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provides connectivity between hosts on the same local network link, such as a LAN or a dial-up connection.

The most prominent component of the Internet model is the Internet Protocol which provides addressing systems (IP addresses) for computers on the Internet.

Дайте відповіді на запитання.

1.What is Internet?

2.Is there any difference between Internet and WWW?

3.What purpose was the Internet designed?

4.What does the infrastructure of the Internet consist of?

5.What does the Internet protocol serve for?

Факультет радіо приладобудування

TELECOMMUNICATIONS Telecommunication is the transmission of messages, over

significant distances, for the purpose of communication. In the modern age of electricity and electronics, telecommunications has typically involved the use of electric means such as the telegraph, the telephone, and the teletype, the use of microwave communications, the use of fiber optics and their associated electronics, and/or the use of the Internet. The first breakthrough into modern electrical telecommunications came with the development of the telegraph during the 1830s and 1840s.

A revolution in wireless telecommunications began in the first decade of the 20th Century, with Guglielmo Marconi winning the Nobel Prize in Physics in 1909 for his pioneering developments in wireless radio communications.

Communications signals can be either by analog signals or digital signals. These are analog communication systems and digital communication systems. For an analog signal, the signal is varied continuously with respect to the information. In a digital signal, the information is encoded as a set of discrete values (for example, a set of ones and zeros). During the propagation and reception, the information contained in analog signals will inevitably be degraded by undersirable physical noise.

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A basic telecommunication system consists of three primary units that are always present in some form:

-a transmitter that takes information and converts it to a signal;

-a transmission medium, also called the "physical channel" that carries the signal. An example of this is the "free space channel";

-a receiver that takes the signal from the channel and converts it back into usable information.

For example, in a radio broadcasting station the station's large power amplifier is the transmitter; and the broadcasting antenna is the interface between the power amplifier and the "free space channel". The free space channel is the transmission medium; and the receiver's antenna is the interface between the free space channel and the receiver. Next, the radio receiver is the destination of the radio signal, and this is where it is converted from electricity to sound for people to listen to.

Sometimes telecommunication systems are "duplex" (twoway) with a single box of electronics working as both a transmitter and a receiver, or a transceiver.

Дайте відповіді на запитання.

1.What is the purpose of telecommunication?

2.When did the era of telecommunication begin?

3.What is the difference between analog and digital signals?

4.What does a basic system consist of?

5.What is a duplex system?

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