon Hírmondó, which would become the most prominent and longest-lived of all the Telephone Newspaper systems, began operating in the Pest section of Budapest; the system offered a wide assortment of news, stock quotations and linguistic lessons. Tivadar Puskás died just one month after the system went into operation, after which his brother assumed responsibility for the system.
The Telefon Hírmondó was classified and regulated by the Hungarian government as a newspaper, with a designated editor-in-chief responsible for content. Both the Italian Araldo Telefonico and the United States Telephone Herald Company licensed the Telefon Hírmondó technology for use in their respective countries; the limited means for signal amplification required that the Telefon Hírmondó employ strong-voiced "stentors" to speak loudly into double-cased telephones, so that they could be heard throughout the system by listeners that used headphones. A loud buzzer, which could be heard throughout a room when the service was not being monitored, was used to draw attention to important transmissions. Service was supplied to private homes as well as commercial establishments, including hotels and doctor's offices. At its peak, the service had thousands of subscribers, many contemporary reviews mentioned that the subscription price was quite reasonable; the Telefon Hírmondó provided a short hourly news program using subscriber's regular phone lines.
This was soon expanded into a continuous service. Its schedul
Bell Telephone Company
The Bell Telephone Company, a common law joint stock company, was organized in Boston, Massachusetts on July 9, 1877, by Alexander Graham Bell's father-in-law Gardiner Greene Hubbard, who helped organize a sister company — the New England Telephone and Telegraph Company. The Bell Telephone Company was started on the basis of holding "potentially valuable patents", principally Bell's master telephone patent #174465; the two companies merged on February 17, 1879, to form two new entities, the National Bell Telephone Company of Boston, the International Bell Telephone Company, soon after established by Hubbard and which became headquartered in Brussels, Belgium. Theodore Vail took over its operations at that point, becoming a central figure in its rapid growth and commercial success; the National Bell Telephone Company merged with American Speaking Telephone Company on March 20, 1880, to form the American Bell Telephone Company of Boston, Massachusetts. Upon its inception, the Bell Telephone Company was organized with Hubbard as "trustee", although he was additionally its de facto president, since he controlled his daughter's shares by power of attorney, with Thomas Sanders, its principal financial backer, as treasurer.
The American Bell Telephone Company evolved into the American Telephone & Telegraph Company, at times the world's largest telephone company. The Bell Patent Association, was not a corporate entity but a partnership, it was established verbally in 1874 to be the holders of the patents produced by Alexander Graham Bell and his assistant Thomas Watson. Approximate one-third interests were at first held by Gardiner Greene Hubbard, a lawyer and Bell's future father-in-law. Hubbard registered some of his shares with two other family members. An approximate 10% interest of the patent association was assigned by its principals to Bell's technical assistant Thomas Watson, in lieu of salary and for his earlier financial support to Bell while they worked together creating their first functional telephones; the verbal patent association agreement was formalized in a memorandum of agreement on February 27, 1875. The patent association's assets became the foundational assets of the Bell Telephone Company. At the time of the organization of the Bell Telephone Company as an association, on July 9, 1877, as a joint stock company in 1877 by Hubbard, who soon became its trustee and de facto president, 5,000 shares in total were issued to: Gardiner Greene Hubbard: 1,397 shares, along with Gertrude McC. Hubbard: 100 shares Charles Eustis Hubbard: 10 shares Alexander Graham Bell: 1,497 shares Thomas Sanders: 1,497 shares Thomas Watson: 499 sharesThe Bell Telephone Company was incorporated in Massachusetts on July 30, 1878 with 4,500 shares of stock.
It merged with the New England Telephone and Telegraph Company to form the National Bell Telephone Company. A little over a year it was reorganized to become the American Bell Telephone Company. American Bell's outstanding stock rose to 258,863 shares by May 1900. Two days after the company's formation, on July 11, 1877, Bell married Hubbard's daughter Mabel Gardiner Hubbard, made a wedding gift of 1,487 shares of his allotment to his new wife, keeping only 10 shares for himself. Bell and his wife left not long after for a tour of Europe that lasted over a year, during which time Mabel left her shares with her father under a power of attorney, allowing him to become the new company's de facto president. Both Hubbard's and Sanders' roles in the newly born company were pivotal to its early survival and its eventual growth to become a corporate giant. Hubbard's early structuring of its telephone service by leasing, instead of selling telephones, was critical to its success, he based his decision on the previous legal work he performed for the Gordon McKay Shoe Machinery Company, where its shoe sewing machines were leased, not sold, royalties had to be paid to the Gordon McKay Company based on the numbers of shoes produced.
