Data transmission

Question 1

Serial transmission -

Answer 1

• data bits are sent one at a time down one cable
• very high data speeds can be achieved
• used with USB interface

Question 2

What does USB stand for

Answer 2

Universal Serial Bus

Question 3

Parallel transmission -

Answer 3

several bits sent simultaneously
- faster the serial transmission but can only be used over very short distances

Question 4

What is parallel transmission used with

Answer 4

• printer cables
• internal devise connections

Question 5

Pros of serial transmission

Answer 5

• lower interference
• more reliable over longer distances
• smaller, simpler and cheaper connections to produce

Question 6

Cons of serial transmission

Answer 6

Lower transmission speeds

Question 7

Pros of parallel transmission

Answer 7

• very fast data transfer
• can send data in both directions at the same time

Question 8

Cons of parallel transmission

Answer 8

• interference issues between wires
• data corruption can occur over long distances
• data bits traveling parallel to each other can move at different speeds causing them to arrive out of sync - skewing

Question 9

What is skew

Answer 9

• each wire in a parallel cable has slightly different properties
• signals arrive at slightly different times
• receiver must wait until all lines are received until next set of bits mat be sent
• transmission needs to be over very short distances to reduce problem

Question 10

What is Crosstalk and when does it occur?

Answer 10

• occurs when a signal on one line creates a disturbance in another line
• may cause a line to be reversed in a parallel lines
• longer cables have more chance of interference
• buts in adjacent and neighboring wire in parallel transmission flips from 0 to 1 or 1 to 0 due to disturbance

Question 11

Benefits of USB

Answer 11

• USB cables can be connected to lots of difference devices - universal industrial standard
• a range of data transmission speeds is supported
• connector can only be inserted the correct way round

Question 12

Serial, simplex transmission -

Answer 12

• data sent in one direction only with one bit at a time sequentially across a single wire

Question 13

Where is simplex transmission used?

Answer 13

Serial : keyboard, mouse
Sending data from computer to monitor, doesn’t need to go the other way back

Question 14

Half-duplex transmission

Answer 14

Sending data in both directions but only one direction at a time, not simultaneously

Question 15

Where is half-duplex transmission used?

Answer 15

• parallel printer cables: text sent to a printer, and printer can send ‘out of paper’ messages back, but only when computer has finished sending text
• walkie talkie

Question 16

Duplex transmission -

Answer 16

data can travel in both directions simultaneously using tow communication channels

Question 17

Where are duplicates transmissions used?

Answer 17

• video conferences
• networking
• internet Cannes to transmit and receive at the same times