2. Hardware

You are probably reading this from a school computer. But how do you connect to the Internet from home or a company?

Once you have your computer switched on, you need a MODEM to connect your computer to the telephone line in your house.

A modem (short for MODulator/DEModulator) converts your computer's digital signal into an analogue signal which the telephone line can deal with. It then converts analogue data coming down the telephone line into digital data for your computer to use.

Most of you will probably have broadband or ADSL connections by now, although in the past people used to have very slow dial-up connections.

You will also need a method of getting the data from your computer to the Internet. This is usually via the telephone network. However, some people connect to the Internet using satellites, fibre-optic cables or radio waves (Wi-Fi).

Not that long ago, computers were the only devices that most people could use to connect to the internet. However, over the last few years, smart phones, tablet computers, PDAs, e-book readers and many other devices are now Internet enabled.

Many people can even connect to the Internet via their television.

On a local area network (LAN) many computer workstations can connect to the Internet (your school for example), but they do not all have to have a modem. Instead each workstation will send requests over the LAN and through a 'firewall'.

A firewall examines each data request and each piece of downloaded data to make sure it is allowed by the school. If the data is not allowed, then the data is discarded. For example, some malware may be trying to get in from a rogue web site, but the firewall will try to prevent it getting through. A firewall can be a pure software application but more serious firewalls are pieces of equipment sitting in the server room.

There is a modem on the other side of the firewall that connects the school to the Internet.