Hubbard insisted that leasing was the better option if it raised the need for initial capital expenses. Sanders for his part, a wealthy leather merchant, provided most of the financing for both Bell's research and the young company amounting to expenditures of some $110,000 "before he received any reimbursement" by the sale of his shares. Not long after the National Bell Telephone Company was established, it required substantial new capital in order to maintain its majority share ownership of its affiliate telephone companies and to provide further funds for expansion of its overall telephone infrastructure. On April 17, 1880, National Bell was split into the American Bell Telephone Company, led by Theodore Vail as general manager, with the International Bell Telephone Company as a holding company for its international subsidiaries. IBTC's first non-North American subsidiary was the Bell Telephone Manufacturing Company, established by Hubbard at Antwerp, Belgium, in 1882; the Bell System'
The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19, 1880, at Bell's laboratory at 1325 L Street in Washington, D. C. Both were to become full associates in the Volta Laboratory Association and financed by Bell. On June 3, 1880, Bell's assistant transmitted a wireless voice telephone message from the roof of the Franklin School to the window of Bell's laboratory, some 213 meters away. Bell believed. Of the 18 patents granted in Bell's name alone, the 12 he shared with his collaborators, four were for the photophone, which Bell referred to as his "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention made, greater than the telephone"; the photophone was a precursor to the fiber-optic communication systems that achieved worldwide popular usage starting in the 1980s. The master patent for the photophone was issued in December 1880, many decades before its principles came to have practical applications.
The photophone was similar to a contemporary telephone, except that it used modulated light as a means of wireless transmission while the telephone relied on modulated electricity carried over a conductive wire circuit. Bell's own description of the light modulator: We have found that the simplest form of apparatus for producing the effect consists of a plane mirror of flexible material against the back of which the speaker's voice is directed. Under the action of the voice the mirror becomes alternately convex and concave and thus alternately scatters and condenses the light; the brightness of a reflected beam of light, as observed from the location of the receiver, therefore varied in accordance with the audio-frequency variations in air pressure—the sound waves—which acted upon the mirror. In its initial form, the photophone receiver was non-electronic, using the photoacoustic effect. Bell found. Lampblack proved to be outstanding. Using a modulated beam of sunlight as a test signal, one experimental receiver design, employing only a deposit of lampblack, produced a tone that Bell described as "painfully loud" to an ear pressed close to the device.
In its ultimate electronic form, the photophone receiver used a simple selenium cell photodetector at the focus of a parabolic mirror. The cell's electrical resistance varied inversely with the light falling upon it, i.e. its resistance was higher when dimly lit, lower when brightly lit. The selenium cell took the place of a carbon microphone—also a variable-resistance device—in the circuit of what was otherwise an ordinary telephone, consisting of a battery, an electromagnetic earphone, the variable resistance, all connected in series; the selenium modulated the current flowing through the circuit, the current was converted back into variations of air pressure—sound—by the earphone. In his speech to the American Association for the Advancement of Science in August 1880, Bell gave credit for the first demonstration of speech transmission by light to Mr. A. C. Brown of London in the Fall of 1878; because the device used radiant energy, the French scientist Ernest Mercadier suggested that the invention should not be named'photophone', but'radiophone', as its mirrors reflected the Sun's radiant energy in multiple bands including the invisible infrared band.
Bell used the name for a while but it should not be confused with the invention "radiophone" which used radio waves. While honeymooning in Europe with his bride Mabel Hubbard, Bell read of the newly discovered property of selenium having a variable resistance when acted upon by light, in a paper by Robert Sabine as published in Nature on 25 April 1878. In his experiments, Sabine used a meter to see the effects of light acting on selenium connected in a circuit to a battery; however Bell reasoned that by adding a telephone receiver to the same circuit he would be able to hear what Sabine could only see. As Bell's former associate, Thomas Watson, was occupied as the superintendent of manufacturing for the nascent Bell Telephone Company back in Boston, Bell hired Charles Sumner Tainter, an instrument maker, assigned to the U. S. 1874 Transit of Venus Commission, for his new'L' Street laboratory in Washington, at the rate of $15 per week. On February 19, 1880 the pair had managed to make a functional photophone in their new laboratory by attaching a set of metallic gratings to a diaphragm, with a beam of light being interrupted by the gratings movement in response to spoken sounds.
