Standard Grade Computing Studies
Communications and Networks
Frank Frame
Computing Studies
Standard Grade
Communications and Networks
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Acknowledgement
Thanks to Dorothy Tedman for her contribution to the review of the content.
First published 2004
This publication may be reproduced in whole or in part for educational purposes by
schools and colleges in Scotland provided that no profit accrues at any stage.
ISBN 1 84399 036 9
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Contents
Introduction
4
What is a Network?
5
Local Area Networks
5
Wide Area Networks
8
Multi-access Computers
9
Security on Networks
10
Electronic Communication
11
The Internet
14
Network and Communications Questions
28
Networks: Answers to Questions
32
Answers to Exercises
36
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Introduction
This publication is part of a series of publications to support Standard Grade
Arrangements in Computing Studies (March 2004). The titles in the series are:





General Purpose Packages
Communications and Networks
Computer Systems
Automated Systems
Commercial Data Processing.
The first two packs, General Purpose Packages and Communications and Networks,
provide complete coverage of the content as specified in the updated arrangements for
Standard Grade Computing Studies.
The other three packs, Computer Systems, Automated Systems, and Commercial Data
Processing have been produced to support the three programmes featured on the DVD.
The content of these materials has been written to relate directly to the programmes on
the DVD and may not cover all the content as specified in the course arrangements.
Communications and Networks
The materials contained in this pack support the section on communications and
networks. They contain student notes, exercises, questions and answers at Foundation,
General and Credit level covering all the content as specified in the course
arrangements.
Note: Credit level is marked in this document with shading.
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What is a Network?
A network is a series of computers linked together so that they can send and receive
data. We use networks for all sorts of things such as sending e-mails, sharing and
downloading files, shopping and doing our banking.
We can divide networks up into two types: Local Area Networks (LANs) and Wide Area
Networks (WANs).
Local Area Networks
Local Area Networks (LANs) operate in one area, such as an office block, a factory or a
bank. You may even have a small LAN at home. The computers are joined together using
cables or wireless transmitters.
Most schools, factories, universities and businesses have their own LAN.
The advantages of LANs are that:

users can share peripherals such as hard drives,
printers, and web cameras

users can share data files such as database
files, standard letters and multimedia
presentations

they make it easy to communicate by sending
e-mails.
Exercise 1
1. Write a list of four businesses or organisations that use LAN.
2. Your teacher wants every member of your class to get a copy of a word
processing document and correct the spelling mistakes. How could the LAN
help?
3. You decide to get involved in producing a newsletter for your year group and
need some help putting it together. How could the LAN help you get other
people interested?
4. List the advantages of using a LAN.
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Transmission media
To connect computers together and transmit data LANs use either cables or wireless
transmission.
Cables
You need to know about the two main types of media: copper cabling and fibre-optic
cabling.
Copper cabling
There are two main types of copper cabling used in LANs:

Coaxial cabling – This is cabling where the central cable that transmits the data is
surrounded by a shield of copper braiding. This protects it from interference and so
coaxial cabling is found in networks in places such as factories where there is a lot
of possible interference.

Twisted-pair cabling – This type of cabling is used in lots of LANs. It is probably in
use in your school network. It is a simple type of cabling made up of two copper
cables. It is relatively cheap and can support quite high transmission speeds, for
example over 100 Mbits per second.
Fibre-optic
Fibre-optic cable is made up of fine strands of glass that carry pulses of light. These
pulses of light represent data being transmitted.
The advantages of fibre-optic cable are that it:



is more difficult to break into the cable and so is more secure
does not suffer from electro-magnetic interference
transmits at high speeds.
One disadvantage is that it costs more to buy and install than other types of cabling.
Wireless networking
Some networks use wireless
connections to transmit their data.
Wireless networking transmits data
through the air using radio waves and
microwave frequency radiation.
The advantages of this approach are
that:
 a wireless network is relatively easy
to install, all you need is a
transmitter/receiver and a wireless
Network Interface Card on each
computer on the network
 there is no need for any wiring
 transmission speeds are very fast.
The disadvantage is that security can be a problem because wireless networks are relatively
easy to hack into.
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Why do you need a Network Interface Car to connect
your computer to a LAN?
A NIC carries out tasks that are vital to connect your computer to a network.

It take the data sent by your computer on to the
network, stores it in its own memory locations and then
adapts it to make sure that it follows the communication
rules that govern the network.

