Telecommunication

Communication ties together the parts of a society just as the nervous system ties together the parts of an individual. From earliest times, when the only form of communication was speech, to the present, when electronic signals carry information instantly to practically any point on Earth, communication has been the way people have organized their cooperative activities. In the modern world there are two main types of communications media. One type consists of the mass media—such as television, radio, newspapers, and magazines—in which organizations send messages to a large number of people. The other type consists of direct, point-to-point communications—telephone, telegraph, data transmission, and postal service. Of these, the electronic media (all but the postal service) are termed telecommunications.

Telecommunication first came into existence with the development of the telegraph in the 1830s and 1840s. For the first time, news and information could be transmitted great distances almost instantaneously. The invention of the telephone in 1876 by Alexander Graham Bell fundamentally transformed telecommunications. The telephone system assumed its modern form with the development of dial phoning and its spread during the middle decades of the 20th century.

After 1975, however, a new transformation of telecommunications began. The technology used to carry information changed radically. At the same time ordinary telephone and telegraph traffic was enormously supplemented by huge masses of computer data, as millions of computers were tied together into global networks.

In most cases telecommunications systems transmit information by wire, radio, or space satellite. Wire transmission involves sending electrical signals over various types of wire lines such as open wire, multipair cable, and coaxial cable. These lines can be used to transmit voice frequencies, telegraph messages, computer-processed data, and television programs. Another somewhat related transmission medium that has come into increasingly wider use, especially in telephone communications, is a type of cable composed of optical fibers. Here electrical signals converted to light signals by a laser-driven transmitter carry both speech and data over bundles of thin glass or plastic filaments.

Radio communications systems transmit electronic signals in relatively narrow frequency bands through the air. They include radio navigation and both amateur and commercial broadcasting. Commercial broadcasting consists of AM, FM, and TV broadcasting for general public use.

Satellite communications allow the exchange of television or telephone signals between widely separated locations by means of microwaves—that is, very short radio waves with wavelengths from 10 centimeters to 1 centimeter. Since satellite systems do not require the construction of intermediate relay or repeater stations, as do ground-based microwave systems, they can be put into service much more rapidly.

Modern telecommunications networks thus not only send the traditional voice communications of telephones and the printed messages of telegraphs and telexes, they also carry images—the still images of facsimile machines or the moving images of video—television transmissions used in videoconferences in which the participants can see as well as hear each other. Additionally they carry encoded data ranging from the business accounts of a multinational corporation to medical data relayed for analysis by physicians thousands of miles from a patient.

2. Расставьте заголовки в тексте.

A Additional use.

B Means of communication.

C Some historical points.

D Microwaves serve people.

E Widely used communications.

F Flying waves.

3. Найдите в тексте английские эквиваленты.

	передает информацию мгновенно
	совместная деятельность
	средства связи
	средства массовой коммуникации
	прямая связь
	впервые появилась
	приняла современные формы
	дисковый телефон
	глобальная сеть
	многопарный кабель
	частота речевого диапазона
	оптическое волокно
	управляемый лазером передатчик
	пучок волокон
	диапазон частот
	радиотрансляция
	ультракороткие волны
	промежуточное реле
	усилительная станция
	неподвижный образ
	закодированные данные

4. Выберите слова из списка и заполните таблицу, чтобы получились словосочетания. Переведите словосочетания на русский язык.

nervous, to carry, cooperative, in the modern; to send, computer, to carry, short radio, global, amateur and commercial, in most, multinational

	world			data
	information			waves
	images			cases
	activities			system
	broadcasting			corporation
	network			messages

5. Вставьте предлоги.

the parts___a society; types___communications; consist___the mass media; large number___people; to come___existence; development___the telegraph; the invention___the telephone; to transmit information___wire; to transmit signal___the air; by means___microwaves; put___service;

6. Заполните таблицу и перескажите текст, опираясь на данные в таблице.