Study Unit 4 computer systems and data communication
Wireless Network Configurations
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- Navigate this page:
- The Internet What is the Internet
- What is needed to connect to the Internet
- Internet Service Providers
- Modem
- Telecommunication link
- Integrated Services Digital Network (ISDN)
- Internet Services
- How to Access the World Wide Web
- Study Unit 5 THE ROLE OF INFORMATION AND COMMUNICATION TECHNOLOGIES IN BUSINESS
Wireless Network ConfigurationsWireless networks can be configured in an ad hoc/peer-to-peer arrangement or as a local area network. Ad Hoc/Peer-to-Peer Configuration This is the most basic wireless network configuration. It relies on the wireless network adapters installed in the computers that are communicating with each other. A computer within range of the transmitting computer can connect to it. However, if a number of computers are networked in this way, they must remain within range of each other. Even though this configuration has no real administration overhead, it should only be a consideration for very small installations. The InternetWhat is the Internet?The Internet which is also known as the Net is simply a network of networks. It is a world wide computer network that interconnects computer networks across countries. A network is a group of computers that are connected so that they can share information. The computers are linked together through high speed telephone wires, satellite and any other telecommunication system such as cable networks. All computers on the Internet communicate with one another using the Transmission Control Protocol/Internet Protocol suite, which is commonly abbreviated to TCP/IP. As a network of networks, the Internet allows people on one network to share information with people on another network that may be thousands of miles away. Through the Internet, one has access to a wide variety of services which include : vast information resources, interactive collaboration tools, multimedia displays, real-time broadcasting, shopping opportunities, and much more. These services are available through the: World Wide Web, electronic mail (email), file-transfer between any two computers and, remote access to a computer connected to the Internet. What is needed to connect to the InternetThe minimum set of requirements to connect to the Internet is: a computer attached to an Internet entry point (a service provider) via a telecommunication link such as the telephone line and a modem. These are discussed in detail below. Internet Service ProvidersAn Internet Service Provider (ISP) is a company that gives you access to the Internet. In Zimbabwe the common ISPs are ComOne, ZARNet, AfricaOnline, Ecoweb, ZOL , PowerTEL and many others. You sign up for an Internet access account through your selected ISP. Once you sign up for a dial-up account with an ISP, you will be able to communicate through the Internet and use the services offered, such as email and Internet access. Your ISPs can also provide you with numerous other Internet related services, such as domain name registration and website hosting. ModemWhen you are connecting through a telephone link, a modem is required. The modem must be connected to a telephone line to dial up your ISP’s computer network. A modem (MODulator - DEModulator) is a device that translates digital (numerical) signals from your computer into analogue signal (sounds) that are acceptable for an ordinary telephone line. A modem could be internal, that is, attached on the computer’s motherboard or connected external through a communication port on your computer. To connect to the Internet using a dial-up connection you need a modem with a speed of 56 Kbps modems, which is the maximum for an ordinary telephone line. The speed at which data circulates through the modem and the telephone line is called bandwidth. The first modems had very low bandwidth of 300 to 1200 bit per second (bps). Today, even 14.4 Kbps (kilobit per second) and 28.8 Kbps modems have become obsolete. 
Telecommunication linkA telecommunication link such as the telephone, satellite, fibre optics is required for connecting to the Internet. For a dial-up connection, a telephone link is required. When you dial to link your computer to the ISP network, your computer is connected to the Internet. As with ISP, your telephone services provider will offer many different plans and charging systems from flat rates to blocks of time. You must find the plan that works best for you according to prices that are offered and your specific needs. It is always better to connect to the Internet on a direct telephone line through an automatic connection system because the quality of the line is very important. However, some technical solutions can correct mistakes and remove noise and disturbances. When the Internet entry point is in your local area, you will not need to pay for an intercity or trunk call, but for a local call. In Zimbabwe we dial 041 as the local call to connect to the Internet. This Internet connection will provide you with access to the entire world through your local connection. Please note that you are responsible for paying the telephone bill for the time you will be connected to the Internet. Other types of telephone connection are dedicated lines, and the Integrated Services Digital Network (ISDN) Dedicated linesA dedicated line is a telecommunication path between two points that is available 24 hours a day for use by a designated user. A dedicated line is rented from a telephone company, in which case it is called a leased line. Thus unlike dial-up lines, it is not shared in common among multiple users. In this type of connection, you will pay the agreed rate to ISP, but you do not pay additional costs for the time spent while surfing the Internet. Such lines are ideal for schools and colleges where the Internet is need throughout the day. Integrated Services Digital Network (ISDN)Using an Integrated Services Digital Network (ISDN) adapter, instead of a conventional modem allows the transmission of data on an ordinary telephone wire at a much higher speed. When you connect using an ISDN adapter in place of a modem, you can access highly graphic webpages with easy and at a fast speed of up to 128 Kbps. This new technology is not readly available in many developing countries. Since ISDN requires adapters at both ends of the transmission, your access provider also needs an ISDN adapter. So before you make the decision to install an ISDN adaptor you must check if your ISP has one. In some countries, ISDN is available from phone companies in urban areas. The web browserIn addition to the things listed above, there are a number of pieces of software that works together to connect us to the Internet. One such software is the Internet browser. The browser helps us to locate websites and allows us to maneuver around or surf the World Wide Web as we view web pages. The two most frequently used graphic browsers are Microsoft's Internet Explorer, and America Online (AOL)'s Netscape Navigator. Before these graphic browsers were in use, Mosaic and Lynx were the most popular browser and these are still available for text browsing. Internet ServicesOn