4.
The two most common methods of connecting to the Internet are using a modem and telephone line or a broadband connection. Other methods
such as ISDN are also available.
| Information about Modem |
Information about Broadband |
| Connects using a modem and telephone line at speeds up to 56.6KBps. Can be used anywhere there is a 'phone line. Must dial-up before use. Cost around 2p/min or £12/month. Suits infrequent users. |
A high speed connection usually made using either ADSL and a telephone line or a cable TV connection and a cable modem. Speed ranges
from 560KBps to 2048KBps. Always connected to Internet. Only available to about 85% of UK. Fixed cost of £15+ per month. Suits frequent users.
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| Advantages of Modem |
Advantages of Broadband |
| Can connect anywhere there is a telphone line. |
The fastest transmission speed (ten times quicker than a modem). |
| Pay for how much you use it, so cheapest if not used very much. |
Pay a fixed monthly fee, then can use it as much as you want. |
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| 5.
| The most important services that are provided on the Internet are listed below :
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| Service |
Details |
| Electronic Mail |
Using electronic mail (email) you can send messages and computer files to
any Internet user around the world.
- Each user has a unique address such as john@heathtrading.co.uk
- Files such as word processed documents can be sent with an email as an attachment.
- Messages are stored in a mailbox. They can be put into folders such as Inbox and Outbox.
- You can automatically reply to an email you have received or forward an email you have received to another person.
- An address book stores the email addresses of people you email regularly so you don't have to remember them.
- An email can be sent to many people simultaneously. A stored list of people to send an email to is known as a mailing list.
- A digital signature can be added to an email so the recipient can verify the identity of the sender.
- Advantages : Email can arrive more quickly than post and information can be sent more cheaply by email than by most other methods. You can read your email from any computer.
- Disadvantages : Less people have access to email than to post, packages can't be sent by email, viruses can spread through
email and SPAM email can be a nuisance.
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| World Wide Web |
The Word Wide Web (WWW or web) is a vast collection of information on many subjects
which anyone can read and add information to.
- The web is made up of many sites, each identified by an address (or URL). A site is made up of pages.
- Information on a site can include text, images, sound and video.
- A hyperlink is text or a picture that when clicked on takes you to another web page.
- To access web pages you need to use a web browser package.
- A web browser lets you view web pages, navigate (move) between pages, keep a list of your favourite sites,
remember sites you have visited recently (your history), and provide feedback to a site through forms.
- Copies of recently visted web pages may be stored on your hard disk drive so that they can be redisplayed quickly. This is known as caching.
- A search engine is a web site that you can use to seach other web pages for information on a particular topic.
- Your home page is the page that is displayed when you load your web browser.
- A web portal is a page that acts as a starting point to obtain information from the world wide web.
- Web sites are defined is a language called Hypertext Markup Language (HTML).
- The web can be used for many purposes such as research, advertising, distributing software, customer support and e-commerce.
- Advantages : Large amount of information, information can be up-to-date, multimedia information.
- Disadvantages : Information may be unreliable as quality of source not known, can be too much information, not everyone can use the web.
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| USENET Newsgroups |
Newsgroups provide a discussion forum on which people can ask questions which other users can respond to and on which notices of general interest can be posted.
- A program called a news reader is required to access USENET.
- There are many newsgroups, each of which is dedicated to a particular topic.
- Advantages : One message will be read by many people who are interested in a topic, good way to communicate with people who know about a topic.
- Disadvantages : Some newsgroups overtaken by SPAM messages, difficult to know true source of a message.
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| Internet Relay Chat |
Internet Relay Chat (IRC) let users "chat" to each other over the Internet.
- A chat is in the form of text rather than speech.
- Chatting is interactive as users have the oppportunity to immediately respond to messages from other users.
- Advantages : An interactive system.
- Disadvantages : Must be logged on at same time as other users to chat, people can disguise their true identities.
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| File Transfer Protocol |
File Transfer Protocol (FTP) is used to retrieve files over the Internet.
- Some FTP servers require you to enter a username and password others let you access files anonymously.
- FTP is also used to upload files to the Internet such as a web site you have created.
- Alternatively files can be downloaded using the World Wide Web.
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| Broadcasting |
Radio and low quality television pictures can be broadcast over fast broadband Internet connections.
- You need a broadband connection to access these services. A modem and telephone line is too slow.
- Advantages : Can watch/hear any program anywhere, big range of programs, easy and cheap to set up as a broadcaster.
- Disadvantages : Quality of pictures not very good, skills and hardware required to received broadcasts.
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| 6.
Nobody controls the information that is on the Internet so unsuitable material such as pornography and racist abuse can be found. Filtering can be used to try and prevent access to this material.
- Advantages : Can prevent access to unsuitable material.
- Disadvantages : Can sometimes let unsuitable material through, may block useful sites.
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| 7.
| A private network within a company that provides facilities such as web sites and email is known
as an Intranet.
An Intranet can be connected to the Internet through a firewall.
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| 8.
| Here are some advantages of the Internet :
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