Communication

Question 1

serial data transmission

Answer 1

Method of data transmission
each bit is sent one after another
over a single wire

Question 2

parallel data transmission

Answer 2

Method of data transmission
Multiple bits (often 8 bits) sent at the same time
over multiple wires

Question 3

advantages of serial transmission

Answer 3

more accurate/fewer errors over a longer distance
less expensive wiring (single wire)
less chance of data being skewed/out of synchronisation

Question 4

disadvantages of serial transmission

Answer 4

slower- less data sent at once due to only one wire

Question 5

advantages of parallel transmission

Answer 5

faster, more data sent at once due to more wires

Question 6

disadvantages of parallel transmission

Answer 6

less accurate/more errors over a longer distance
more expensive wiring (multiple wires)
more chance of data being skewed/out of synchronisation

Question 7

serial transmission use

Answer 7

Medium to long distances

Ethernet
Telephone Wire
USB (Universal Serial Bus)

Question 8

parallel transmission use

Answer 8

Short distances

Fast internal data transfer within a computer system (buses)
IC’s (Integrated Circuits)
Older printers

Question 9

synchronous transmission

Answer 9

A continuous stream of data
The data is accompanied by timing signals (generated by an internal clock)
The clock ensures the sender and receiver are in step with each other

Question 10

asynchronous transmission

Answer 10

Data is transmitted in discrete packets (usually 1 byte)
Each packet of data is sent with control bits
The control bits allow the receiver to know when the data starts and ends
The control bits prevent the packets of data getting mixed up
Packets are sent intermittently (they have uneven time intervals between them

Question 11

duplex data transmission

Answer 11

Direction of data transmission is both ways at the same time (simultaneously)

Question 12

half-duplex data transmission

Answer 12

Direction of data transmission is both ways but not at the same time (not simultaneously)

Question 13

simplex data transmission

Answer 13

Direction of data transmission is one way only (unidirectional)

Question 14

duplex data transmission example

Answer 14

Telephone call

broadband connections video conferencing

Question 15

half-duplex data transmission example

Answer 15

Walkie Talkie

Intercom

Question 16

simplex data transmission example

Answer 16

radio/tv broadcast
microphone to computer
computer to speaker

Question 17

Integrated Circuits

Answer 17

self-contained circuits with many separate components (e.g. transistors, diodes) etched into a tiny silicon chip

Uses parallel transmission for sending data internally in computer systems

Question 18

Disadvantages of integrated circuits

Answer 18

Less flexible -components cannot be removed or replaced so whole IC must be
Limited power rating

Question 19

Advantages of integrated circuits

Answer 19

Small size – thousands times smaller than discrete circuits
Small weight due to miniaturised circuit
Low cost due to mass production
Low power consumption because of their smaller size

Question 20

USB

Answer 20

Universal Serial Bus

Uses asynchronous serial transmission for sending data externally to and from peripherals / between devices

Question 21

Advantages of USB

Answer 21

Devices plugged into the computer are automatically detected
The connectors can only fit one way- prevents incorrect connections being made
Industry standard-considerable support is available to users
Supported by many operating systems

Question 22

USB device is plugged into a computer

Answer 22

The computer automatically detects a device (due to a small change in the voltage level)
A known device is automatically recognised, and the appropriate device driver is loaded
If a new device is detected, the computer will look for and install the device driver
If this is not available, the user is prompted to download the device driver

Question 23

Disadvantages of USB

Answer 23

limited distance

current transmission rate is slower than ethernet