When the modulated light beam fell upon their selenium receiver Bell, on his headphones, was able to hear Tainter singing Auld Lang Syne. In an April 1, 1880 Washington, D. C. experiment and Tainter communicated some 79 metres along an alleyway to the laboratory's rear window. A few months on June 21 they succeeded in communicating over a distance of some 213 meters, using plain sunlight as their light source, practical electrical lighting having only just been introduced to the U. S. by Edison. The transmitter in their latter experiments had sunlight reflected off the surface of a thin mirror positioned at the end of a speaking tube. Tainter, on the roof of the Franklin School, spoke to Bell, in his laboratory listeni
Thomas Alva Edison was an American inventor and businessman, described as America's greatest inventor. He is credited with developing many devices in fields such as electric power generation, mass communication, sound recording, motion pictures; these inventions, which include the phonograph, the motion picture camera, the long-lasting, practical electric light bulb, had a widespread impact on the modern industrialized world. He was one of the first inventors to apply the principles of mass production and teamwork to the process of invention, working with many researchers and employees, he is credited with establishing the first industrial research laboratory. Edison was raised in the American Midwest and early in his career he worked as a telegraph operator, which inspired some of his earliest inventions. In 1876, he established his first laboratory facility in Menlo Park, New Jersey, where many of his early inventions would be developed, he would establish a botanic laboratory in Fort Myers, Florida in collaboration with businessmen Henry Ford and Harvey Firestone, a laboratory in West Orange, New Jersey that featured the world's first film studio, the Black Maria.
He was a prolific inventor, holding 1,093 US patents in his name, as well as patents in other countries. Edison fathered six children, he died in 1931 of complications of diabetes. Thomas Edison was born, in 1847, in Milan and grew up in Port Huron, Michigan, he was the last child of Samuel Ogden Edison Jr. and Nancy Matthews Elliott. His father, the son of a Loyalist refugee, had moved as a boy with the family from Nova Scotia, settling in southwestern Ontario, in a village known as Shrewsbury Vienna, by 1811. Samuel Jr. fled Ontario, because he took part in the unsuccessful Mackenzie Rebellion of 1837. His father, Samuel Sr. had earlier fought in the War of 1812 as captain of the First Middlesex Regiment. By contrast, Samuel Jr.'s struggle found him on the losing side, he crossed into the United States at Sarnia-Port Huron. Once across the border, he found his way to Ohio, his patrilineal family line was Dutch by way of New Jersey. Much of his education came from reading R. G. Parker's The Cooper Union for the Advancement of Science and Art.
Edison developed hearing problems at an early age. The cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. Around the middle of his career, Edison attributed the hearing impairment to being struck on the ears by a train conductor when his chemical laboratory in a boxcar caught fire and he was thrown off the train in Smiths Creek, along with his apparatus and chemicals. In his years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, lifted him by the ears. Edison's family moved to Port Huron, Michigan after the canal owners kept the railroad out of Milan Ohio in 1854 and business declined. Edison sold candy and newspapers on trains running from Port Huron to Detroit, sold vegetables, he became a telegraph operator after he saved three-year-old Jimmie MacKenzie from being struck by a runaway train. Jimmie's father, station agent J. U. MacKenzie of Mount Clemens, was so grateful that he trained Edison as a telegraph operator.
Edison's first telegraphy job away from Port Huron was at Stratford Junction, Ontario, on the Grand Trunk Railway. He was held responsible for a near collision, he studied qualitative analysis and conducted chemical experiments on the train until he left the job. Edison obtained the exclusive right to sell newspapers on the road, with the aid of four assistants, he set in type and printed the Grand Trunk Herald, which he sold with his other papers; this began Edison's long streak of entrepreneurial ventures, as he discovered his talents as a businessman. These talents led him to found 14 companies, including General Electric, still one of the largest publicly traded companies in the world. In 1866, at the age of 19, Edison moved to Louisville, where, as an employee of Western Union, he worked the Associated Press bureau news wire. Edison requested the night shift, which allowed him plenty of time to spend at his two favorite pastimes—reading and experimenting; the latter pre-occupation cost him his job.
One night in 1867, he was working with a lead–acid battery when he spilled sulfuric acid onto the floor. It ran onto his boss's desk below; the next morning Edison was fired. His first patent was for the electric vote recorder, U. S. Patent 90,646, granted on June 1, 1869. Finding little demand for the machine, Edison moved to New York City shortly thereafter. One of his mentors during those early years was a fellow telegrapher and inventor named Franklin Leonard Pope, who allowed the impoverished youth to live and work in the basement of his Elizabeth, New Jersey, while Edison worked for Samuel Laws at the Gold Indicator Company. Pope and Edison founded their own company in October 1869, working as electrical engineers and inventors. Edison began developing a multiplex telegraphic system, which could send two messages in 1874. Edison's major innovation was the establishment of an industrial research lab in 1876, it was built in Menlo Park, a part of Raritan Township in Middlesex County, New Jersey, with the funds from the sale of Edison's qua
History of mobile phones
The history of mobile phones covers mobile communication devices that connect wirelessly to the public switched telephone network. While the transmission of speech by radio has a long history, the first devices that were wireless and capable of connecting to the standard telephone network are much more recent; the first such devices were portable compared to today's compact hand-held devices, their use was clumsy. Along with the process of developing a more portable technology, a better interconnections system, drastic changes have taken place in both the networking of wireless communication and the prevalence of its use, with smartphones becoming common globally and a growing proportion of Internet access now done via mobile broadband. Before the devices existed that are now referred to as mobile phones or cell phones, there were some precursors. In 1908, a Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and Power Company claimed to have developed a wireless telephone.
