Translate the following sentences;

1. The transmitter consists of..

- a microphone housing, a carbon chamber, a carbon dia­phragm, carbon granules, an insulating spacer, and a
conductor.

2. Carbon granules...

- pass current.

- either decrease the resistance or increase the resistance.

3. Telephony...

- is widely used in our country.

- enables us to transmit sound energy.

4. Read and translate the questions. Find answers to
the question in the text:

1. By what means are people able to communicate with each other over long distances? 2. What part of the tele­phone is pressed to our ear?
3. What part do we speak into? 4. What is the transmission of oscillations? 5.Should the frequency of oscillations be constant or

took their toll; at the present time there are approxi­mately 1, 300 local exchange carriers.

Unfortunately for the general public, all of these telephones were not interconnected. Therefore, it was necessary for a subscriber to have two or three instru­ments to communicate with the total population of the city. However, the great asset of AT& T, which became the official name of the company at the end of 1899, was the control of all the long-distance circuits and its steadfast refusal to interconnect any other company to it.

This would never do, and the Justice Department filed suit in 1912. The world was angry with AT& T, and an AT& T vice president - Nathan C. Kingsbury - real­ized it. He recognized that the best demonstration of AT& T not being in a monopoly position was to point to thousands of independents apparently operating in har­mony. To this end AT& T agreed to provide interconnec­tion arrangements to all independents. This 1913 agree­ment was henceforth called the Kingsbury Commitment.

By 1934 telecommunications had become so im­portant to the country that Congress passed a Communi­cations Act and, simultaneously, created the Federal Communications Commission (FCC). The section of this Act that has turned out to be most important has to do with what we now call universal service. It said: " For the purpose of regulating interstate and foreign commerce/in communication by wire and radio so as to make avail­able, so far as possible, to all the people of the United States a rapid, efficient, nationwide, and worldwide wire and radio communication service with adequate facilities at reasonable charges."

As a result of this principle, a support structure
has been established whereby certain groups of sub-

The manual system required, of course, constant attention from operators. In the late 1800s, telephone calls were connected manually at the CO. When a call came in, an attendant would plug into a horizontal bar line. He then would yell to the operator who handled the customer being called, and that second operator would connect to the bar and finish setting up the call. When the call was completed, another operator would yell to all in the room that the line was clear again. The step-by-step system, which is still in operation in many parts of the country, utilized what is known as the Strowger switch. The intelligence in the system was located in re­lays mounted on each switch. The switch itself re­sponded to the dial pulses of the rotary dial

The crossbar system was still electromechanical in nature, but the intelligence of the system was separated from the actual switch. Thus, this common control could be used repeatedly to set up and tear down calls and never sit idle.

When electronics came along, the electromechani­cal control of the common control system was replaced with electronics, and the network, or matrix, was usually replaced with tiny glass-encapsulated reed switches. Hence,, only a part of the switch was electronic, In the next generation, the stored program operation of a digital computer was applied to the switch, although the net­work remained a complex of reed switches. In the final generation, called a digital switch, the talking path was no longer an electrically continuous circuit; rather the speech being carried was digitized into a stream of " Is" and " Os." Notice that this final generation depicted a significant change from the previous generations in that there was no longer an electrical talking path through the

switch. We were, in fact operating in a digital (rather than analog) domain.

However, whether the system was analog or digi­tal, one thing must be recognized: there was an actual talking path - a circuit - from the calling party to the called party. This talking path was established at the be­ginning of a call and held for the duration of a call. We call it circuit switching. This system is not actually effi­cient. When I am talking, you are listening, and the cir­cuit is being used in only one direction - that is, 50 per­cent. When you are talking and I am listening, it is still 50 percent. When neither of us is talking, or when there is silence between words, the efficiency is 0 percent.

There is, however, a different kind of connection, and we see it today in a number of applications:

• credit-card verification;

• automated teller machine;

• SS7;

«Internet and the World Wide Web.

This system is called packet switching (as opposed to circuit switching). In a packet - switching system, the information being transmitted (be it data or digitized voice) is not sent in real time over a dedicated circuit; rather it is stored in a nearby computer until a suffi­ciently sized packet is on hand. Then a very smart com­puter seizes a channel heading in the general direction of the destination, and that packet of data is transmitted at very high speeds. Then the channel is released. So, ex­cept for some necessary supervisory information (desti­nation, error checking codes, etc.) the channel is 100 percent efficient.

When the distant station gets that message no
more than a few milliseconds later, it responds with the

upward, the wire would be withdrawn from the conduct­ing liquid, and its resistance would be increased.

It was this device that was ultimately successful and that formed the basis for the telephone industry for many years.

A year later, on July 9, 1877, the Bell Telephone Company was formed, and Alexander Graham Bell be­came the company's electrician, at a salary of $3, 000, and Watson became superintendent in charge of research and manufacturing. Unfortunately for Bell, the basic pat­ents were due to run out in 1893 and 1894. But by this time, Theodore Newton Vail had been brought in as gen­eral manager, and he immediately set about establishing an organization strong enough to survive without a mo­nopoly. " What we wanted to do was get possession of the field in such a way that, patent or no patent, we could control it, " Vail said. The first step was to obtain a captive manufacturing facility, and this was accom­plished in 1881 with the purchase of Western Electric Company.

Vail also sent his salesmen into the field to set up telephone exchanges in virgin territory. Generally, local promoters were encouraged to organize a local telephone company and sell stock. Thus, by 1885 Vail had estab­lished a vertically integrated supply division, a network of companies licensed by the parent, and a strong re­search and development arm. The expiration of Bell's ba­sic patents in 1893 and 1894 was the starting signal for open competition. Independent telephone operating com­panies sprang up throughout the country; by the turn of the century there were approximately 6, 000 of them, and these 6, 000 provided service to some 600, 000 subscrib­ers. Through the years, mergers and acquisitions took

so as to make available, so far as possible, to all the peo­ple of the United States a rapid, efficient, nationwide, and worldwide wire and radio communication service with adequate facilities at reasonable charges".

5. In 1949 the Justice Department again filed suit against AT& T, claiming that Western Electric charged inordinately high prices from their customers (i.e., the operating telephone companies owned by AT& T), thus making it possible for the operating telephone compa­nies to charge their subscribers inappropriately high rates.

Task 3