It takes data coming in from the network to your
computer and passes it on to the processor.
Every device that is connected to the LAN will need a NIC, for example, computer, printer
and scanner.
What are client/server networks?
Lots of networks are set up as client/server networks. A client is a workstation on the
network. A server is central to this set up. It is a computer that has a fast processor and
lots of memory and is used to control the resources that the client workstations can use. A
server can be used for a whole range of tasks. It might be:
 organising the printing on a network
 holding all the data files or the applications software
 organising the clients’ access to the internet.
The server lets the user at a computer system or workstation attached to the network use
the resources it controls: it
lets the client print, access
the internet and update a
database file.
Exercise 2
1.
2.
3.
4.
5.
List two commonly used types of network cable
Why is wireless networking becoming popular?
Why do computers that are attached to a LAN need a NIC?
What is the key role of a server on a client/server network?
What is a client?
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Wide Area Networks
Wide Area Networks (WANs) connect computers across large distances. WANs stretch
across towns, link up cities such as Aberdeen and London, and spread across countries
worldwide using telecommunications links.
The advantages of WANs are that:
 people can communicate instantly worldwide
 they can be used to:
- send e-mail
- send data files
- carry out financial transactions
- work from home and still be in contact
with the central office
- access information
- carry out research
 WANs are central to the success of large
businesses.
Exercise 3
Complete this table comparing a LAN and a WAN.
LAN
WAN
Distance covered
Means of linking computers
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Multi-access Computers
These are powerful computer systems that enable many users to:
 access the system at the same time
 share the processing power of the
system
 share the available memory
 share the data on the backing storage.
Multi-access computers have many
terminals attached to them. These
terminals are made up of keyboards and
monitors that people use to:
 interact with the main processor
 load data to and from backing storage
 display data held on the system.
They key point about these terminals is that they have little or no local processing or
memory, and are merely used to access the processing power available on the
central powerful computer system.
How does a multi-access computer work?
It gives each terminal a slice of the processor’s time. It goes round the users very
quickly, so quickly that they are not aware that they are sharing the system with lots
of other people.
Where do you find multi-access computers?
Large organisations such as banks, insurance companies and mail order companies
as well as colleges and universities use them to store and process their data.
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Security on Networks
All networks need to have security measures in place. If they
do not then the network can be hacked into, data deleted,
copied or changed.
We can divide security measures up into two categories:
physical security measures that can prevent unauthorised
people accessing the network hardware, and software
security measures that can prevent unauthorised access to
the system and the data it holds.
Physical security measures



Installing network computers with a lock that has to be opened before people
can even log on.
Using security locks on the rooms where the computers are stored.
Installing network computers that have no floppy disk drives or CD-drives.
Software security measures

User identities (IDs) and passwords
– Only authorised users are issued with the IDs and passwords that are
needed to gain entry to the network.
– When users log on, the computer system checks their IDs and
passwords and tries to match them with those that it keeps on file.
– They are only allowed on to the


network if the IDs and
passwords they have entered
match those kept on the system.
Advanced ID measures
– Some systems use biometric
systems to ID authorised
users. That means they
store data about fingerprints,
voices or people’s eyes on
special smart cards.
Encryption: encoding the data held on the system.
– This means that if the network is hacked into then the data is meaningless to the
hacker.
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Exercise 4
1. List the physical security measures that can be used to protect a network.
2. How does the ID and password system work?
3. What are the advanced ID security measures that can be used to protect computer
networks?
4. How does encryption protect the data held on a network?
5. Why is it so important to back up data held on a network?
6. What is the difference between a network and a multi-access computer?
7. What are the types of businesses and organisations that use multi-access systems?
Electronic Communication
There are two ways of communicating electronically: by text messaging and by e-mail.
Text messaging
One form of text messaging is ‘instant messaging’ that allows you to send text messages
to people on their PCs. You log on to the messaging server and send messages to your
group. Some messaging services such as MSN explorer even let you talk to your group
using a microphone.
Another type of text messaging lets you send short text messages to a maximum of 160
characters. These are stored on central computer systems and then forwarded to pagers,
mobile phones and palmtop computers with mobile phone connections.
Electronic-mail (e-mail)
We use e-mail to send messages to people
anywhere in the world. E-mail gives us
instant communication and enables us to
contact people quickly and at little cost.
What are the advantages of e-mail?

E-mail delivery is very fast, especially when compared to ordinary mail delivered by
the postman. E-mail takes seconds or perhaps minutes, not days, to arrive at its
destination.

It costs a lot less than surface mail. Most e-mail services are free to the
user, the main cost being the cost of your telecommunications link.
If you use web-based e-mail you can check your inbox any time you
want, from anywhere in the world where there is an internet connection.
E-mail software lets you send multiple copies so you can send the same
message to several of your friends at one time.
Your e-mail is secure because you need an ID and password to access it.



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Can e-mail cause you problems?


