Chapter_4_(Digital_communication)

Question 1

What does the speed at which devices can transfer data depend on?

Answer 1

It depends on the bandwidth of the connection.

Question 2

What is bandwidth?

Answer 2

The number of bits that can be carried by the connection in one second.

Question 3

What does higher bandwidth mean?

Answer 3

Higher bandwidth means more data can be transferred every second, making download and uploads faster.

Question 4

What is buffer?

Answer 4

An area of memory used to temporarily store data, especially in video streaming.

Question 5

What happen if the buffer is empty when playing a video?

Answer 5

There will no more videos to play and it will pause until more data is downloaded.

Question 6

How to avoid the buffer becoming empty?

Answer 6

Data must be downloaded into the buffer constantly, filling it up at a rate faster than it is emptied.

Question 7

How can you identify the latency?

Answer 7

By pinging a domain

Question 8

What is latency?

Answer 8

The amount of time it takes to send data between devices.

Question 9

What is domain?

Answer 9

The name used to identify the web server.

Question 10

Wireless method has to work on an unlimited amount of frequency.

Answer 10

False

Question 11

Which carry more frequencies, copper cable or wireless method?

Answer 11

Copper cables

Question 12

What interfere with wired and wireless signals?

Answer 12

Other electromagnetic signals

Question 13

How can cabled connection be done to prevent interference?

Answer 13

They can be shielded.

Question 14

What reduce the available bandwidth of wireless signals?

Answer 14

Walls and furniture reduce the strength of wireless signals.

Question 15

What reduce the strength of wired and wireless signals?

Answer 15

The more distance reduce the strength of wired or wireless signals.

Question 16

What is LAN?

Answer 16

LAN is a network that connects digital devices that are in a small geographical area.

Question 17

What is WAN?

Answer 17

WAN is a network that is spread over a large geographical area.

Question 18

What does WANs use?

Answer 18

It often use connectivity provided by a third party telecommunications company, often linking LANs together through the internet.

Question 19

WANs have _____ transfer speeds than LANs.

Answer 19

Slower

Question 20

What is PAN and WPAN?

Answer 20

PANs is a group of connected devices that are all near an individual user.

WPAN (Wireless Personal Area Network)

Question 21

What is tethering?

Answer 21

Tethering is connecting a host device that uses a mobile broadband connection with other devices, so that they can use the host’s broadband connection.

Question 22

What are some common methods that digital devices use to share data?

Answer 22

• Satellite
• Broadcast
• Wired
• Wireless

Question 23

What does digital devices use to receive radio signals that satellites transmit?

Answer 23

Antenna

Question 24

What are the benefits and disadvantage of satellite communication?

Answer 24

• It has number of satellites meaning the system is always available and can’t be affected by power shortages
• Satellite signals does not pass through solid objects meaning they might not be available in some places

Question 25

Which communication does GPS use?

Answer 25

Satellite communication

Question 26

From where do GPS signals send from and how many satellites is required to calculate the accurate location of digital device?

Answer 26

GPS signals are sent from a network of 24 satellites orbiting the earth and only four is required to calculate the accurate location.

Question 27

What is DVB?

Answer 27

Digital video broadcasting is the internationally accepted standard method of broadcasting digital television.

Question 28

What is DVB-S?

Answer 28

Digital video broadcasting satellite is a type of DVB which a video signals from broadcaster is transmitted using a large antenna on earth to one or more satellites which thenbroadcasted signals back to earth, received by antenna.

Question 29

What decodes the signals received from satellite and send it to television?

Answer 29

set-top box

Question 30

What are other things that satellite communication allows?

Answer 30

It is used for people in remote areas to place voice calls using satellite telephones.

Question 31

What broadcast television and radio signals that are received by viewer's antenna?

Answer 31

Transmitter

Question 32

What is DVB-T?

Answer 32

Digital video broadcasting (terrestrial) is a method of DVB where transmitters are based on earth, rather than in orbit as they are in DVB-S.

Question 33

What is DVB-T2?

Answer 33

DVB-T2 is a newer standard that provides more functionality, such as HDTV and interactive services.

Question 34

What is DAB?

Answer 34

Digital Audio Broadcasting which is broadcast in the same way as DVB, and it provides more radio stations and can also carry text data that DAB receivers can display.

Question 35

What is ethernet?

Answer 35

A network connectivity standard that provides a way for computers to communicate.

Question 36

What are the connection types and their uses?

Answer 36

- HDMI - digital video connections - S/PDIF - Digital audio connections - Minijack - Personal headphones - USB - Storage transfer - Ethernet - networking

Question 37

What does ethernets allow?

Answer 37

It allow user to connect to wired networkers?

Question 38

What is the maximum length of ethernet cable which can carry signals without lose of quality?

Answer 38

100meters

Question 39

What is WI-FI?

Answer 39

Wi-Fi is a wireless technology used to connect devices to a network which are connected to the internet.

Question 40

Which specification of standards does Wi-Fi for wireless communications?

Answer 40

IEEE 802.11

Question 41

What is Bluetooth?

Answer 41

Bluetooth is a type of wireless connectivity that lets devices connect over short distance.

Question 42

Which can carry more data Wi-Fi or Bluetooth?

Answer 42

Wi-Fi

Question 43

What is Bluetooth used?

Answer 43

It is used to transfer small files between devices.

Question 44

What are difference between Wi-Fi and bluetooth?

Answer 44

- Wi-Fi has long range - Wi-Fi has higher bandwidth - Wi-Fi has higher power consumption - Wi-FI has higher security - Wi-Fi can connection multiple simultaneously while Bluetooth is limited

Question 45

What are 3G and 4G used?

Answer 45

They are used to provide internet access to mobile devices.

Question 46

What does G in 3G and 4G stands for?

Answer 46

Generation

Question 47

What does Infra-red transmitters should have?

Answer 47

It must have a clear line of sight to receivers because this allows signal to travel in a straight line between them?

Question 48

What does NFC (near field communication) use?

Answer 48

It use close proximity RFID chips.

Question 49

What are the advantages and disadvantages of Wired and wireless connectivity?

Answer 49

Wired - Cables are cheap for small number - Risk of tripping over cables - Faster than wireless - Less affected by interference than wireless - Not portable and may need signal booster - Can look untidy - Most secure - Using cables and ports long time may damage them Wireless - may need wireless access point - Slower than wired - Affected by obstacles - Portable within signal range - Tidy - Less secured

Question 50

What is ISP?

Answer 50

A company that provides customers with access to the internet. (internet service provider)

Question 51

What does ISP use?

Answer 51

Fibre optic cable or copper cable network

Question 52

What does mobile broadband provide?

Answer 52

High-speed wireless connectivity using 3G or 4G