Telegraphy is a form of data communication that is based on the use of a signal code. The word telegraphy comes from Greek tele meaning “distant” and graphein meaning “to write”—writing at a distance. The inventor of the first electric telegraph was Samuel Finley Breese Morse, an American inventor and painter.
On a trip home from Italy, Morse became acquainted with the many attempts to create usable telegraphs for long-distance telecommunications. He was fascinated by this problem and studied books on physics for 2 years to acquire the necessary scientific knowledge.
Morse focused his research on the characteristics of electromagnets, whereby they became magnets only while the current flows. The intermittence of the current produced two states—magnet and no magnet—from which he developed a code for representing characters, which eventually became known as Morse Code. (The International Morse Code is a system of dots and dashes that can be used to send messages by a flash lamp, telegraph key, or other rhythmic device such as a tapping finger.)
His first attempts at building a telegraph failed, but he eventually succeeded with the help of some friends who were more technically knowledgeable. The signaling device was very simple. It consisted of a transmitter containing a battery and a key, a small buzzer as a receiver, and a pair of wires connecting the two. Later, Morse improved it by adding a second switch and a second buzzer to enable transmission in the opposite direction as well.
In 1837, Morse succeeded in a public demonstration of his first telegraph. Although he received a patent for the device in 1838, he worked for 6 more years in his studio at New York University to perfect his invention. Finally, on May 24,1844, with a $30,000 grant from Congress, Morse unveiled the results of his work. Over a line strung from Washington, D.C., to Baltimore, Morse tapped out the message, “What hath God wrought.”
The message reached Morse’s collaborator, Alfred Lewis Vail, in Baltimore, who immediately sent it back to Morse. With the success of the telegraph assured, the line was expanded to Philadelphia, New York, Boston, and other major cities and towns. The telegraph lines tended to follow the rights-of-way of railroads, and as the railroads expanded westward, the nation’s communications network expanded as well.
Morse Code uses a system of dots and dashes that are tapped out by an operator using a telegraph key. (It also can be used to communicate via radio and flash lamp.) Various combinations of dots and dashes represent characters, numbers, and symbols separated by spaces.
Morse Code is the basis of today’s digital communication. Although it has virtually disappeared in the world of professional communication, it is still used in the world of amateur radio (HAM) and is kept alive by history buffs. There are even pages on the Web that teach telegraphy and perform translations of text into Morse Code.
Wireless Telegraphy
An Italian inventor and electrical engineer, Guglielmo Marconi (1874–1937), pioneered the use of wireless telegraphy. Telegraph signals previously had been sent through electrical wires. In experiments he conducted in 1894, Marconi demonstrated that telegraph signals also could be sent through the air.
A few years earlier, Heinrich Hertz had produced and detected the waves across his laboratory. Marconi’s achievement was in producing and detecting the waves over long distances, laying the groundwork for what today we know as radio. So-called Hertzian waves were produced by sparks in one circuit and detected in another circuit a few meters away.
By continuously refining his techniques, Marconi could soon detect signals over several kilometers, demonstrating that Hertzian waves could be used as a medium for communication. The results of these experiments led Marconi to approach the Italian Ministry of Posts and Telegraphs for permission to set up the first wireless telegraph service. He was unsuccessful, but in 1896, his cousin, Henry Jameson-Davis, arranged an introduction to Nyilliam Preece, engineer-inchief of the British Post Office.
Encouraging demonstrations in London and on Salisbury Plain followed, and in 1897, Marconi obtained a patent and established the Wireless Telegraph and Signal Company, Ltd, which opened the world’s first radio factory at Chelmsford, England, in 1898. Experiments and demonstrations continued. Queen Victoria at Osborne House received bulletins by radio about the health of the Prince of Wales, convalescing on the royal yacht off Cowes.
Radio transmission was pushed to greater and greater lengths, and by 1899, Marconi had sent a signal 9 miles across the Bristol Channel and then 31 miles across the English Channel to France. Most people believed that the curvature of the earth would prevent sending a signal much farther than 200 miles, so when Marconi was able to transmit across the Atlantic in 1901, it opened the door to a rapidly developing wireless industry.
Commercial broadcasting was still in the future—the British Broadcasting Company (BBC) was established in 1922—but Marconi had achieved his aim of turning Hertz’s laboratory demonstration into a practical means of communication.
By Morse’s death in 1872, the telegraph was being used worldwide and would pave the way for the invention of the telephone. Western Union had the monopoly on commercial telegraph service but spurned Alexander Graham Bell, who approached the company with an improvement that would convey voice over the same wires.
Bell had to form his own company, American Bell Telephone Company, to offer a commercial voice communication service. Since then, voice and data technologies have progressed through separate evolutionary paths. Only in recent years has voice-data integration been pursued as a means of containing the cost of telecommunication services.