They were accused of fraud and the charge was dropped, but they do not seem to have proceeded with production. Beginning in 1918, the German railroad system tested wireless telephony on military trains between Berlin and Zossen. In 1924, public trials started with telephone connection on trains between Hamburg. In 1925, the company Zugtelephonie AG was founded to supply train telephony equipment and, in 1926, telephone service in trains of the Deutsche Reichsbahn and the German mail service on the route between Hamburg and Berlin was approved and offered to first-class travelers. Fiction anticipated the development of real world mobile telephones. In 1906, the English caricaturist Lewis Baumer published a cartoon in Punch magazine entitled "Forecasts for 1907" in which he showed a man and a woman in London's Hyde Park each separately engaged in gambling and dating on wireless telephony equipment. In 1926, the artist Karl Arnold created a visionary cartoon about the use of mobile phones in the street, in the picture "wireless telephony", published in the German satirical magazine Simplicissimus.
The Second World War made military use of radio telephony links. Hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some telephone companies in the 1940s. Early devices were bulky, consumed large amounts of power, the network supported only a few simultaneous conversations. Modern cellular networks allow automatic and pervasive use of mobile phones for voice and data communications. In the United States, engineers from Bell Labs began work on a system to allow mobile users to place and receive telephone calls from automobiles, leading to the inauguration of mobile service on June 17th 1946 in St. Louis, Missouri. Shortly after, AT&T offered Mobile Telephone Service. A wide range of incompatible mobile telephone services offered limited coverage area and only a few available channels in urban areas; the introduction of cellular technology, which allowed re-use of frequencies many times in small adjacent areas covered by low powered transmitters, made widespread adoption of mobile telephones economically feasible.
In the USSR, Leonid Kupriyanovich, an engineer from Moscow, in 1957-1961 developed and presented a number of experimental pocket-sized communications radio. The weight of one model, presented in 1961, could fit on a palm. However, in the USSR the decision at first to develop the system of the automobile "Altai" phone was made. In 1965, the Bulgarian company "Radioelektronika" presented a mobile automatic phone combined with a base station at the Inforga-65 international exhibition in Moscow. Solutions of this phone were based on a system developed by Leonid Kupriyanovich. One base station, connected to one telephone wire line, could serve up to 15 customers; the advances in mobile telephony can be traced in successive generations from the early "0G" services like MTS and its successor Improved Mobile Telephone Service, to first-generation analog cellular network, second-generation digital cellular networks, third-generation broadband data services to the state-of-the-art, fourth-generation native-IP networks.
In 1949, AT&T commercialized Mobile Telephone Service. From its start in St. Louis, Missouri, in 1946, AT&T introduced Mobile Telephone Service to one hundred towns and highway corridors by 1948. Mobile Telephone Service was a rarity with only 5,000 customers placing about 30,000 calls each week. Calls were set up manually by an operator and the user had to depress a button on the handset to talk and release the button to listen; the call subscriber equipment weighed about 80 pounds Subscriber growth and revenue generation were hampered by the constraints of the technology. Because only three radio channels were available, only three customers in any given city could make mobile telephone calls at one time. Mobile Telephone Service was expensive, costing US$15 per month, plus $0.30–0.40 per local call, equivalent to about $176 per month and $3.50–4.75 per call. In the UK, there was a vehicle-based system called "Post Office Radiophone Service,", launched around the city of Manchester in 1959, although it required callers to speak to an operator, it was possible to be put through to any subscriber in Great Britain.
The service was extended to London in 1965 and other major cities in 1972. AT&T introduced the first major improvement to mobile telephony in 1965, giving the improved service the obvious name of Improved Mobile Telephone Service. IMTS used additional radio channels, allowing more simultaneous calls in a given geographic area, introduced customer dialing, eliminating manual call setup by an operator, reduced the size and weight of the subscriber equipment. Desp