Introductory text

Notes to the text:

transmitting and receiving messages – передача та отримання повідомлень

flat images – пласкі зображення

satellite communication channels – канали супутникового зв’язку

cells – стільники

effective range – радіус дії

cluster – кластер

digital cell communication – цифровий стільниковий зв’язок

long-distance telephone service – міжміське телефонне обслуговування

Telegraph and Telephone

Communication is a set of electrical and electronic means of messaging. Electrical means of communication were invented in the 19-th century. They were telegraph and telephone where information was transmitted by electrical signals through wires.

The basis of telegraphy was laid by Shilling in 1832 in Russia. Shilling designed the first complex of devices for electrical telegraph communication. In 1837 an American inventor Morse constructed an electromechanical telegraph apparatus for transmitting and receiving messages by means of a special code. The transmitter of his apparatus was a telegraph key, the receiver was an electromagnet. The first telegraph communication line equipped with Morse apparatus was put into operation in 1844 in the USA.

Since that time telegraph communication has been improved. Modern means of telegraph communication are telex and fax. Telex is an international teleprinter exchange service and fax is phototelegraphy. It is based on the achievements of electronics, radio engineering, electrical engineering and optics. Fax (abbreviation of ‘facsimile’) is the system of transmitting stationary flat images using cable radio relay and satellite communication channels. It is widely used for quick transmission of central newspapers’ texts and photos, documents, schemes and drafts. But for telex and fax we shouldn’t receive the latest news so fast.

The history of telephone communication goes back to 1876 when an English inventor Bell designed the first telephone apparatus. The first telephone station was built in 1878 in the USA. Telephone communication is based on converting sound vibrations into electrical signals at the microphone, transmitting these signals along the cable and reconverting them into sound vibrations of speech at the receiver. Telephone communication with moving objects is performed by means of radiotelephone. Without radiotelephone we couldn’t communicate with ships, aircrafts, automobiles and other vehicles.

The first generation of mobile communication systems dates back from the middle of 1940-s when the Bell Laboratories Research Centre (USA) put forward an idea of dividing an area into small parts called cells. Every cell is served by a transmitter of a limited effective range and a limited number of channels. Different frequencies are used in different cells. Several cells are grouped into a cluster. A cluster may have up to 15 cells. Such a system is called an analogue system of cell communication.

The second generation of mobile communication systems was born in the late 1980-s on the basis of digital methods of signal processing. Such systems represent a fully connected network of computing devices. The Global System for Mobile Communications (GSM) was developed in 1982. It is a unified all-European standard of digital cell communication used in many countries. Digital cell communication possesses the best technical and economic characteristics. It is widely used in telephony, radio broadcasting and television. The number of users of analogue and digital mobile communication systems in the world amounts to tens of millions. Digital cell communication is generally used in long-distance and international telephone service. At present almost all of long-distance and international telephone stations work on the basis of digital cell systems.