Sunday, 6 February 2011

Invention of telegraph

The word "telegraph" is derived from Greek and means "to write far"; so it is a very exact word, for to write far is precisely what we did when we sent a telegram. At the height of it use, telegraph technology involved a worldwide system of wires with stations and operators and messengers, that carried messages and news by electricity faster than any other invention before it.


The first crude telegraph system was made without electricity. It was a system of semaphores, or tall poles with movable arms, and other signaling apparatus, set within physical sight of one another.There was such a telegraph line between Dover and London at during the Battle of Waterloo; that related the news of the battle, which had come to Dover by ship, to an anxious London, when a fog set in (obscuring the line of sight) and the Londoners had to wait until a courier on horseback arrived.

Electrical Telegraph

The electrical telegraph is one of America's gifts to the world. The honor for this invention falls to Samuel Finley Breese Morse. Other inventors had discovered the principles of the telegraph, but Samuel Morse was the first to perceive the practical significance of those facts; and was the first to take steps to make a practical invention; which took him twelve long years of work.

In 1791, the French engineer Claude Chappe (1763-1805)

and his brother Ignace (1760-1829) invented the semaphore, an optical telegraph system that relayed messages from hilltop to hilltop using telescopes. The Chappes built a series of two-arm towers between cities. Each tower was equipped with telescopes pointing in either direction and a cross at its top whose extended arms could each assume seven easily-seen angular positions. Together, they could signal all the letters of the French alphabet as well as some numbers. Their system was successful and soon was duplicated elsewhere in Europe. It was Chappe who coined the word telegraph. He combined the Greek words tele meaning distance and graphien meaning to write, to define it as "writing at a distance." Its shortcomings however were its dependence on good weather and its need for a large operating staff. Advances in electricity would soon put this system out of business.

It was the invention of the battery and the resultant availability of electric charges moving at 186,000 mi (299,460 km) a second that accomplished this. Prior to this invention by the Italian physicist Alessandro Giuseppe A. A. Volta (1745-1827) in 1800, attempts to use electricity to communicate had failed because a dependable source of electricity was not available and the long, iron wires needed did not conduct electricity well and could not be properly insulated. Volta's new battery meant that experimenters had for the first time a reliable current of sufficient strength to transmit signals. The next major development was in 1819 when the Danish physicist Hans Christian Oersted (1777-1851) demonstrated that he could use an electric current to deflect a magnetic needle. Further, he showed that the direction of the movement depended on the direction of the flow of the current. This pointed the way to the true telegraph. While several researchers in different countries were attempting to exploit the communications aspects of this discovery, two Englishmen, William Fothergill Cooke (1806-1879) and Charles Wheatstone (1802-1875), formed a partnership and designed a five-needle telegraph system in 1837. Their system used needles to point to letters of the alphabet and numbers that were arranged on a panel. Their electric telegraph was immediately put to use on the British railway system. This system was used primarily for railroad signalling until 1845 when an event raised the

public's awareness of the potential of the telegraph. On New Year's Day, 1845, the telegraph was used to catch a murderer who had been seen boarding a train bound for London. The information was telegraphed ahead and the murderer was arrested, tried, and hanged.

Although Cooke and Wheatstone built the first successful telegraph based on electricity, it was an American artist and inventor, Samuel Finley Breese Morse (1791-1872), who would devise a telegraph method that would eventually become universally adopted. Morse had begun investigating telegraphy at about the same time as his English rivals, but he had no scientific background and was getting nowhere until he was informed about the 1825 invention of the electromagnet that had been made by the English physicist William Sturgeon (1783-1850). Fortunately for Morse, he took his inquiries to the American physicist Joseph Henry (1797-1878), who had built in 1831 an extremely powerful electromagnet (it could lift 750 lb [341 kg] compared to Sturgeon's 9 lb [4.1 kg]). More importantly, Henry had successfully experimented with using the electromagnet to transmit signals and clearly understood what would become the fundamental principle of the telegraph—the opening and closing of an electric circuit supplied by a battery. Henry gladly enlightened Morse on the mysteries of electromagnetism, and the determined Morse took it from there. He enlisted the aid of a young mechanic, Alfred Vail, and together they improved on the work Morse had already started. These early attempts using an electromagnet resulted in a pen touching a moving piece of paper to record a series of dots and dashes. This system presumes a coded message, and Morse had created his own system which, when he collaborated with Vail, resulted in the now-famous Morse code. Vail contributed significantly to the code, having visited a printer to determine which letters were most and least often used. Their code was then based on the most common letters having the simplest, shortest of symbols (dots and dashes). By 1837, they had put together a system which used a single, simple operator key which, when depressed, completed an electric circuit and sent a signal to a distant receiver over a wire. Their first public demonstration was made at Vail's shop in Morristown, New Jersey, and in 1843, the U. S. Government appropriated funds to build a pole line spanning the 37 mi (59.5 km) between Baltimore, Maryland and Washington, D.C. On May 24, 1844, the historic message, "What hath God wrought?" was sent and received. Once the system became practiced, it was found that skilled operators could "read" a message without looking at the dots and dashes on the paper by simply listening to the sound of the electromagnet's clicking. This led to the elimination of the paper and an even simpler electric telegraph system that used only a key, battery, pole line, and a new sounder to make the dot or dash clicking sound clear. Using such simple equipment and a single, insulated copper wire, Morse's telegraph system spread quickly across the United States and eventually replaced the older, English versions in Europe.

