Digital communication 1

Question 1

What are the two factors which affect the speed devices can transfer data

Answer 1

Bandwidth
Latency

Question 2

Define bandwidth

Answer 2

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

Question 3

How can higher bandwidth impact the user experience?

Answer 3

Uploads and downloads are made faster
It is possible to do things that require lots of data to be transferred within short periods of time such as multiplayer online gaming and high definition video streaming.

Question 4

How is streaming a video different from a downloading a video.

Answer 4

All of the data does not need to be downloaded before a video can start playing.
The data needed for the video isn’t permanently stored in you computer, but is instead temporarily stored on an area of memory known as a buffer and is cleared from the memory once the videos is stopped playing.

Question 5

What happens to the video being streamed, if the buffer needed to store its data is empty?

Answer 5

It will stop playing until the buffer is filled with the remaining data again- a term known as buffering.

Question 6

What must be done to prevent buffering?

Answer 6

Data must be downloaded into the buffer faster than the rate at which it is being emptied.

Question 7

What does it mean for a buffer to be empty in terms of streaming a video?

Answer 7

The data to play a portion of the video which was temporarily stored on the area of memory has now been deleted as the that portion has already been played.

Question 8

Define latency

Answer 8

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

Question 9

What is one way of identifying latency?

Answer 9

By pinging a domain

Question 10

Define ‘ping time’ -

Answer 10

The amount of time it takes for the packet of data which is sent from the computer to the server to make the return trip.

Question 11

Define domain

Answer 11

The name used to identify a web server.

Question 12

How will high latency impact the user experience when gaming. 2 ways.

Answer 12

When playing multiplayer online games, events in the game will lag.

the game will not seem responsive to user commands.

Question 13

How will high latency affect the user when watching live television?

Answer 13

High latency will result in a delay between the real time events and the video being received for playback.

Question 14

How does the transfer method affect the data transfer rate?

Answer 14

Some wired methods such as copper cables can carry more frequencies than other wireless methods which have to deal with a limited number of frequencies.
In other words cabled methods have more bandwidth available for the transfer of data than other wireless methods.

Question 15

What is something you must keep in mind when comparing the bandwidth or wired and wireless methods of data transfer.

Answer 15

Older wired methods have less bandwidth available than new wireless methods.

Question 16

How does interference occur?

Answer 16

When other electromagnetic signals disrupt or interfere with wired and wireless signals.

Question 17

List some devices from which interference can be caused.

Answer 17

Other wireless devices, wireless routers, and appliances emitting electromagnetic fields like fridges and microwaves.

Question 18

Can interference happen to both wired and wireless media

Answer 18

YES

Question 19

What is one way that interference to signals carried by cabled connections can be blocked.

Answer 19

By wrapping the wires in a thing layer of metal.

Question 20

Do blockages only affect wireless signals.

Answer 20

YES

Question 21

How do blockages affect wireless signals-

Answer 21

Furniture and walls reduce the strength of wireless signals- this reduces the available bandwidth.

Question 22

How does distance affect both wired and wireless media-

Answer 22

The strength of the signals of both wired and wireless media reduce if the distance it has to travel increases.

Question 22

How does distance affect both wired and wireless media-

Answer 22

The strength of the signals of both wired and wireless media reduce if the distance it has to travel increases.

Question 23

Define frequency-

Answer 23

The waveband at which a radio signal is transmitted.

Question 24

Define device to device communication-

Answer 24

When devices connect to each other directly using wired or wireless methods.

Question 24

Define device to device communication-

Answer 24

When devices connect to each other directly using wired or wireless methods.

Question 25

How can a game controller be connected to a games console and what’s its purpose-

Answer 25

Through blue tooth
to control the game.

Question 26

How can a camcorder be connected to a monitor and what’s its purpose?

Answer 26

Through HDMI
to operate as a security camera

Question 27

How can a smart phone be connected to a headphone and what’s its purpose.

Answer 27

Through Mini Jack
to play the songs on the smart phone on the headphone

Question 28

How can laptops be connected to an external hard drive and what’s its purpose?

Answer 28

Through USB cable
To transfer files

Question 29

How can a temperature sensor be connected to a air conditioner and what’s its purpose?

Answer 29

Through a wired method to automatically turn on the air conditioning when the temperature is too high.

Question 30

Define HDMI

Answer 30

High definition multimedia interface used to transmit video and audio data

Question 30

Define HDMI

Answer 30

High definition multimedia interface used to transmit video and audio data

Question 31

Define HDMI

Answer 31

High definition multimedia interface used to transmit video and audio data

Question 32

Define minijack

Answer 32

A plug and socket widely used for analogue audio signals in portable devices