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To be read after Lesson 4


A group of people enter a room, the lights go down, the screens come... the videoconference is under way.

Tomorrow's scientific fiction has become today's new technol­ogy -a daily reality for global companies who recognise the impor­tance of regular communication between groups of people in different locations around the world.

Essentially the videoconference room resembles a usual confer­ence room. Delegates sit along one side of a table facing their col­leagues on screen on the other side. They can see, hear and talk to each other simultaneously and can present slides of diagrams, even pieces of equipment. The technology is relatively simple. A device called videocodec takes the picture, digitalizes it for transmission over a special network and reforms the picture at the other end.

The problem today is to manufacture codec to the new interna­tional standard and to improve picture quality through faster trans­mission speeds. Research and development is also focusing on mobile videoconferencing with broadcast quality pictures which enable to have instant communication with colleagues around the world.

There is no doubt about the effectiveness of videoconferencing, as the videoconference eliminates the working time lost through travel.

The First Travelling Post Office

The first travelling post office in the United States was Abra­ham Lincoln's hat. That was a strange place, indeed, for mail; but that is where it was kept. Lincoln was appointed postmaster of New Salem, a small Western town, about the year 1833. The postman visited the place once a week and brought the mail — a dozen let­ters, perhaps, and two or three newspapers — in his saddle (ñåäëî) bags. He was always met by Postmaster Lincoln who put the letters into his hat for safekeeping. Lincoln was also the clerk in the coun­try store, so he had a good opportunity to distribute the mail. But if

people did not come for it, he put on his hat and delivered it. So New Salem was the first town in the US to have rural free delivery, even though the postmaster received very small pay for his work. At that time, stamps and envelopes were not used. When the sender of a letter paid the postal charges, the postmaster wrote PAID in the large letters on the face of the letter. But the postal rates were so high that the sender seldom paid them. Thus, the mailing charges were usually collected from the person who received the mail. The postmaster always held his postal receipts until a government rep­resentative came for them.

The Internet

The Internet is a magnificent global network with millions and millions of computers and people connected to one another where each day people worldwide exchange an immeasurable amount of information, electronic mail, news, resources and, more impor­tant, ideas.

It has grown at a surprising rate. Almost everyone has heard about it and an increasing number of people use it regularly. The current estimate is that over 70 million people are connected, in some way, to the Internet — whether they know it or not.

With a few touches at a keyboard a person can get access to ma­terials in almost everywhere. One can have access to full-text news­papers, magazines, journals, reference works, and even books. The Web is one of the best resources for up-to-date information. It is a hypertext-based system by which you can navigate through the Internet. Hypertext is the text that contains links to other docu­ments. A special program known as «browser» can help you find news, pictures, virtual museums, electronic magazines, etc. and print Web pages. You can also click on keywords or buttons that take you to other pages or other Web sites. This is possible because browsers understand hypertext markup language or code, a set of commands to indicate how a Web page is formatted and displayed.

Internet Video conferencing programs enable users to talk to and see each other, exchange textual and graphical information, and collaborate.

Internet TV sets allow you to surf the Web and have e-mail while you are watching TV, or vice versa. Imagine watching a film on TV and simultaneously accessing a Web site where you get in­formation on the actors of the film. The next generation of Internet-enabled televisions will incorporate a smart-card for

home shopping, banking and other interactive services. Internet-enabled TV means a TV set used as an Internet device.

The Internet is a good example of a wide area network (WAN). For long-distance or worldwide communications, computers are usually connected into a wide area network to form a single inte­grated network. Networks can be linked together by telephone lines or fibre-optic cables. Modern telecommunication systems use fi­bre-optic cables because they offer considerable advantages. The cables require little physical space, they are safe as they don't carry electricity, and they avoid electromagnetic interference.

Networks on different continents can also be connected via sat­ellites. Computers are connected by means of a modem to ordinary telephone lines or fibre-optic cables, which are linked to a dish ae­rial. Communication satellites receive and send signals on a trans­continental scale.

Date: 2015-12-17; view: 1537

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IGNITION FUNDAMENTALS | To be read after Lesson 5
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