As the telegraph system grew and spread across the world, improvements followed fairly quickly. One of the first was Morse's development of a relay system to cover longer distances. His relay used a series of electromagnet receivers working on low current, each of which opened and shut the switch of a successive electric circuit supplied by its own battery. Telegraph use increased with the invention in Germany of the duplex circuit, allowing messages to travel simultaneously in opposite directions on the same line. In 1874, American inventor Thomas Alva Edison (1847-1931) designed a double duplex called a quadruplex. This higher-capacity system needed eight operators who handled four messages at one time, two in each direction. A high-speed automatic Morse system also had been invented by Wheatstone in 1858, whose punched-paper tape idea offered a means by which a message could be stored and sent by a high speed transmitter that could read the holes in the tape. This system could transmit up to 600 words per minute. The most revolutionary and innovative improvement however was a time-division, multiplex-printing telegraph system devised in 1872 by the French engineer, Jean Maurice Emile Baudot (1845-1903). His system was based on his new code which replaced the Morse code. It employed a five-unit code whose every character contained five symbol elements. The heart of his system was a distributor consisting of a stationary faceplate of concentric copper rings that were swept by brushes mounted on a rotating assembly. This logical system greatly increased the traffic capacity of each line and was so far ahead of its time that it contained many elements from which modern systems have evolved.

By the end of the nineteenth century, most of the world was connected by telegraph lines, including several cables that crossed the Atlantic Ocean. The first underwater conductor was laid by Morse in New York Harbor in 1842. Insulated with India rubber, it did not last long. After the German-English inventor, William Siemans (1823-1883) devised a machine to apply gutta-percha as insulation in 1847, submarine cables were laid across the English Channel from Dover, England to Calais, France in 1850-51. Unsuccessful attempts to span the Atlantic were made in 1857, 1858, and 1865, all under the guidance of American entrepreneur, Cyrus West Field (1819-1892). On July 27, 1866, Field was successful in his fourth attempt, and having connected the United States to Europe, he immediately returned to sea, recovered the lost 1865 cable, and had a second transatlantic telegraph cable working that same year. By 1940 there were 40 transatlantic cables in operation. Ten years later, some of these began to fail and were not repaired for economic reasons. In 1956, transatlantic telephone cables were first laid, and in 1966, the last of the exclusively telegraph cables were abandoned.

Throughout its history, the telegraph proved especially useful to the military. It was first used for these purposes in 1854 by the Allied Army in Bulgaria during the Crimean War. A transcontinental telegraph line had been completed in the United States just as the Civil War began, and the telegraph proved enormously useful to both sides. During the Spanish-American War in 1898, undersea telegraph cables were cut as an act of belligerency for the first time, and in World War I, teleprinters with secret codes were heavily used by all combatants.