Viruses can be hidden in e-mail attachments, so you must be careful and avoid
opening attachments from people you do not know.
Lots of ‘spam’ arrives by e-mail. Spam is unwanted adverts, special offers and
general ‘junk mail’.
Using e-mail to transfer files across the Internet
If you want to send someone a data file, the easiest way is to send it by attaching it to
an e-mail message. Setting up an attachment is easy. Once you have written your email message all you have to do is browse your hard drive and select the file you want
to attach.
Are they any problems involved in sending files as e-mail with
attachments?
Some e-mail providers do put limits on the size of files that can be attached to e-mails.
Some people use e-mail attachments to send viruses around networks. So you must
be careful not to open unexpected attachments.
Using netiquette
Netiquette is a set of rules that governs the way people behave when using email, or a
network. You can find different versions of netiquette code but it is important to realise
that they are all trying to do the same thing: set down codes of conduct for behaviour
on the network.
Here is a sample of a netiquette code.
1.
2.
3.
4.
Do not start flame wars.
Do not use bad language, always be polite.
Do not post unwanted mail or use e-mail to spam.
Be patient with people who use e-mail to ask awkward questions.
Discussion points: Are these good rules? What are the reasons for having these rules?
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Exercise 5
1.
2.
3.
4.
List three reasons why e-mail is so popular?
Describe how e-mail can be used for ‘spamming’.
How is text messaging different from e-mail?
Copy out and complete the netiquette code in the table below, adding
reasons for each item in the code.
Netiquette code item
Reason
Do not start flame wars.
Using e-mail to start an argument can
quickly get out of control and offend a
lot of people…
Do not use bad language, always be
polite.
Do not post unwanted mail or use
e-mail to spam.
Be patient with people who use e-mail
to ask awkward questions.
5. Search the internet for a netiquette code and print out a copy.
6. Why are e-mail attachments so useful?
7. Outline any problems that might occur with the use of e-mail attachments.
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The Internet
What is the internet?
The internet is a system that enables computers and networks worldwide to connect
with each other using a range of telecommunications systems.
To get on to the internet you need an internet-ready computer system.
This computer system could be a desktop, a laptop or even a palmtop. For it to be
ready to connect you to the internet it needs to have:
 a telecommunications connection in the form of a modem and dialup
connection or a broadband connection
 a browser
 a link to an internet service provider.
What does a modem do?
It is a device that changes your computer’s signals into a form that can be sent down the
phone system.
What is a dialup connection?
It uses a modem and an ordinary phone line to dial up the number of your ISP that
connects you to the internet. Data is transmitted at a speed of 56 Kilobits per second.
What is a broadband connection?
A broadband connection is a high-speed telecommunications link.
You can get a broadband connection using either a digital subscriber line (DSL) or a
cable modem. BT digital subscriber line (DSL) gives speeds of maximum 512 Kbps
download and 128 Kbps upload.
Cable modems can deliver speeds of up to a maximum of 10 Megabits per second.
Actual speeds are around 1 Mbps per second because the cable bandwidth often has to
be shared with other users.
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What is a browser and what does it do?
A browser is the software that fetches web pages for you and displays them on your
screen. The most common browser in use is Microsoft Explorer.
To get your browser to fetch
pages you can type in the
address of the page in the
address bar.
Or you can click on a
hyperlink.
Your browser will remember
where web pages are, if you
add them to your favourites.
A browser lets you
jump back and
forwards between
pages using the back
and forward icons.
It will even tell you which
pages you have visited
simply by clicking on the
history icon.
O nl in e/ o f fli n e
Once your computer is connected up and ready to send and receive information it is said
to be online. When your computer is not ready to send and receive information it is
offline. Working offline can be quite useful especially if you have a dialup connection that
limits your time online. For example, you can download web pages and look at them
offline, or prepare your e-mail messages offline and then go online to send them.
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Internet service providers (ISPs)
Before you access the internet you need to have an agreement with an internet service
provider (ISP). To access the internet you have to log on to your ISP’s computer that
then helps you access the internet. Your ISP helps your browser find web pages, gives
access to web-based e-mail by storing and forwarding data to your computer, and
provides access to newsgroups and chat rooms.
Some ISPs give you space on their servers to store your own web pages.
You pay a monthly service charge for the ISP’s services and, in many cases, the
telephone charges as well, though this varies according to the ISP.
How do you choose between ISPs?
Look at the following features that vary from ISP to ISP. Each ISP has different deals
and agreements. It is worth looking around, before you take out a contract, for:
 how much they charge
 how reliable the service is. Some are more reliable than others. Some ISPs
experience regular difficulties and either slow down their service or suspend it
because their systems go down, are overloaded or need maintenance
 how long you can stay online. Some have strict time limits
 how efficient the service is. Some have more powerful servers than others and so
their service is altogether faster.
Mobile Internet technology
This technology uses devices that let you access the internet while on the move. There
are different types and examples. All of the devices have:
 mobile-phone technology
 a mini-browser
 internal memory
 a processor
Some are phones with a browser – smartphones.
Some are palmtops with phone technology built in.
They often have features such as:
 touchscreens
 WIMP HCI
 mini-browser
 calendar
 a database
 a calculator
 mobile phone connection to access the internet as well as make phone calls and
send text messages.
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Exercise 6
1.
2.
3.
4.
5.
6.
7.
8.
What is the internet?
What does a computer system need to be ready to access the internet?
What is the job of a modem?
What is a browser and what does it do?
What services does an ISP provide?
What should you look out for when choosing an ISP?
What features would a palmtop with mobile internet capability have?
Use your computer magazines and/or an internet search engine to get the
technical details and illustrations of the most up-to-date mobile internet
technology.
What services are there on the internet?
Apart from e-mail there is the world wide web, newsgroups, chat rooms and search
engines.
The most obvious one is the world wide web (WWW).
The world wide web is made up of web pages that are stored on servers worldwide. Web
pages are multimedia documents that can hold text, graphics, animations, sounds and
videos. They are linked together using hyperlinks.
What is a hyperlink?
A hyperlink is used to link web pages together.
To the user a hyperlink is either a graphic or some underlined text
http://www.bbc.co.uk
The user clicks on the graphic or text with the mouse and the browser fetches the web
page.
The hyperlink holds all the information that the browser needs to find and display the
web page.
How do you create a web page?
Most web pages are created using a web page authoring package. You will probably
use a web page authoring package as part of the General Purpose Packages part of this
course (see reference).
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--------------------------------------------------------------------------------------------------------------Web page
authoring
packages
enable the
user to
use a GUI
to
assemble
the
graphics,
text and
sound that
make up
the web
pages.
You can
also use a
page
description
language
called
HTML
to set up your pages. This is short for Hyper Text Markup Language. HTML uses
tags or commands to describe the various elements that make up a web page such as
headings, colours and graphics.
HTML code looks like this.
<head>
<meta http-equiv=‘Content-Type’ content=‘text/html;
charset=windows-1252’>
<meta name=‘GENERATOR’ content=‘Microsoft FrontPage
4.0’> <meta name=‘ProgId’
content=‘FrontPage.Editor.Document’> <title>Jobs</title>
</head>
<body bgcolor=‘#CCFFCC’>
<p class=‘MsoNormal’><b>Jobs&nbsp;<o:p>
</b>
</o:p>
</p>
<div align=‘center’>
<center>
<table border=‘1’ width=‘100%’>
<tr>
<td>
<p class=‘MsoBodyText’>&nbsp;<o:p>
</o:p>
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Exercise 7
1. Complete this paragraph using the words given below.
The world wide web is made up of ________ pages that are stored on
servers worldwide. Web pages are _________________ documents that
can hold text, _______, ________, animations and videos. They are
linked together using __________.
hyperlinks, multimedia, graphics, sounds, web
2.
3.
4.
5.
What are hyperlinks used for?
Give two examples of what hyperlinks look like.
What is the Hyper Text Markup Language used for?
Write out the line in the HTML code above that sets the background colour for
the page.
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What other services are on the internet apart from
web pages and e-mail?


You can join in discussions
You can join a newsgroup and take part in discussion on a whole range
of topics on subjects such as the world of art, educational issues,
physics, chemistry, biology, literature, films, theatre, social problems,
hobbies and leisure.
You can join a chat room: these are electronic groups that are less
structured than newsgroups and in which people have discussions on a
wide range of topics.
Netiquette is very important when using chat rooms or newsgroups. (See page 12 on
netiquette.)
You can use search engines to look for web pages
Doing a simple search
You can search for web pages by simply typing in a brief description of what you are
looking for and the search engine looks for it, sends the results to your computer and
your browser displays them. In this graphic you can see the result of a simple search for
images of robots.
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A complex search
Sometimes your search can turn up too many results for you to look at. If that happens
you need to carry out a complex search with conditions in it that will help the search
engine focus in on the subject you are interested in and narrow down the results.
The advantage of carrying out a complex search is that it is more specifıc and returns
fewer, more exact, results.
This search is looking for web pages on lochs in Scotland apart from Loch Tay, Loch
Lomond and Loch Ness.
Exercise 8
1. Complete this paragraph using the words given below.
Apart from looking at ____ pages, you can use the ________ for having
discussions with people using ___________ and chat rooms. You can
buy and sell things using sites such as Amazon and ____. You can use
______ engines to find web pages for you.
internet, newsgroups, search, web, eBay
2. Log on to the internet and open up your favourite search engine. Carry
out a simple search. Search for: ‘rivers’. How many pages did your
search find?
3. Using your search engine carry out a complex search. Search for:
‘Scottish salmon rivers NOT Tay NOT Tweed’. How many pages did
you find?
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Software available on the internet
There is a wide range of software that you can download from the internet. They all
have different agreements attached to them. You really should know a bit about each
one so that you do not break any copyright agreements.
Freeware licence agreements let you use the software and even make copies of it
and given them away to people. It is against the terms of the agreement to change
the software or sell it.
Device drivers for printers and CD-writers are examples of freeware as are some
games.
Shareware
Shareware software comes with a free 30-day trial period. After the 30 days you
should register and pay a fee or delete it from your computer. Once you have done
this you can make copies of the software and distribute them to other people. They
then have a free 30 days before registering and paying.
The disadvantage of this system is that it relies on people’s honesty. Many people
do not pay.
Commercial software
Commercial software is bought across the counter in shops such as PC World or
through the internet. You have to pay the full price up front and the licence
agreements are very detailed. You are often limited to making one backup copy or
simply are allowed to copy the software once on to your hard disk and keep the CD
as a backup.
Breaking these licence agreements really does break the law (see Copyright Designs
and Patents Act page 26).
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Exercise 9
1.
2.
3.
4.
Is freeware completely free software that you can do what you like with?
What is the disadvantage of shareware?
How many copies of commercial software are you normally allowed to make?
Which law is used to protect commercial software?
Videoconferencing
Videoconferencing is using a computer
network to send audio and visual data
to enable people in distant locations to
have face to face meetings.
The simplest form of a videoconference
is a point-to-point conference.
This connects two people at
two different locations using simple webcams, microphones and speakers attached
to their computers.
Sounds and images are captured by the
microphone and camera. They are then
transmitted across the network, which
can either be a LAN, a WAN or even the
internet.
A more complex form of
videoconferencing is known as multipoint
conferencing. This sets up audio-visual
links across a network linking several
people in distant locations.
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What are the advantages of videoconferencing?
People who are located in different countries and even continents can have face to
face meetings where they can discuss documents displayed in the conference and
make decisions.
This avoids the need for travelling large distances and staying in hotels, and it can be
set up quickly, saving time and money.
Teams of workers can be brought together quickly no matter where in the world they
are located.
Networks and social issues
Information on the internet
The internet is a rich source of information. You can find out what you want on any
subject by searching on the internet. From education to travel, from gardening to
space flight – there are thousands of web pages on every subject you can think of and
plenty of search engines to help you find what you are looking for.
Advantages of access to this information
Having access to this information can help you find work, be successful at school and
college, and also be a great help in business and leisure.
Including everyone
The social issues arise because not everyone has access to this wealth of information.
This means that some people are at a disadvantage in many areas, whether it is work,
buying and selling, education or leisure.
There are signs that this problem is gradually being solved as more and more ways of
accessing the internet are developed. We can now access this information on the
internet from an internet-ready laptop or PC, from internet-ready phones or
smartphones, from public libraries that have PCs online to the internet, and from
internet cafés.
Networks and isolation?
There is a worry that some people prefer to communicate using computers rather than
meeting people face to face. The fear is that people will isolate themselves from
others and spend most of their time on the computer system e-mailing and messaging,
playing games, shopping or wandering round the world wide web.
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There’s nothing wrong with using e-mail or messaging, checking out websites or
searching for information or even gaming on the internet. However, like everything
else, if you indulge in it too much then it can be a bad thing and, taken too far, it could
lead to people becoming detached from the world around them.
Perhaps the best thing is to keep a balance between spending time on our networks
and keeping in touch with people face to face.
This is a subject work thinking about and discussing with your teacher and your
friends.
Exercise 10
1. What are the advantages of having access to the information held on the
internet?
2. Why is it important to think about making sure that everyone has access to this
information?
3. Think about the question of networks and isolation.
(a) How much time on the internet is too much?
(b) How much time should you limit yourself to per week on the net?
(c) List the activities you would miss out on if you spent all your spare time on
the net.
Legal issues
Using networks to break copyright laws
People unfortunately use networks to commit crime. Networks can be used to:
 hack into business networks and
steal or corrupt data
 hack into business networks and
cause damage by leaving viruses
 commit financial fraud such as
stealing money from bank accounts
 break copyright law by illegally
transferring software, data or other
files.
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Privacy
Some people disregard others’ right to privacy and use networks to send unwanted
e-mails, chain-mail, adverts, junk e-mail or spam.
The laws shown below are designed to prevent all this. For details see the General
Purpose Packages support notes.
Computer
Misuse Act
1990
Data
Protection
Act 1998
Copyright,
Designs and
Patents Act
1988
Exercise 11
Complete this table showing which laws some people break using networks.
Crime
Law broken
Hacking into business networks to
steal or corrupt data.
Hacking into business networks to
cause damage by leaving viruses.
Using networks to steal personal
details.
Illegally transferring software, data or
other files using networks.
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Ethical Issues
Why do we need to look at the ethical issues relevant to
computer networks?
When we are looking at ethical issues we are basically looking at right ways and
wrong ways to use networks.
Networks are very powerful communication tools and, used properly, they can bring
great benefits to people and society in general. We can use them to communicate,
and to share and swap data with people simultaneously around the world. We can
use them to learn, to have open access to information, to drive our businesses and
careers as well as help us in our leisure pursuits.
Used irresponsibly, and for the wrong purposes, they can spread bad feelings and
disinformation, stir up hatred, be a source of crime and corruption and generally
undermine the bonds that hold society together.
Codes of conduct when using networks
Because people misuse networks and indulge in anti-social behaviour, businesses
and organisations have set out codes of conduct for
network users. These are usually called ‘Acceptable Use
Policies’ and they are generally based on the need to:


respect other people and their rights and property
adhere to the law.
On the internet there are many examples of netiquette
codes of conduct that also set out clear codes of conduct
to guide how people should behave when using networks
to communicate.
Above all, as individuals using computer networks we need to be aware of ethical
issues and use our networks responsibly and for positive purposes such as
education, communication and business and, at all times, respect other people and
their rights when using these very powerful communication tools.
Exercise 12
1. What makes networks such a powerful communication tool?
2. Describe the possible results if networks are misused.
3. What is the basis of many codes of conduct that are designed to guide people’s
behaviour when using networks?
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Network and Communications Questions
1.
2.
3.
4.
What is a LAN?
List two advantages of using a LAN.
What is the most common type of cabling used in a LAN?
An office manager wants everyone in the office to read a document, add
some comments and send it back to her. Describe how this could be
done using the LAN.
5. You are working with a group of pupils to produce a poster for the school sports day.
There is only one good colour laser printer in the school. How could you use the
school LAN to help you?
6. Fill in this table with information on the internet connections you have either at
school, at home or both.
Type of connection
Speed of connection
School internet connection
Home internet connection
7. Use the word below to complete this table.
This type of network can connect computers
across only a small area such as a school, an
office building or a factory.
This type of network can connect computers
across countries right round the world.
This means encoding data.
You use these to stop unauthorised people
from gaining access to your network.
This manages the print queue on a network.
Your computer needs one of these to connect
it to a LAN.
This is a powerful computer that is shared by
many users.
Encryption, multi-access system, LAN, network interface card, passwords, WAN,
printer server
8. What is netiquette?
9. Why is a set of netiquette rules needed?
10. Write down a sample of two netiquette rules.
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Communications and Networks
--------------------------------------------------------------------------------------------------------------11. Use the words below to complete the table.
This will find web pages for you.
If you join one of these, the discussion
will be focused on a specific topic.
You can use this to type in and send
instant messages to anyone in your
group.
You can use a LAN, WAN, or the
internet to send letters to people.
This is an efficient way to send files to
people across a network.
e-mail, newsgroup, search engine, text messaging, e-mail attachments
12. What is a complex search?
13. What is the advantage of using a complex search?
14. Look at these three searches carefully.
a) Find a list of web pages on lochs.
b) Find a list of web pages on all the lochs in Scotland except Loch Lomond
or Loch Ness.
c) Find a list of web pages on all the freshwater lochs in Scotland except Loch
Lomond or Loch Ness.
(i) Which of these is a complex search?
(ii) Which of these will produce the smaller number of results?
15.
16.
17.
18.
19.
20.
21.
Why do you need a browser to access the internet?
What is a web page?
What is a hyperlink used for?
What language can be used to describe a web page?
Describe a dialup connection.
What is a broadband connection?
Complete this table.
An internet-ready computer must have:
(a)
(b)
(c)
22. List two advantages and two disadvantages of using e-mail.
23. What does the Bank of Scotland use to connect its branches across Scotland,
a LAN or a WAN?
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Communications and Networks
--------------------------------------------------------------------------------------------------------------24. If you are sending your computer’s digital information down a phone line,
which one of these do you need?
(a) Browser
(b) Search engine
(c) Modem
(d) Hyperlink
25. Complete this table using the words below.
(a) This means your computer is not
connected to a network and
ready to send and receive data.
(b) This is a language for defining
web pages.
HTML, Offline
26. If your computer is connected to a network and is ready to send and receive data
it is:
(a) offline
(b) attached
(c) hyper-linked
(d) online.
27. If you type in the address of a web page correctly this software will fetch it for you
and display it on the screen.
28. If you wanted to discuss the latest type of laptop computer, which internet service
would you use?
29. If you do not know the address of a web page how could you find it?
30. ‘There is only one reason for using e-mail: it is faster than “snailmail”.’
Is this statement true or false?
31. Which of these does a computer need in order to be internet ready?
(a) Modem
(b) Browser
(c) HTML
(d) Dialup or broadband connection.
32. List three ways networks are commonly used to break the law.
33. Which law are you breaking if you ignore the licence agreement that comes with
commercial software?
34. Why is it necessary to have tight security surrounding personal data held on a
computer network?
35. Read the section on the ethical implications of networks and then complete this
table.
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Communications and Networks
--------------------------------------------------------------------------------------------------------------Examples of benefits that networks
bring when used positively and
responsibly
Examples of the damage that
irresponsible use of networks can bring
36. If someone had no access to the internet how would they be disadvantaged
when:
(a) looking for a job?
(b) getting information for a school project?
(c) buying a new computer?
37. How could you access your web-based e-mail while travelling as a passenger
a bus?
38. An international business has a WAN with broadband communications links.
How could this be used to set up face to face meetings with people in different
countries?
39. Why do many desktops now come with a network interface card already
installed?
40. Apart from a printer server, name two other servers that might be on a client
server LAN.
41. Could a laptop be used as a network client? Explain your answer.
42. What does an internet service provider do for its customers?
43. ‘You don’t pay a penny for shareware’. Is this correct? Explain your answer.
44. What is the difference between freeware and shareware?
45. Explain how videoconferencing works.
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Networks: Answers to Questions
1. A LAN is a local area network. That is a network that is located in one area or
building, for example a school, a factory or an office. You might even have a LAN at
home.
2. Any two of: sharing peripherals, sharing data files, communicating using e-mail.
3. A twisted pair of copper cables.
4. She would prepare the document then use the LAN to send everyone a copy,
probably using internal e-mail. People would then make their comments and
changes then return their copy to her using the network. She could also place the
document in a shared area and let everyone make a copy of it before making
changes and returning it to the shared area.
5. Everyone working on the poster could use the LAN to share the colour laser printer.
6. Simply get the details of your school’s network telecommunications link and your
home set up, for example 56K modem, broadband connection, ISDN line, cable
modem.
7.
This type of network can connect computers
LAN
across only a small area such as a school, an
office building or a factory.
This type of network can connect computers
across countries right round the world.
WAN
This means encoding data.
Encryption
You use these to stop unauthorised people
from gaining access to your networks.
Passwords
This manages the printer queue on a network.
Printer server.
Your computer needs one of these to connect
it to a LAN.
Network interface card.
This is a powerful computer that is shared by
many users.
Multi-access system.
8. Netiquette is a code of rules that guide behaviour when using networks.
9. Without such codes/guidelines people would use networks for all sorts of activities
that could cause offence and even break the law.
10. Some examples are:
 ‘Do not cause flame wars.’
 ‘Be patient with other people.’
 ‘Do not send any offensive e-mail.’
 ‘Do not send chain letters.’
 ‘Use the network positively.’
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Communications and Networks
--------------------------------------------------------------------------------------------------------------11.
This will find web pages for you.
Search engine
If you join one of these, the
discussion will be focused on a
specific topic.
Newsgroup
You can use this to type in and send
instant messages to anyone in your
group.
Text messaging
You can use a LAN, WAN or the
internet to send letters to people.
E-mail
This is an efficient way to send files
to people across a network.
E-mail attachments
12. A search with two or more parts or conditions in it.
13. A complex search will be more specific and return fewer, more exact, results.
14. (i) (b) and (c) are complex searches
(ii) (c) will return the smaller number of results.
15. A browser fetches web pages for you and displays them on your screen.
16. A web page is a multimedia document that can hold text, graphics,
animations, sounds and videos.
17. A hyperlink is used to link web pages together.
18. HTML
19. It uses a modem and an ordinary phone line to transmit data at a speed of 56
Kilobits per second.
20. You can get a broadband connection using either a digital subscriber line
(DSL) or a cable modem. BT digital subscriber line (DSL) gives speeds
of maximum 512 Kbps download and 128 Kbps upload.
21. An internet-ready computer must have a:
(a) telecommunication connection in the form of a modem and dialup
connection or a broadband connection
(b) browser
(c) link to an ISP.
22. (a) Advantages: It costs less than surface mail; it is quicker; using internet-based
e-mail you can check your mail from anywhere in the world; you can send
copies to many people at the same time.
(b) Disadvantages: On many systems you have to check your e-mail to know that
somebody has contacted you; viruses can be hidden in e-mail attachments; lots
of spam arrives by e-mail.
23. A WAN.
24. Modem.
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25.
(a) This means your computer is not connected to a
network and ready to send and receive data.
Offline
(b) This is a language for defining web pages.
HTML
26. Online
27. Browser
28. Chat room or a newsgroup
29. Use a search engine.
30. False. There are other reasons for using e-mail apart from speed: there is cost,
access to e-mail from anywhere in the world and the ability to send multiple copies
simultaneously.
31. (a), (b), (d)
32. Any three of:

hack into business networks and steal or corrupt data

hack into business networks and cause damage by leaving viruses

commit financial fraud

steal money from bank accounts

break copyright law by illegally transferring software, data or other files.
33. Copyright Designs and Patents Act.
34. It is a requirement of the Data Protection Act.
35.
Examples of benefits that networks
Examples of the damage that
bring when used positively and
irresponsible use of networks can bring
responsibly
They enable people across the world to
communicate.
They give people access to information
that can help their education and careers.
They can be used to send offensive and
intrusive e-mails.
They can be used to spread disinformation
and propaganda.
They can be a means of buying and
selling, and so help the economies of the
world.
In local networks they enable us to share
peripherals.
They can be used for stealing and fraud.
They enable us to send and share data
files.
© Learning and Teaching Scotland
They can be used to hack into systems
and use other people’s computer-based
equipment.
They can be used to hack into networks
and copy, change or delete data.
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36. (a) Other people could access web pages with job adverts, could apply
for jobs online and could even send their CVs online.
(b) They could not access the information held on web pages.
(c) They would not have access to the online stores that often give very good
deals on computer hardware.
37. You could use some form of mobile internet technology such as a smartphone.
38. It could be used to set up a videoconferencing system.
39. Because most PCs nowadays are connected to networks either at home or at
work.
40. File server, web server, applications server.
41. Yes. A desktop or a laptop could act as a client as long as it had the correct NIC.
42. An ISP gives you access to the internet and its web pages, chat rooms and
newsgroups. It also gives you e-mail and gives you storage space on its servers
to let you mount your own web pages.
43. No, you have 30 days free trial and then you have to register and pay for the
software or delete it from your computer.
44. Freeware costs nothing at all and you can do anything you like apart from sell it
or alter it. Shareware has to be paid for eventually and you are only allowed to
to copy and distribute it after you have registered and paid.
45. Videoconferencing uses computer networks to provide an audio-visual link
between people. Sounds and images are transmitted across the network using
microphones and digital video cameras or webcams.
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Answers to Exercises
Exercise 1
1.
2.
3.
4.
There are many examples. A sample four are: an insurance office, a bank, a
school, a hospital.
She could post the master copy of the document in a shared area and let
everyone take a copy that they could then edit.
You could use the LAN to send out an e-mail to people asking them to
volunteer to help put the newsletter together.
Sharing data, sharing peripherals, a means of communication.
Exercise 2
1.
2.
3.
4.
5.
Twisted pair of copper wires; fibre-optic cable.
Because it is easy to install and there is no need for lots of cabling.
A NIC is needed so that the computers can communicate with other devices on
the network.
A server is a powerful computer system that manages resources that are
available to clients on a network.
A client is a workstation on a network.
Exercise 3
Complete this table comparing a LAN and a WAN.
LAN
WAN
Distance covered Limited area such as a
building or a factory.
No limit to the area:
across countries,
continents, the world.
Means of linking Copper or fibre-optic
computers
cables. Wireless links.
Telecommunications
links.
Exercise 4
1.
2.
3.
4.
5.
Locks on computer rooms, locks on terminals, terminals with no floppy drives or
CD-drives.
When the users log on, the computer system checks their ID and
password and tries to match them with those kept on file. If there is a
match they are allowed on to the system.
Biometric systems that hold data about fingerprints and eye scans.
Encryption means that any data that is hacked into on a network will be
meaningless to the hacker because it is encoded.
In case it gets lost or damaged.
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--------------------------------------------------------------------------------------------------------------6.
A network is a series of computer systems that are linked together so that
they can communicate and share data. A multi-access computer is a very
powerful single computer system with lots of terminals attached to it
enabling many people to use it at the same time.
7. They are large businesses and organisations such as banks and universities.
Exercise 5
1.
2.
3.
4.
It is cheap. It is quick. You can access internet-based e-mail from anywhere in the
world. You can send mail to many people at the same time.
Some people use e-mail’s ability to send mail to many addresses
simultaneously to advertise products and services. We have all received
unwanted e-mail messages. They can be very annoying and intrusive. They are
known as spam.
You can only send and receive messages to and from people in your
