ICT Networks

ByL: Calsey and Salma

Network Devices:


are devices that connect computers to telephone lines. The name comes from ‘modulate and demodulate’ because telephone lines use analog signals and computers use digital signals. They can be external, connected to the computer/laptop or internally an expansion slot.


connect 2 different parts of a LAN.


connects 2 or more networks together, most commonly a home network to an internet network. 


are devices that connect networks using different systems. There are different types of gateways that change protocols into different ones. Such as an email protocol get changed by a gateway into a standard format, then to its next destination.


are devices that connect multiple computers to make a LAN. The hub receives messages from the server and sends them to all the computers.


connect multiple computers to make a LAN like a hub. It acts like a hub, but is more ‘intelligent’ and is more secure. It is also more expensive.

Characteristics and Purposes of Common Network Environments:

The internet is a worldwide interconnection of computers and networks that use the protocol IP.

Uses of the internet:

Research and Homework Communication (E-mail, Blogs, Social networking sites, chats, forums)

Online Shopping

Leisure and Entertainment (Video games, listing to music, reading your hobbies, booking flights)

Exploring the world

Benefits of the Internet:

Always available

Vast range of information

Easy to contact people

Accuses to other cultures


Issues of the Internet:

Information Overload

Information can be biased

Information can be inaccurate

Offensive material

Phishing sites

Cyber bulling



The WWW is a part of the internet but it is much younger. The internet is 40 years old whereas

the World Wide Web is 20 years old.

It was developed at CERN, the world famous underground physics laboratory in Switzerland. By

Tim Berners-Lee in 1990

The Intranet is an internal website that is setup internally for companies and can be accessed by

employees for the purpose of standard documents or information and many items of information and


What we need to connect to the internet:

A smart phone or Computer

A wireless enabled Router if using WiFi

ADSL or cable modem

An Intranet service provider

Problems with with ICT networks:

Computers connected to networks have problems. These are

  • Hackers can get in
  • Tasks become VERY difficult when/if the network breaks
  • Viruses can get into you computer easily

Some drawbacks to a computer connecting to the internet are:

  • Personal information can be revealed
  • You have to be careful to avoid dangerous websites containing malware.

Identification needs:

What is Encryption?

Encryption is when data is scrambled in a way that only someone with a code or key can read it.

Encryption is the process of converting information into a form that is meaningless to anyone except

holders of a ‘key’

A person who gains unauthorized access to a computer system is often called a hacker.

Ways to prevent Hackers accusing your computer?

  • Make sure that a hacker cannot physically access any computer on your network (For example, make sure all office doors are locked)

  • The most common way to protect your computer’s data is by having user names and passwords
  • Some places have ID cards and Fingerprints reader or voice recognition systems.


A firewall is a software or device that’s between your computer/network/ WAN(where the hacker is)

Often we have data that is private or confidential. This data needs to be protected from being viewed

by unauthorized people. This is especially true if the data is to be sent via a public network such as The



Encryption has been used for centuries to protect secrets.

Military leaders as far back as roman times have used encryption to protect important messages sent to

their armies, messages that must be kept secret from the enemy.

If the messenger was caught by the enemy, the message, being encrypted, remained secret because they didn't know the code to decrypt it.

ICT applications and impact:

DATA HANDLING APPLICATIONS: Data needs to be handled for different companies, school work and medical files, so it is more easy and organized to have it all on a computer. Doing this is a way better idea, it saves LOTS of space. These applications are: address books, society records, sales records, school reports and DATABASES!!

MEASUREMENT APPLICATIONS: Sensors measure different things, like temperature. These sensors can be attached to computers and they can measure and record all the data collected for you. These are used for scientific experiments, weather stations, environmental monitoring and so on. It is, yet again, is easier and more organized to use.

CONTROL APPLICATIONS: Computer control means that a computer is part of a system. The computer is normally used to run the control program.A sensor is a device designed to measure some physical quantity in its environment. Like above.A normal PC has no way of affecting what is happening around it. It can’t turn on the lights, or make the room hotter. How do we change what is happening around us? We use our muscles to move things, press things, lift things, etc. (and we can also make sound using our voice).

A normal PC has no muscles, but we can give it some. In fact we can give it the ability to do lots of things by connecting a range of actuators to it…An actuator is a device, controlled by a computer, that can affect the real-world.Examples of actuators, and what they can do are...

  • Actuator Light bulb or LED- Creates light
  • Heater- Increases temperature
  • Cooling Unit- Decreases temperature
  • Motor- Spins things around
  • Pump- Pushes water / air through pipes
  • Buzzer / Bell / Siren- Creates noise

Many of the devices that we use in our everyday lives are controlled by small computers...

  • Washing machines
  • Air-conditioning systems
  • Programmable microwave ovens

If we look beyond our homes, we come across even more systems that operate automatically under the control of a computer...

  • Modern cars have engines, brakes, etc. that are managed and controlled by a computer
  • Most factory production lines are computer-controlled, manufacturing products with little or no human input
  • Traffic lights are switched on and off according to programs running on computers which manage traffic flow through cities

Of course, car engines, factories and traffic lights were not always computer-controlled. Before microprocessors even existed, car engines ran, factories produced goods and traffic lights changed.

MODELLING APPLICATIONS: Computer modelling systems are used for many things (cars, buildings and animations) by MANY people all over the world with different professionalism They are used to test a design for something to see if it will work, to predict what will happen if it doesn't work and train people to use that thing so they can't destroy it when it comes to actually using it.


John Leonard (2011). The IGCSE ICT Site. Retrieved March 2013, from http://www.igcseict.net/

Smore (n.d.). Smore - Design beautiful online flyers and publish instantly. Smore. Retrieved February 2013, from http://www.smore.com

Steve Copley (n.d.). IGCSE ICT - Home. IGCSE ICT. Retrieved February 2013, from http://www.igcseict.info/