The earliest teleprinter was invented by an American, Royal E. House, in 1846, only two years after Morse's first success. The transmitter had 28 character keys and employed a fairly crude system that even had a hand crank. Although it was used for only a few years, it was the forerunner of both the teleprinter and the stock ticker. At the turn of the century, a Nova Scotia inventor, Frederick G. Creed (1871-1957), experimented in Scotland with using a typewriter to send printed messages without using the Morse Code. His teleprinter system did not catch on in England, and in 1907, Charles L. Krumm of the United States designed the prototype version of the modern teleprinter. This system was subsequently improved, and during the 1920s became known by the American Telephone and Telegraph trade name, Teletype. Commercial teleprinter exchange services called TRX and Telex were developed during the next decade that were capable of printing up to 500 characters per minute. By 1964, this was up to 900 characters per minute. By then, technical improvements in the telephone had made an entire new range of technology available to telegraphy, and today, the telegraph has evolved into a modern digital data-transmission system. Today's modern systems use television coaxial cables, microwave, optical fiber, and satellite links to achieve an extremely high transmission rate.

The invention of the telegraph could in some ways be seen as the real beginning of our modern age, given the way in which it so interconnected the entire world. Almost coincidental with its birth there was the emergence of a new kind of journalism that made currency its stock in trade. Reporting events that had only just occurred took precedence over a newspaper's traditional editorial role, and news was reported almost as soon as it happened. Corporations also could become larger and more far-flung, and nations became necessarily more interdependent. With the telegraph, information—in all its aspects and forms—began to assume the critical role it plays today.

Invention and applicaion of telephone

Probably no means of communication has revolutionized the daily lives of ordinary people more than the telephone. The actual history of the telephone is a subject of complex dispute. The controversy began with the success of the invention and continues today. Some of the inventors credited with inventing the telephone include Antonio Meucci, Philip Reis, Elisha Gray and Alexander Graham Bell. Bell's experiments with his assistant Thomas Watson finally proved successful on March 10, 1876, when the first complete sentence was transmitted: "Watson, come here; I want you."
modern telephone is the culmination of work done by many individuals. Alexander Graham Bell was the first to patent the telephone, an "apparatus for transmitting vocal or other sounds telegraphically", after experimenting with many primitive sound
transmitters and receivers. However, the history of the invention of the
telephone is a confusing collection of claims and counterclaims, made no less confusing by the many lawsuits which attempted to resolve the patent claims of several individuals.

1831 Michael Faraday proved that vibrations of metal could be converted to electrical impulses.
1861 Johann Philip Reis built a apparatus that changed sound to electricity and back again to sound
1871 Antonio Meucci filed his patent caveat (notice of intention to take out a patent)
1874 A. G. Bell while working on a multiple telegraph, developed the basic ideas for the telephon
1875 Bell files first patent for improved telegraphy
1876 Bell and Watson transmit the first complete sentence
1876 Bell files patent application on February 14,. patent issues March 7
1876 Elisha Gray filed his patent caveat (notice of intention to take out a patent) on February 14,
1877 formed Bell Telephone Company to operate local telephone exchange operation
1877 first city exchange installed in Hartford, Connecticut
1879 irst exchange outside the United States was built in London, England
1880 invented the photophone, which transmits speech by light rays
1882 acquired a controlling interest in the Western Electric Company, Elisha Gray's company
1883 irst exchange linking two major cities was established between New York and Boston
1885 formed American Telephone and Telegraph Company to operate the long distance network.
1888 coin operated pay telephone was patented by William Gray of Hartford, Connecticut
1891 first automatic telephone exchange was patented by Almon Strowger of Kansas City
1921 The Detroit Police Department, began experimentation with one-way vehicular mobile service.
1928 Detroit Police commenced regular one-way radio communication with all its patrol cars.
1933 Bayonne, NJ Police Department initiated regular two-way communications with its patrol cars
1936 Alton Dickieson, H.I. Romnes and D. Mitchell begin design of AT&T's mobile phone system
1940 Connecticut State Police began statewide two-way, on the frequency modulated (FM)
1941 FM mobile radio became standard throughout the country following the success in Connecticut
1946 A driver in St. Louis, Mo., placed a phone call,it was the first AT&T mobile telephone call.
1948 wireless telephone service was available in almost 100 cities and highway corridors.
1947 cellular telephone service conceived by D.H. Ring at Bell Labs, but the technology didn't exist
1962 The first commercial touch-tone phones were a big hit in their preview at Seattle World's Fair.
1970 commercial Picture phone service debuted in downtown Pittsburgh, Pennsylvania.
1971 Richard Frenkiel and Joel Engel of AT&T applied computers and electronics to make it work.
1973 Martin Cooper of Motorola made the first cellphone call to his rival Joe Engel of AT&T Bell Labs
1978 AT&T conducted FCC-authorized field trials in Chicago and Newark, N.J.
1979 the first cellular network was launched in Japan.
1982 FCC granted commercial licenses to an AT&T subsidiary, Advanced Mobile Phone Service
1983 AMPS was then divided among the local companies as part of the planning for divestiture
1983 Illinois Bell opened the first commercial cellular system in October.

Simply described, it is a system which converts sound, specifically the human voice, to electrical impulses of various frequencies and then back to a tone that sounds like the original voice. In 1831, Englishman Michael Faraday (1791-1867) proved that vibrations of metal could be converted to electrical impulses. This was the technological basis

of the telephone, but no one actually used this system to transmit sound until 1861. In that year, Johann Philip Reis (1834-1874) in Germany is said to have built a simple apparatus that changed sound to electricity and back again to sound. A crude device, it was incapable of transmitting most frequencies, and it was never fully developed.

A practical telephone was actually invented independently by two men working in the United States, Elisha Gray and Scottish-born Alexander Graham Bell. Incredibly, both men filed for a patent on their designs at the New York patent office on February 14, 1876, with Bell beating Gray by only two hours! Although Gray had built the first steel diaphragm / electromagnet receiver in 1874, he wasn’t able to master the design of a workable transmitter until after Bell had. Bell had worked tirelessly, experimenting with various types of mechanisms, while Gray had become discouraged.

According to the famous story, the first fully intelligible telephone call occurred on March 6, 1876, when Bell, in one room, called to his assistant in another room. "Come here, Watson, I want you."

Watson heard the request through a receiver connected to the transmitter that Bell had designed, and what followed after that is a history of the founding of the Bell Telephone Company (later AT&T), which grew to be the largest telephone company in the world.

The first telephone system, known as an exchange, which is a practical means of communicating between many people who have telephones, was installed in Hartford, Connecticut in 1877, and the first exchange linking two major cities was established between New York and Boston in 1883. The first exchange outside the United States was built in London in 1879. The exchange involved a group of operators working at a large switchboard. The operators would answer an incoming telephone call and connect it manually to the party being called. The first automatic telephone exchange was patented by Almon Strowger of Kansas City in 1891 and installed in 1892, but manual switchboards remained in common use until the middle of the twentieth century.

The coin operated pay telephone was patented by William Gray of Hartford in 1889. The first rotary dial telephone was developed in 1923 by Antoine Barnay in France. The mobile telephone was invented by Bell Telephone Company and introduced into New York City police cars in 1924. Although the first commercial mobile telephone service became available in St. Louis, Missouri in 1946, the mobile telephone would not become common for another four decades.

The first touch-tone system - which used tones in the voice frequency range rather than pulses generated by rotary dials - was installed in Baltimore, MD, in 1941. Operators in a central switching office pushed the buttons; it was much too expensive for general use. However, the Bell System was intrigued by touch-tone because it increased the speed of dialing.

By the early 1960s, low-cost transistors and associated circuit components made the introduction of touch-tone into home telephones possible. Extensive human factors tests determined the position of the buttons to limit errors and increase dialing speed even further. The first commercial touch-tone phones were a big hit in their preview at the 1962 Seattle World's Fair.

The first Picturephone test system, built in 1956, was crude—it transmitted an image only once every two seconds. But by 1964 a complete experimental system, the "Mod 1," had been developed. To test it, the public was invited to place calls between special exhibits at Disneyland and the New York World’s Fair. In both locations, visitors were carefully interviewed afterward by a market research agency.

People, it turned out, didn’t like Picturephone. The equipment was too bulky, the controls too unfriendly, and the picture too small. But the Bell System was convinced that Picturephone was viable. Trials went on for six more years. In 1970, commercial Picturephone service debuted in downtown Pittsburgh and AT&T executives confidently predicted that a million Picturephone sets would be in use by 1980.

What happened? Despite its improvements, Picturephone was still big, expensive, and uncomfortably intrusive. It was only two decades later, with improvements in speed, resolution, miniaturization, and the incorporation of Picturephone into another piece of desktop equipment, the computer, that the promise of a personal video communication system was realized.

In 1978, American Telephone and Telegraph’s (AT&T) Bell Laboratories began testing a mobile telephone system based on hexagonal geographical regions called cells. As the caller’s vehicle passed from one cell to another, an automatic switching system would transfer the telephone call to another cell without interruption. The cellular telephone system began nationwide usage in the United States in 1983.