2.03 - Transmission media

Question 1

What are the 3 types of network cables?

Answer 1

1. Twisted pair cable
2. Coaxial cable
3. Fibre - optic cable

Question 2

Which cable costs the most?

Answer 2

Fibre optic cable

Question 3

Which cable costs the least?

Answer 3

Twisted pair cable

Question 4

Which cable has the highest bandwidth?

Answer 4

Fibre optic cable

Question 5

Which cable has the least bandwidth?

Answer 5

Twisted pair cable

Question 6

Which cable is most affected by attenuation?

Answer 6

Coaxial cable

Question 7

Which cable is least affected by attenuation?

Answer 7

Fibre optic

Question 8

Which cable is most affected by interference?

Answer 8

Twisted pair cable

Question 9

Which cable is least affected by interference?

Answer 9

Fibre optic cable

Question 10

Which cables need repeaters often?

Answer 10

Twisted pair and Coaxial cables

Question 11

Which cable need repeaters less often?

Answer 11

Fibre optic

Question 12

Name

A simmilarity between Coaxial and Twisted pair cables

Answer 12

Both use copper for transmission medium

Question 13

Name

Factors to consider when choosing a cable for a given application

Answer 13

1. Cost of cables and connecting devices
2. Bandwidth
3. Attenuation
4. Interference
5. Need for repeaters

Question 14

Which 2 factor effect performance during transmission throgh cables?

Answer 14

Attenuation and Intereference

Question 15

What are the 3 types of wireless transmission?

Answer 15

1. Radio waves
2. Microwaves
3. Infrared / Satellites

Question 16

Name

Frequencies of radiowaves, microwaves and infrared

Answer 16

Radio waves (3KHz-3GHz)
Microwaves (3-300GHz)
Infrared (300GHz-400THz)

Question 17

Use of twisted pair cables?

Answer 17

Used for high speed LANs and connecting telephone handsets to telephone lines

Question 18

Which cable can either be shielded or unshielded?

Answer 18

Twisted pair cable

Shielding affects the use of cable

Question 19

Use of Coaxial cable?

Answer 19

Used in cable television companies and in MANs

Question 20

Use of Fibre optic cables?

Answer 20

Long distance cabling

Question 21

Name

The layers of the Coaxile cable (from out to in)

Answer 21

1st - Plastic jacket
2nd - Metallic shield
3rd - Dielectric insulaltor
4th - centre core

Question 22

Name

Factors, apart from the cable ones, needed to consider when choosing wireless transmission

Answer 22

1. Ability to transmit through solid barriers
2. Ability to focus transmission in a specific direction

Question 23

Which wireless transmission has the greatest ability to transmit through solid bariers?

Answer 23

Radiowaves

Question 24

Which wireless transmission has the highest bandwidth and why?

Answer 24

Infrared due to high frequency

Question 25

Which wireless transmission is mostly affected by attenuation?

Answer 25

Infrared

Question 26

Which wireless transmission is best for indoors?Why?

Answer 26

Infrared. Because of the increased attenuation during transmission and the transmission cannot escape through the walls and cause unwanted interference

Question 27

Which transmission needs government permission to use?

Answer 27

The use of certain wireless transmission media is regulated by government agencies therefore requires permission

Question 28

# Name A disadvantage of using cables that relate to getting permission.

Answer 28

Cables can only be laid in the ground with the permission of the land lord

Question 29

For global communications, which wired and wireless transmission is used?

Answer 29

Wired - Fibre optic underground / under the sea bed Wireless - satellites

Question 30

# Name Disadvantages of using Wireless data transmission

Answer 30

1. The use of certain wireless transmission frequencies is regulated by government agencies, therefore permission is required to use it 2. Interference is much more significant and its extent is dependent on which frequencies are used for different applications

Question 31

# Name Advantages of using Wireless data transmission

Answer 31

1. Repeaters are needed less often for wireless transmission 2. Mobile phones now dominate Internet use and for these, only wireless can be used 3. For home or office, both are equally efficient although not having to add cables favours wireless

Question 32

# Name Disadvantages of using wired data transmission

Answer 32

1. Cables can only be laid in the ground with the permission of the landlords 2. For home or office, both are equally efficient although not having to add cables favours wireless

Question 33

What are satellites?

Answer 33

Satellities are components of mordern communication systems and can directly connect with ground-base components

Question 34

What are the Van Allen Belts?

Answer 34

Van Allen Belts are areas containing high levels of electrically chargered particles particles, which interfere with satellites

Question 35

What are the three tyes of Van Allen Belts?

Answer 35

1. GEO 2. MEO 3. LEO

Question 36

Define GEO

Answer 36

Geo (Geostationary Earth Orbit) - The highest altitude over the equator and these are used to provide long-distance telephone and computer network communications. | (Only three of these are needed for full global coverage)

Question 37

Define MEO

Answer 37

MEO (Medium Earth Orbit) - Closer to Earth and provide the Global Positioning System (GPS) | (10 for global coverage)

Question 38

Define LEO

Answer 38

LEO (Low Earth Orbit) - Work in constellations to supplement mobile phone networks | (50 for global coverage but currently there are several 100)

Question 39

What does Geostationary mean?

Answer 39

‘Geostationary’ means that the satellite orbits at the same speed as the Earth spins, therefore from a point on Earth the satellite always appears to be at the same place in the sky

Question 40

Why can satellites cause transmission delays?

Answer 40

Satellites can cause transmission delays due to their greater distance from the Earth's surface.

Question 41

Why has Fibre optic cabling reduced the need for satellites?

Answer 41

Fibre-optic cabling has reduced the need for satellites in Internet communication due to lower costs.