COMPUTERS IN THE CLASSROOM CT 243 Emery Roth eroth hartford edu http uhaweb hartford edu eroth CHAPTER 2 Communications Networks th by rjz61441


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        CT 243

                       Emery Roth
 Networks, the
Internet, and the
World Wide Web
What are the two
main categories of
and how are they
different? (1.13-1.14)
What are the “National
Educational Technology
Standards for Teachers”
(NETS-T), and where do
they come from? (1.19-1.20)
What is a “motherboard,”
what are its two main
components? (1.08)
What are 5 components
of a computer?
…and give examples of
each. (1.07-1.10)
What is, “the Internet,”
what are several ways it
is useful for teachers?
     Click on “Chapter 1”
 From the menu on the left,
 select “Integration Corner,”
       then “chapter 1”
 Scroll to any level of personal
interest & explore one resource
  1.    Gather by teams to regroup
  2.    Read at least 3 sketches.
  3.    Select group recorder (WP).
  4.    Process:
       • I really liked…
       • I learned to…
       • How do I…?
       • Publish???
To publish or not
  to publish…
          Drawing Tablet

• pressure-sensitive
• designed to work with software applications that
  simulate real artists’ media
  posted on blackboard & web site

          Web site:
 Networks, the
Internet, and the
World Wide Web
 Define communications
 Identify the basic components of a communications system
 Describe how and why network computers are used in
  schools and school districts
 Explain how the Internet works
 Describe the World Wide Web portion of the Internet
 Specify how Web documents are linked to one another
 Explain the use of Web browser software
 Explain how to use a Web search tool to find information
 Identify several types of multimedia products available on
  the Web
 Explain how Internet services such as e-mail, newsgroups,
  chat rooms, and instant messaging work
 Describe how to connect to the Internet and the WWW
         Communications Networks
 Communications - refers to the transmission of data
  and information between two or more computers
  using a communications channel such as standard
  telephone lines
 Communications network - is a collection of
  computers and other equipment organized to share
  data, information, hardware, and software
 Communications software - programs that manage the
  transmissions of data between computers
 Communications channel - is the path the data follows
  as the data is transmitted from the sending equipment
  to the receiving equipment in a communications
  Communications Networks Continued
 Transmission media - is the physical
  materials or other means used to establish a
  communications channel
     Twisted-pair cable - consists of pairs of plastic-
      coated copper wire twisted together
     Other examples (coaxial cable, fiber-optic
      cable, microwave transmission,
      communications satellites, and wireless
 Communications Networks Continued
 Digital signals - are individual electric pulses
  that a computer uses to represent data
 Analog signals - continuous electrical wave
  used for telephone transmission and other
 Modem - converts analog signals into digital
 Network interface card (NIC) - connects
  computers directly to a school or business
  network without using a modem
                Types of Networks
 Local area networks (LAN) - is a communications
  network that covers a limited geographical area such
  as a school, an office, a building, or a group of
 Wireless LAN (WLAN) - uses no wires, instead it
  uses wireless media, such as radio waves.
 Wide area networks - covers a large geographical
  region and used regular telephone cables, digital lines,
  microwaves, wireless systems, satellites, or other
  combinations of communications channels.
 Home networks - if you have multiple computers in
  your home or home office you can create your own
           History of the Internet
 ARPANET - Advanced Research Projects Agency
    allow scientists to share information

    parts could function even if some of it went down

    Established 1969 and by 1984 it had 1,000 hosts

 In 1986 NSFnet joined together with ARPANET to
  serve as the backbone of the Internet
 In 1995 NSF turned over responsibilities to major
 Internet2 - extremely high speed network that will
  develop and test advanced Internet technologies for
  research, teaching, and learning.
          How the Internet works
 Step 1. Data is divided into small pieces, called
 Step 2. Packets travel over the Internet via routers.
 Step 3. At the destination, the packets are
  reassembled into the original message.
      Packet switching
 TCP/IP - transmission control protocol/Internet
  protocol - protocol used to define packet switching
          ISP vs. OSP vs. WSP
 Internet service provider (ISP) - allows you to
  connect to the internet for a fee. (ex. Netzero,
 Online service provider (OSP) - allows you to
  connect to the internet and also provides other
  personalized options for a higher fee than an ISP
 Wireless service provider (WSP) - allows users to
  connect to the internet without any wires. (ex.
     Ways to Connect to the Internet

 Dial-up access - you use your computer and
  a modem to dial in to the internet. (56k)
 Cable modem - you use your existing tv
  cable and a cable modem (20-50 x faster)
 Digital subscriber line - you use digital
  phone lines and dsl card. (25-150 x faster)
             Internet Backbone
 Step 1: Request a web page from your home computer
 Step 2: Modem converts digital to analog
 Step 3: Data travels through telephone lines to local
 Step 4: Data may travel through 1 or more routers
 Step 5: Regional ISP uses lines, leased from a
  telephone company, to send data to a national ISP
 Step 6: A national ISP routes data across the country
  to another national ISP
 Step 7: Data moves from a national ISP to a local ISP
  to a server that contains the requested site
 Step 8: The server requests the data and sends it back
  through the internet.
                 Internet Addresses
 The Internet uses addresses the same way the post
  office does. Each computer has a specific numeric
 Domain name - the text version of a computer
 Domain abbreviations - .com, .edu, .gov, .mil,
  .net, .org, .k12
 Country abbreviations
      Au - Australia; CA - Canada; UK - United Kingdom
             World Wide Web
 The Web - consists of electronic documents that
  have built in hyperlinks to other related documents
 Hyperlinks - allow users to navigate quickly from
  one page to another
 Web page - electronic document viewed on the
  Web that can contain audio, video, text, etc.
   Web site - a collection of related web pages
   Home page - starting point of a web site
   URL - uniform resource locator
   HTTP - hypertext transfer protocol
       How a Web Page Works
 Three types of hyperlinks exist
     Target hyperlinks - links within the same page
     Relative hyperlinks - link to another document
      on the same Internet computer (server)
     Absolute hyperlinks - link to another document
      that could be located on a computer across the
 HTML - hypertext mark-up language - the
  code that defines what a website will look
      Web Browser Software

 A web browser is a program that interprets
  HTML and displays Web pages and allows
  links to other pages
 Mosaic - developed in 1993 by Marc
  Andreesen, a student at the University of
 Netscape, Internet Explorer, AOL, Safari
Searching for Info. on the Web
 Search tools - enable users to locate information
  found at Web sites all over the world
 Search engine - a type of search tool that uses
 Subject directory - a type of tool that allows the
  user to navigate the directories and subdirectories
           Multimedia on the Web
 Multimedia is the combination of graphics,
  animation, audio, video, and virtual reality
 Graphics - were the first media used to enhance
  text only sites
 Animation - is the appearance of motions created
  by displaying a series of still images in rapid
 Audio - you can listen to prerecorded audio clips
  and live audio
 Video - consists of full motion images that are
  played back at various speeds
 Virtual reality - is the simulation of a real or
  imagined environment
 E-mail (electronic mail) - is the
  transmission of messages and files via a
  computer network
 E-mail program - allows you to compose,
  view, send, and receive email
 E-mail address - is a combination of a user
  name and a domain name
File Transfer Protocol
 FTP - is an Internet standard that allows you
  to exchange files with other computers on
  the Internet.
 Anonymous FTP - anyone can transfer files
  on this type of site.
     Information Sharing via the Web
 Newsgroup - is an online area in which users
  conduct written discussions about a particular
 Mailing list - is a group of email addresses given a
  single name
 Chat rooms - is a real-time typed conversation
 Instant messaging - is real-time Internet
  communications service that notifies you when
  one or more people are online.
 Netiquette - is the code of acceptable behavior
  while on the Internet
Interesting Sites

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