messaging group. Messages appear instantly when you are online, you
do not have to open a mail in-box then open e-mail messages.
(You can add other code items and reasons to this list).
Netiquette code item
Reason
Do not start flame wars.
Using e-mail to start an argument can
quickly get out of control and offend a lot of
people as well as jam up the network with
meaningless traffic.
You would not use bad language or be
impolite when talking to people face to
face; so why should you do so just
because you are using e-mail.
Spamming can cause offence and, if you
want to sell something, can upset people
and lose you customers.
Do not use bad language,
always be polite.
Do not post unwanted
mail or use e-mail to spam.
Be patient with people who use
e-mail to ask awkward questions.
5.
6.
7.
Not everyone uses e-mail sensibly. Some
people try to be silly or awkward just
because they are using e-mail. The best
policy is to avoid getting angry or upset and
give a calm reply.
Show your printed copy of a netiquette code to your teacher.
They are a convenient way of sending data files across networks, including
the internet.
(a) Some e-mail providers have limits to the size of files that you can send as
an attachment. You need to check this out if you are thinking of sending a
large file.
(b) Some people use e-mail attachments to send viruses around networks.
You need to have anti-virus software to protect you from the problems
this can cause. It is best to delete unwanted and unexpected e-mail
attachments without opening them.
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Exercise 6
1. The internet is a worldwide network that links computers and networks right across
the globe.
2. It needs a modem, a browser, a telecommunications link and a link with an ISP.
3. It changes the digital information held in your computer into a form that
can be sent down the telecommunications link.
4. A browser is the software that you use to search the internet for web pages. It
fetches web pages for you and displays them on your screen.
5. Web-based e-mail, access to chat rooms and newsgroups, space to
upload your own web pages, access to the world wide web.
6. The cost, the reliability and speed of their services, as well as the time
limits to your internet connections.
7. A top of the range mobile palmtop will have: touchscreen, WIMP HCI, mini-browser,
calendar, database, calculator, mobile phone connection to access the internet, text
messaging, ability to take and send photos, limited photo editing capabilities, usual
phone services.
8. Show the results of your internet search for ‘up-to-date mobile internet
technology’ to your teacher.
Exercise 7
1. Complete this paragraph using the words given below.
The world wide web is made up of web pages that are stored on servers
worldwide. Web pages are multimedia documents that can hold text,
graphics, sounds, animations and videos. They are linked together
using hyperlinks.
2.
3.
4.
5.
Linking web pages together.
They are usually underlined text or a graphic.
Constructing web pages.
<body bgcolor=’#CCFFCC’>
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Exercise 8
1. Complete this paragraph using the words given below.
Apart from looking at web pages you can use the internet for having discussions
with people using newsgroups and chat rooms. You can buy and sell things
using sites such as Amazon and eBay. You can use search engines to find
web pages for you.
2. Show the results of your search to your teacher.
3. Show the results of your complex search to your teacher.
Exercise 9
1. Freeware is free. You do not have to pay for it. However, you cannot do what you
like with it. The copyright still belongs to the author and you cannot sell it or make
changes to it.
2. It relies on people’s honesty. If people do not register and pay then the author
gets nothing for writing the software.
3. Usually only one copy as a backup.
4. The Copyright Designs and Patents Act.
Exercise 10
1. It will help you in your education, in finding jobs, in leisure pursuits, even in buying
and selling goods.
2. If people are excluded from access to this wealth of information they can be at a
disadvantage when it comes to education, jobs and the web-based bargains
available when it comes to buying and selling.
3. You should come up with your own answers to these questions, perhaps after
discussion with your teacher.
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Exercise 11
Complete this table showing which laws some people break using networks.
Crime
Law broken
Hacking into business networks to
steal or corrupt data.
Computer Misuse Act
Hacking into business networks to
cause damage by leaving viruses.
Computer Misuse Act
Using networks to steal personal
details.
Data Protection Act
Illegally transferring software, data or
other files using networks.
Copyright Designs and Patents Act
Exercise 12
1. The fact that you can communicate with many people right round the world.
2. Misusing networks can spread bad feelings and disinformation, stir up hatreds,
be a source of crime and corruption and generally undermine the bonds that
hold society together.
3. Respect for other people’s rights and their property.
© Learning and Teaching Scotland
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