Page 38 - Encyclopedia Of World History Vol V

telegraph and telephone 1815

This diagram shows the structure of
Morse's telegraph system.
Line

Spring tion of an industry that now connects people throughout
the world.
Coil
At first, telephone networks were mainly local or, at
best, regional, for transmission quality deteriorated with
distance. Service was expensive, as calls had to be
switched by operators in telephone exchanges. Beginning
in the 1890s, rotary dials and automatic switches per-
mitted a great expansion of service without additional
labor. In the United States and Canada, many inde-
pendent companies competed with the giant AT&T
1866 with the laying of the first successful transatlantic (incorporated in 1885), especially in rural areas. In
cables. That success encouraged entrepreneurs to lay Europe, telephone service was provided by the govern-
cables in other parts of the world: from Europe to India ment, usually by the postal and telegraph administration.
in 1870, to Australia, China, and Latin America in the Outside of Europe and North America, telephones were
early 1870s, and around Africa in the 1880s. By the end very rare before World War II, usually limited to govern-
of the century, all the continents and major islands were ment offices and major businesses.
connected in a global network dominated by Western In 1915 AT&T installed vacuum tube repeaters on its
Union and the Commercial Cable Company in the North longer lines, making it possible to connect New York and
Atlantic and elsewhere by a British firm, the Eastern and San Francisco. A dozen years later, it became possible,
Associated Telegraph Companies.The global submarine though it was extremely expensive, to telephone overseas
cable network played a major role in the growth of the or to ships at sea.
world economy and international trade before World War By the mid-twentieth century, the telephone industry,
I, during the first age of globalization.That network was like the telegraph industry before it, had become mature
also strategically valuable, and gave Britain, France, and and technologically conservative. In the United States,
the United States a significant advantage over Germany local telephone service reached all businesses and most
in World War I. families by the 1950s, but long-distance service was still
Other advances in telegraph technology improved too costly for the majority of users. In Europe and Latin
transmission speeds and reduced labor costs. Thus America, the cost of telephone service was out of reach
multiplexing—sending several messages simultaneously of the working class. Elsewhere, telephone service was a
over the same wire—was introduced in the 1870s and, business tool and a luxury for the urban rich.
starting in the 1920s, automatic teletypewriters and vac- Then came a series of innovations that revolutionized
uum tube repeaters replaced the manual typing and the industry and its social effects. The first transatlantic
retransmitting of messages. Facsimile transmissions telephone cable, laid in 1956, could carry a dozen calls
(faxes) began in the 1930s. By then, however, wired teleg- at once; it was soon duplicated and extended to other
raphy had fallen far behind two radically different tech- oceans. Starting in the 1960s, satellites and inexpensive
nologies: telephony and radio. transmission stations made global telephony cheap and
available worldwide by multiplying the number of tele-
Telephony phone conversations that could be sent at the same time.
In 1876,Alexander Graham Bell (1847–1922) patented On land, microwave towers dramatically lowered the
a method of transforming sound into electrical impulses cost of long-distance communications. Fiber-optic
and vice versa, thereby making it possible to transmit the cables, introduced in the 1980s, could carry hundreds of
human voice over a wire. His invention was the founda- thousands of simultaneous telephone conversations.