A. Comprehension

1. Define the term 'data transmission'.

2. Answer these questions:

1. What are me first examples of data transmission application?

2. Where is data transmission utilized?

3. What is the protocol?

4. When does handshaking occur?

5. What signals are referred to as asynchronous? Give some examples.

6. Which devices cooperate asynchronously?

7. What do synchronous protocols usually offer? Why?

8. Why are asynchronous protocols generally more flexible?

9. What are the advantages of asynchronous schemes?

10. Why do asynchronous data transfer schemes work well when relatively small amounts of data need to be transferred on an intermittent basis? What is an alternative?

3. Summarize the text using the words from Vocabulary Exercises.

B. Vocabulary

4. Give Russian equivalents of the following words and expressions: optional drift permit point-to-point dispatch routing commence clock signal intermittent value added dispense with check digit bandwidth handshaking optical fiber parity

clock circuitry prerequisite

5. Replace the underlined words and expressions with synonyms from the previous exercise. Translate the sentences into Russian.

1. Data transmission implies physical transmission of a message as a digital bit stream, represented as an electro-magnetic sig-

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nal, over a physical double-point or multipoint communication channel.

2. Examples of such channels are copper wires, light pipes, wireless communication channels, and storage media.

3. Telephone exchanges have become digital and software con- trolled, facilitating many cost attached services.

4. Connection acknowledgement must occur before data transmis- sion as it allows the protocol to be agreed.

5. As each byte of data has its own start and stop bits, a small amount of divergence or imprecision at me receiving end does not necessarily spell disaster since the device only has to keep pace with me data stream for a modest number of bits.

6. Data transmission is a subset of the field of data communica- tions, which also includes computer networking or computer communication applications and networking protocols, for example tracing and switching.

7. Synchronous signals do not require any extra negotiation as a precondition to data exchange.

8. The extra bits that frame incoming data tend to account for a significant part of the overall inter-machine traffic, hence consuming a portion of the communication throughput.

9. Actions that are measured against a time reference, or a beat wave, are referred to as synchronous actions.

10. The devices that behave asynchronously wait for the handshak- ing signals to change state, indicating that some transaction is about to start.

11. The handshaking signals are generated by the devices them- selves and can occur as needed, and do not require an outside supervisory controller such as a synchronization diagram mat dictates the occurrence of data transfer.

12. The RS-232C protocol uses an asynchronous scheme that al- lows flexible communication between computers and devices using byte-sized data blocks each framed with start, stop, and additional even bits on the data line.

13. Although asynchronous data transfer schemes like RS-232 work well when relatively small amounts of data need to be

transferred on a time-dependent basis, they tend to be sub- optimal during large information transfers. 14. To do without the extra handshaking signals and overhead, instead synchronizing the transmitter and receiver with a clock signal or synchronization information contained within the transmitted code before transmitting large amounts of information allows for collection and large batches of bytes of data sending, with a few bytes at me front-end that can be used for the synchronization and control.

6. Translate the words/expressions into English:

отправка, отправление; двухточечный, двухпунктовый; оп- товолокно; начинать(ся); дополнительный, необязательный; допускать, позволять; маршрутизация (в сети); схема синх- ронизации; обходиться без чего-л.; пропускная способность; предпосылка, предварительное условие; нестационарный (о сигнале); синхросигнал, тактовый сигнал; обмен с квити- рованием; подтверждение установления/квитирование связи; четность; добавленная стоимость; отклонение, смещение; контрольный разряд.