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Lesson 3 Hardware and software to access the Net
Objective Hardware and software needed to access the Internet.

Hardware + Software = Infrastructure

Multiple hardware and software components work together to form the infrastructure needed to access the Internet.

Hardware

Here are examples of the required client hardware you will need:
  1. Desktop machine:A desktop computer or a device dedicated to Internet access.
  2. Internet-enabled devices:Portable Internet-ready devices and appliances.
  3. Network Interface Card (NIC):Also known as a network adapter, NICs are required to connect computers to the network cabling system (using either coaxial cables or RJ-45 connectors). NICs plug into client and server machines and control the exchange of information between the two (known as handshaking).
  4. Modem:An acronym for modulator-demodulator. A modem converts digital signals to analog (outgoing traffic) and analog signals to digital (incoming traffic). Modems are used when dial-up services are needed (called POTS lines), that is, when connecting to the Internet through phone lines. Such connections use RJ-11 connectors, the same plastic square-tipped plug used on household phones.
  5. Cable:The physical wiring used to connect modems to a telecommunications infrastructure, or to connect networks to the Internet.
You can see examples of these hardware requirements in the following MouseOver:
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DSL Connections

Digital Subscriber Line (DSL) is a family of all-digital, high-speed lines that use your normal phone wires with special modems on either end. Most DSL lines are actually ADSL (Asymmetric Digital Subscriber Line). ADSL is optimized for the way many people use the Internet: more downloads than uploads. The line is asymmetric, because it has more capacity for data received by your computer (such as graphics, video, audio, and software upgrades) than for data that you send (such as e-mail and browser commands). Configurations and prices vary depending on your phone company. The downstream bandwidth (data transfer speed from the Internet to your computer) can range from 384 Kbps to 8 megabits per second . The upstream bandwidth (speed from your computer to the Internet) can range from 90 Kbps to 768 Kbps. In real life, however, speeds are usually much lower and depend on the distance between you and the phone company's Central Office or wherever the DSL modem at their end is located. With a DSL line, you can connect your computer to the Internet and talk on the phone at the same time on the same phone line. This feature means that if you currently have two phone lines, one for voice and one for Internet, you can get rid of one of them. However, the speed of your Internet connection may drop while you are talking on the phone.

Costs for DSL lines are higher than for regular phone lines, averaging $50 per month. There is usually a sign-up fee of several hundred dollars. The price for the Internet connection is generally a flat rate, but you are usually charged extra for voice calls, including local calls. You can order a DSL line through your ISP or directly from your phone company talk to both before you place your order. Availability depends on your location; DSL lines cannot be more than 18,000 feet (5,460 meters) from the phone company’s central office (or switching point for your exchange).
The phone company or ISP usually provides the DSL modem, which must match the DSL modem installed at their end. Because there are several competing DSL modem standards, not all DSL modems work with all DSL lines. If you already have a DSL modem, check with your phone company to find out whether you can save some money by using your own modem.

Terminal Emulation Program

You run a terminal-emulation program on your PC to connect to an Internet host computer Windows comes with HyperTerminal, a good terminal emulation program. Most Internet hosts run UNIX, a powerful but frequently confusing operating system, and you have to type UNIX commands to use a UNIX shell account. To send and receive e-mail or browse the Web, you run text-only programs, such as Pine and Lynx (the most widely used UNIX web browser). When you use a UNIX shell account, you do not see graphics or use a mouse, and you can’t easily store information on your own computer. For information about how to give commands once you are connected to a UNIX shell account.

Hardware and Software

Software

Here are examples of the required client software you will need:
  1. Operating system: An operating system (OS) provides the user interface and manages system resources such as disk drives and video cards. The operating system controls how the system operates overall.
    OSs are needed on both the client and the server, but they can be different types.
  2. TCP/IP software: Transmission Control Protocol/Internet Protocol (TCP/IP) is a communications protocol suite that lets dissimilar systems communicate. Every TCP/IP network client and server needs a unique IP address to identify it.
  3. Web browser: A client application used to browse, or "interface with," the Internet. Examples of browsers include Netscape Navigator and Microsoft Internet Explorer.
  4. Email: Electronic mail is a client application for transmitting mail over a network. Email is used as a worldwide communications tool.
In the next lesson, how to configure a Macintosh to access the Internet will be discussed.

Internet Infrastructure Quiz

Click the Quiz link below to reinforce your understanding of terms and concepts related to the Internet infrastructure.
Internet Infrastructure - Quiz