Data Transmission

Question 1

Serial Transmission

Answer 1

Bits are sent one after the other over a single wire from source to destination.

Question 2

Parallel Transmission

Answer 2

Multiple bits are sent simultaneously over parallel wires from source to destination.

Question 3

Uses of serial transmission

Answer 3

Transmission to another computer or external devices, Medium to long distances, Universal Serial Bus

Question 4

Uses of parallel transmission

Answer 4

Fast transmission within a computer system, Short distances, Integrated Circuits (IC), Busses

Question 5

Problem with parallel transmission

Answer 5

Bits could travel at slightly different speeds over each of the wires. This produces a problem known as data skew.

Question 6

Advantages of serial over parallel transmission

Answer 6

Parallel wires are unreliable over long distances. Serial is reliable over long distances
Serial transmission tends to be cheaper.
Parallel wires suffer from ‘crosstalk’, which is interference between different lines that can result in data corruption.
Serial transmission suffers from little interference at high frequencies, therefore the signal frequency can be much higher than parallel transmission. This results in higher net data transfers rates.

Question 7

Simplex

Answer 7

When data transmission can only take place in one direction. e.g. Tv remote

Question 8

Half duplex

Answer 8

Communication can happen in both directions but not at the same time. e.g. Walkie talkie

Question 9

Duplex

Answer 9

Communication takes place in both directions at the same time. e.g. Phone call

Question 10

Multiplexing

Answer 10

Several independent data sources are combined to be sent along a single route to a specific destination.

Question 11

In packet switching

Answer 11

Data is split into packets, each packet may be transmitted through different routes, packets may arrive out of order and therefore will be reassembled.

Question 12

In circuit switching

Answer 12

A path is set up between the sender and receiver, all data follows the same path, in order one after the other. That path cannot be used by any other data until it is finished.

Question 13

Advantages of packet switching

Answer 13

Better security as it is very difficult to intercept packets on different routes.
Makes more efficient use of data lines as there is no waiting during gaps.
Less likely to be affected by network failures.