the Internet we have access to a wide variety of services. In this section were are going to discuss, a few of these services, namely, the World Wide Web (WWW), electronic mail (e-mail), file transfer protocol (FTP) and UseNet news. Electronic Mail Electronic mail (e-mail) refers to the sending of digitally encoded messages through the network. Electronic mail is one of the fastest and easiest ways of sending electronic messages from one person to another or to a group. Email systems enable us to conveniently and quickly send a message to many people at one time. Messages sent through e-mail can arrive within a matter of seconds. Although email is used primarily for sending written messages, we can also send and receive pictures, sounds and video images as attachments to the text message. These files are referred to as MIME attachments. MIME stands for Multimedia Internet Mail Extension. This technique was developed to help e-mail software handle a variety of file types. For example, a document created in Microsoft Word can be attached to an e-mail message and retrieved by the recipient with the appropriate e-mail program. They are basically two types of e-mail accounts, these are, the one we can be given by our Internet Service Provider (ISP) and the one we can get free from the Internet. The email account we can obtain from the ISP is some times called the computer-based account. Computer based accounts have the advantage that students can downloads all their messages to read and respond to them offline. That is when they are not connected to the Internet. Students can only connect to download or post their messages. This saves on the telephone bill if the connection is a dial-up connection. The Internet based email account is sometimes known as web-based account. Web based email accounts are usually free of charge and they are available from a number of providers on the Internet. These include yahoo mail, Hotmail, Gmail and many others. The major advantage of web-based mail is that students can easily gain access from any computer with Internet access. The World Wide Web The World Wide Word (WWW) or simply the Web is another commonly used Internet service. The World Wide Web is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. It provides Internet users with a uniform and convenient means of accessing a wide variety of resources including pictures, text, sound and video, available on the Internet. It provides a vast array of experiences including multimedia presentations, real-time collaboration, interactive pages, radio and television broadcasts. Both the teacher and the learner can retrieve documents, view images, animations and videos, listen to sound files, speak and hear voices through the Web. The information is found on files called web pages or web sites. A web site is a set of interlinked files on a web server computer. Each website has an address, known as a “URL,” that locates it on the internet. Websites are typically organized around a “home page” that serves as the entry point to other pages. Websites can present information in words, pictures and sounds, and they can enable us to exchange information with our students. A web page is written in a special programming language called hypertext mark up language (HTML) and its filename ends with file extension html. Hypertext is basically a document containing words that connect to other documents. The principle of hypertext is that one text or web page can refer to or point to another web page, either on the same website or another website somewhere else in the world. Thus it is easy for the web pages to link to another web page on the same computer or different computers, anywhere on the Internet. The pages are linked by special links called a hyperlinks. The hyperlink can be taken as a method of instant cross-referencing of information on web. A hyperlink is shown by a coloured and underlined stretch of text or graphic image where the shape of the cursor changes to a pointing hand. These words are called links and are selectable by the user. In some cases hyperlinks take the form of buttons, images, or portions of images that are clickable. A single hypertext document can contain links to many documents. When you select one of these words or phrases, you will be transferred to the site or page that is linked by the word or phrase. How to Access the World Wide WebFor you to access the World Wide Web a Web browser is required. A browser is a software program that allows users to access and navigate the World Wide Web. There are two types of browsers, namely graphical and text browsers. These are explained in detail below. Text Browsers Text browsers, such as Lynx provide access to the Web in text-only mode. Navigation is accomplished by highlighting emphasized words on the screen with the up and down arrow keys, and then pressing the forward arrow or the Enter key to follow the link. Today, these browsers are fast loosing their popularity due to the development of more user friendly graphical browsers. Graphical Browsers A graphical browser such as Internet explorer, Netscape Navigator, Mozilla and opera, enable us to retrieve text, images, audio and video. These browsers are available for Windows, Apple, Linux and other operating systems. Navigation is accomplished by pointing and clicking with a mouse on highlighted words and graphics. Browser buttons
A Note on Clicking
When using a mouse, the arrow becomes a hand when it is placed over a link. TelnetTelnet is one of the services available on the Internet. Telnet allows the user to log onto computers on the Internet and use online databases, library catalogs, chat services, and more. The major disadvantage of Telnet is that there are no graphics in Telnet sessions. The most common Internet based resources available through Telnet are library catalogs, although most catalogs are now migrating to the Web. As the Web gains more popularity, Telnet is less frequently used as a means of access to information on the Internet, thus why most library catalogues are now migrating to the web. A Telnet program must be installed on your local computer and configured to your Web browser in order to work. To Telnet to a computer, you must know its address. The addresses may consist of words (msu.ac.zw) or numbers (10.10.1.8). File Transfer Protocol (FTP) FTP stands for File Transfer Protocol. This is both a program and a method used to transfer files between computers. FTP is used primarily as a tool to efficiently uploading and downloading files on the Internet. FTP sites contain books, articles, software, games, images, sounds, multimedia and many other forms of information. FTP transfers can also be performed on the World Wide Web without the need for special software. Programs such as WS_FTP for Windows can be used to conduct a file transfer. FTP files can also be retrieved via search engines such as FtpFind, with URL http://www.ftpfind.com. This option is easiest because one does not need to know FTP program commands. The Web browser is sufficient to carry out the process. In fact every time we download software from a Web site to our computer, we will be using FTP.
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