Chapter 2 - Communication and Internet technologies

Question 1

What is simplex data transmission?

Answer 1

data transmission in one direction only

Question 2

What is half-duplex data transmission?

Answer 2

data transmission in two directions but not at the same time

Question 3

What is full-duplex data transmission?

Answer 3

data transmission in two directions at the same time

Question 4

What is serial transmission?

Answer 4

data sent one bit at a time over a singe wire or channel

Question 5

What is parallel transmission?

Answer 5

several bits of data sent down several wires/channels at the same time

Question 6

What is asynchronous transmission?

Answer 6

data being transmitted in an agreed bit pattern

Question 7

What is synchronous transmission?

Answer 7

a continuous stream of data which is accompanied by timing signals generated by an internal clock

Question 8

What is a Universal serial bus? (USB)

Answer 8

an asynchronous serial data transmission method which has become an industry standard

Question 9

What are the advantages of a USB?

Answer 9

the device is automatically detected
can only be entered one way around (prevents false connections)
device drivers are automatically loaded

Question 10

What are parity checks?

Answer 10

Allows us to see if any bits have been skewed in data transmission
can either be odd or even number of 1’s (parity complete with parity bit)

Question 11

What are Automatic repeat request (ARQ)?

Answer 11

Uses an acknowledgement to indicate data is received correctly
A timeout is used which is the time allowed to elapse before an acknowledgement is received

Question 12

What is checksum?

Answer 12

an additional value known as checksum is sent at teh end of the block of data
the checksum is based on the number of bytes in the block
if the checksum does not match on the receivers end, then an error has occoured

Question 13

What is an echo check?

Answer 13

the data is returned to the sender
the sender then compares the data received with the data sent
if they are different then an error in data transmission has occoured

Question 14

What is the issue with echo checks?

Answer 14

the data could become skewed when transferred back and not have been affected when sent to the receiver

Question 15

What is an ISP?

Answer 15

a company that provides the user with access to the internet - usually with a monthly fee
gives a user an account and email address

Question 16

What is an IP address?

Answer 16

an address which each device is given when connecting to the internet - will be different each time the device connects

Question 17

What is a MAC address?

Answer 17

uniquely idenitifies a devic connected to the internet - the MAC address does not change but can be LAA or UAA

Question 18

What is structure in HTML?

Answer 18

an essential part of HTML documents: includes semantics and structural mark ups of the documents

Question 19

What is presentation in HTML?

Answer 19

the style of the document: how the document will appear on a user’s computer screen

Question 20

What is http?

Answer 20

a set of rules which must be obeyed when transferring files over the internet

Question 21

What is a web browser?

Answer 21

software which allows a user to display a web page on the computer screen - it interprets/translates the HTML from the website and shows the result