Exercises:

1. Give Russian equivalents of the following phrases:

Used in data communications; communications hardware such as modems; two rubber cups; very susceptible to noise; easily transmit and receive;

2. Say if the following sentences are true or false.

1. You should become familiar with communications hardware such as modems, which were mentioned briefly in the section on analog and digital signals, multiplexers, concentrators, controllers, front-end processors, and protocol converters. 2. Modems aren’t probably the most widely used data communications hardware in business. 3. They aren’t certainly the most familiar to microcomputer users who communicate with one another or with a larger computer. 4. The direct-connect modem allows the user to directly connect the computer to the telephone line. 5. Some modems don’t run at 9,600 to 19,600 bps, but these modems, used with mini-and mainframe computers, are often more expensive than many microcomputers.

3. Insert missing words, use the text’s vocabulary:

1. Much … used in data communications is operated by technical professionals and rarely of immediate consequence to the user unless it stops working –when you’re calling New York and can’t reach your division office in London. 2. As you know the word modem is actually a contraction of … and … . 3. For many years, the … coupler was the most widely used. 4. In contrast, the … … modem allows the user to directly connect the computer to the telephone line. 5. Some modems run at … to … bps, but these modems, used with mini-and mainframe computers, are often more expensive than many microcomputers.

4. Translate these sentences into your native language:

1. As you know the word modem is actually a contraction of modulate and demodulate; a modem’s basic purpose is to convert digital computer signals to analog signals for transmission over phone lines, then to receive these signals and convert them back to digital signals. 2. Most modems are categorized according to how they connected to the telephone line: acoustic or direct-connect. 3. The connection is then made acoustically (by sound). 4. As a result, they are now considered nearly obsolete. 5. In contrast, the direct-connect modem allows the user to directly connect the computer to the telephone line.

5. Retell the text.

Text 17

Multiplexers, Concentrators, and Controllers

Words and word combinations:

Often become overtaxed – часто становятся обремененными налогами

dedicated lines – предназначенные линии

multiple users or devices – многочисленные пользователи и приборы

to share one high-speed line – делить одну высокоскоростную линию

temporarily store – временно хранить

directs them to their recipients – направлять их к их получателям

do error checking and retransmission – делать проверку ошибок и отправить вновь

to get data from one place to another – доставить данные из одного места в другое

When an organization’s data communications needs grow, the number of lines available for that purpose often become overtaxed, even if the company has leased one or more private telephone lines- called dedicated lines- used only for data communications. Multiplexing optimizes the use of communications lines by allowing multiple users or devices to share one high-speed line, thereby reducing communications costs. Multiplexers, concentrators, or controllers can do multiplexing