Information transmission media

There are the following types of cables:

• Coaxial

• Twisted-Pair

Unshielded Twisted-Pair (UTP)

Shielded Twisted-Pair (STP)

• Fiber-Optic

1 . Coaxial cable is the kind of copper cable used by cable TV companies between the community antenna and user homes and businesses. It is also widely installed for use in business and corporation Ethernet and other types of local area network. Coaxial cable is called "coaxial" because it includes one physical channel that carries the signal surrounded by another concentric physical channel, both running along the same axis. The outer channel serves as a ground. There are two types of coaxial cables: thinnet (thin-wire Ethernet) and thicknet (standard Ethernet).

Thinnet is a flexible coaxial cable about 0.25-inch thick. It is used for short distance communication. Thinnet coaxial cable can carry a signal up to approximately 185 meters (or about 607 feet) before needing a repeater.

Thicknet is about 0.5-inch in diameter. Typically, thicknet is used as a backbone to connect several smaller thinnet based networks. Thicknet can carry a signal for 500 meters (about 1,640 feet) before needing a repeater.

2. Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. To reduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. For some business locations, twisted pair is enclosed in a shield that functions as a ground. This is known as shielded twisted pair (STP). Ordinary wire to the home is unshielded twisted pair (UTP).

3. Optical fiber (or "fiber optic") refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic wire or fiber. Optical fiber carries much more information than copper wire and is in general not subject to electromagnetic interference and the need to retransmit signals. Single mode fiber is used for longer distances; multimode fiber is used for shorter distances.

Ex.11 Work in pairs. Make up a sentence in Russian. Your partner translates it into English and visa versa.

Ex. 12 Translate into English:

1. Коаксиальный кабель называется коаксиальным потому что включает два физичских канала вдоль одной оси.

2. Внешний канал служит заземлением.

3. Thinnet – это гибкий коаксиальный кабель толщиной в 0.25 дюйма.

4. Витая пара соединяет компьютеры дома и на предприятиях с телефонными компаниями.

5. Многомодовое волокно используется на более короткие расстояния.

Lesson 18

Text A. Computing Network Components.

Text B. Network Topology.

Ex.1 Translate into Russian:

Wave, backbone, dedicated, arrangement, responsible, approximately, peer-to-peer, wire, reference, single-mode fiber, shield.

Ex.2 Translate into English:

Свойство, кольцо, защищать, запускать, принадлежать, маркер, искать, звезда, окружать, медный, внешний, ссылаться.

Ex.3 Fill in the blanks:

Networks are usually classified using three properties: _________, _________, and _________. Topology specifies the geometric ________ of the network. Common topologies are a ________, _________, and _________. Protocol specifies a common set of _________ and _________ the computers on the network use to communicate. Most networks use _________, but some networks may use IBM's _________ _________ protocol. Architecture refers to one of the two major types of network architecture: _________and client/server (or server-based ). Sometimes they are used in _________.

Ex.4 Read and memorize the following words:

1. weak [wi:k] – слабый

2. (to) amplify [´æmplıfaı] - усиливать

3. traffic [´træfık] – трафик, поток обмена, рабочая нагрузка

4. amount [Ə´maunt] – количество

5. bottleneck [´bɔtlnek] – критический элемент, критический параметр, “узкое место” в системе

6. excessive [ık´sesıv] – излишний, чрезмерный

7. route [ru:t] – путь, маршрут, направлять

router - машрутизатор

8. (to) forward [´fɔ:wƏd] – передавать, ретранслировать

9. brouter [´bru:tƏ] – мост-машрутизатор

10. internetworking – организация сети, объединение сети, межсетевое взаимодействие

11. (to) deliver [dı´lıvƏ] – (пре)доставлять

12. gateway [´ɡeıtweı] – шлюз

13. (to) arrive [Ə´raıv] – прибывать

14. audible [´ɔ:dƏbl] – акустический, звуковой

15. (to) decide [dı´saıd] – решать

decision [dı´sıʒn] - решение

16. destination [ˏdestı´neıʃn] – место назначения, адресат, пункт назначения

17. average [´ævƏrıʤ] - средний

by an average – в среднем

18. protocol stack – стек (набор) протоколов

19. external [ek´stƏ:nƏl] – внешний

20. trunk [trʌnk] – магистраль

21. detect [dı´tekt] – обнаруживать, находить

error detection – обнаружение ошибок

22. loop [lu:p] – кольцо, петля, цикл

23. (data) throughput [´θru:put] – пропускная способность

24. (to) match [mæʧ] – подходить, соответствовать

25. verification [ˏverıfı´keıʃn] – верификация, проверка, контроль

Ex.5 Read and translate into Russian: