IX. Form Participle I and Participle II of the following verbs:

to carry, to be, to follow, to make, to find, to begin, to see, to think, to become, to mean, to know, to understand, to invent, to discover, to change, to transmit, to simplify.

X. Translate the following sentences paying attention to Participle I and Participle II:

1. The exchanges operating automatically are of great value. 2. The developing industry meets the demands of the people. 3. All the students taking part in this work must be at the Institute at 9 o'clock. 4. The following effect will take place. 5. There are very many illustrated magazines in our reading-room. 6. The articles published in this magazine are very interesting. 7. You can get the books recommended by the teacher in our library. 8. They saw new types of machine tools at one of the plants visited. 9. We sent the letter to the address indicated. 10. The examples given illustrate the rule.

XI. Read the following supplementary text and translate it using a dictionary. Put your own questions on the text and discuss them with your fellow-students; entitle it.

SUPPLEMENTARY TEXT

There are several techniques used for the transfer of data communication signals. Each has its particular advantages. Standard data communication messages are sent in some form of a pulse code. There are several varieties of pulsed codes that are used in the transferral of data in digital form. Binary signals, by their very nature, are natural elements for digital codes. Such codes are said to be in "binary format".A binary formatted code can represent different symbols only by allowing sufficient binary elements for each symbol. If we think of one binary digit (or bit) representing each symbol, we have only two choices: one symbol represented by the "on" state, the other represented by the "off" state. With such an arrangement, we could let the "on" or one-state represent "no" and the "off" or zero-state represent "yes". If, instead of using one binary digit for our character, we use two, we now have more characters to choose from. Our choice for a one-bit code was limited to two: 0 or 1. Our choice for a two-bit code is four: 00, 01, 10 or 11. If we choose a three-bit code, our choice is eight: 000, 001, 010, 011, 100, 101, 110 and 111. It can be shown that for a code with a character make up of n bits the number of characters available will be 2ⁿ.

In order to transmit code characters it is necessary to arrange their elements in a way that will allow their reception without uncertainty. There are several techniques by which this may be done; these fall into two broad categories: serial data transmission and parallel data transmission. In parallel data transmission, each element of a code has its own channel so that the total character is transmitted at the same time. This means that a five-level code, for example, would have five channels in parallel transmission set-up. In serial data transmission, each element of a code character is sent in turn rather than sending all elements at once. This technique allows binary coded multi-level data to be transmitted over a single channel.