1 Answer the following questions:

1 What do Americans call a telephone exchange?

2 Who invented the telephone? When and where?

3 What did the first operators do?

4 Why did Strowger invent the automatic telephone exchange?

5 What is a 'crossbar' system?

6 What advantages does crossbar offer over Strowger?

7 What important development took place in 1948?

8 What are mechanical and electromechanical exchanges being replaced by?

2 Complete the following table: Main characteristics of the systems

1880 …..System	1892 ..… System	1940s …… System	1948 ….. System	1970 ….. System
First, simple exchanges. Connections manually established

3 Choose from part II the appropriate continuation of the sentences.

1 In the field of telecommunications, a telephone exchange or telephone switch is …….

2 Prior to the telephone, electrical switches were …….

3 Later exchanges consisted of one to several hundred plug boards …….

4 In 1891, Strowger patented the stepping switch, …….

5 Exchanges based on the Strowger switch were ……..

II 1 …… a device which led to the automation of the telephone circuit switching.

2 ……. challenged by other selectors and by crossbar technology.

3 ……. a system of electronic components that connects telephone calls.

4 ……. used to switch telegraph lines.

5 …... staffed by telephone operators.

4 Put the verb in brackets into the correct tense.

1 Strowger’s automatic exchange (undergo) several modifications.

2 Bell (speak) the first word on the telephone in 1876.

3 Over the last few years, electromechanical exchanges (begin) to disappear.

4 In the early exchanges, all calls (go) through the operator.

5 With digital techniques, telephone exchanges (just undergo) another great change.

6 Strowger (patent) his idea in 1889.

5 Read the following paragraph. Fill in each blank with a suitable word given below.

Switched, replaced, automated, dial, existence, eliminate, operators, connections, exchanges, switch, call, for, from, another, device, automatic.

Automatic exchanges, or ____ service, came into ____ in the early 1900s. Their purpose was to ____ the need ____ human telephone ____. Before the exchanges became ____, operators had to complete the ____ required for a telephone ____. Almost everywhere, operators have been ____ by computerized ____. A telephone ____ is the brains of an ____ exchange. It is a ____ for routing calls ____ one telephone to ____, generally as part of the public ____ telephone network.

6 Make up a summary of the text using the cliché:

1 This text is about…

2 The title of the text is…

3 The text consists of three (four) parts…

4 At the beginning the author describes…

5 The main idea of the text is…

6 The text provides useful information on…

Text 2

Switching technologies

Most of the world's telephone traffic is still handled by exchanges of electromechanical design, each with thousands of wear-prone exposed moving parts. Analogue exchanges of this type are costly to install and maintain, and are subject to familiar faults such as crossed lines, noise and wrong numbers.

Many of the world's telecommunications administrations have explored other, digital, solutions. They are designing networks that offer: a much higher quality of service than before, using the latest microchip technology with few or no moving parts; less interference than previously; lower installation and maintenance costs; and much faster connection speed for calls and fewer wrong numbers than in the past. The main characteristics of a digital exchange are: