Communications, Networks, the Internet, and the World Wide Web Teachers Discovering Computers Chapter 2 lecture 1 Communications, Networks, the Internet, and the World Wide Web

Chapter Objectives 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

Chapter Objectives Describe the World Wide Web portion of the Internet Explain 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

Chapter Objectives Explain how Internet services such as e-mail, newsgroups, chat rooms, and instant messaging work Describe the educational implications of the Internet and the World Wide Web Describe different ways to connect to the Internet and the World Wide Web

What Is Communications? A process in which two or more computers or devices transfer data, instructions, and information Sometimes called telecommunications What Is Communications?, 65 LECTURE NOTES Define communications, or telecommunications.

What Is Communications? Electronic mail (e-mail) Voice mail Fax (facsimile) Telecommuting Online services Videoconferencing Internet World Wide Web

Communications Networks Basic communications system Two computers, one to send and one to receive data Communications devices that send and receive data A communications channel over which data is sent CN: a collection of computers & other equipment organised to share data, info, hardware and software Communications Networks, 65 LECTURE NOTES Use Figure 2-1 to illustrate the basic model of a communications system. Define network and list the equipment needed. Define communications software and communications channel. Point out that communications channels are made up of one or more transmission media. Define transmission media. Explain how cabling media is different from wireless media. In anticipation of this section, obtain small samples of each cabling medium. For decades, telephone lines only were used to carry voice communications and used twisted-pair cables. This bandwidth is insufficient, however, for transmitting today’s graphics and computer signals. New buildings are being wired with fiber-optic cables, vastly improving their communications capabilities. Use Figure 2-2 to describe twisted-pair cable. Differentiate between digital signals and analog signals. The distinction between digital and analog signals can be compared to plucking a violin string (digital) versus playing a violin with the bow (analog). Explain the function of a modem using Figures 2-3a and 2-3b. Remind students why it is necessary to convert between digital and analog signals. Define modem. Emphasize that modems are necessary at both the sending and receiving end. In the 1970s, modems could transmit a 100-word paragraph in 10 to 15 seconds. Today modems can send 30,000 single-spaced, typewritten pages in one second — faster than a speeding bullet. The de facto standard in modems is Hayes. Many modems are advertised as “Hayes compatible”. Define internal modem and discuss the use of cable and DSL modems to connect to the Internet.

Communications Networks

Communications Networks Communications channel Transmissions media Twisted-pair cable e.g. Tel lines in the home

Communications Networks Digital signals: individual electrical pulses that a computer uses to represent data Analog signals: a continuous electrical wave (e.g. tel equip) Modem External modem Internal modem Network interface cards

Communications Networks Local Area Networks (LAN) Covers limited geographical area (e.g. school, office, building) Server manages resources & is a centralized storage area Wide Area Networks (WAN) Covers large geographical area (e.g. city, school district) Can consist of several LANs Local Area Networks, 68 LECTURE NOTES Define local area network (LAN). Define server and wireless LAN (WLAN) and explain how servers are used in schools. Wide Area Networks, 68 Define wide area network (WAN). Explain the difference between LANs and WANs.

Communications Networks Home Networks Connects multiple computers in your home Share Internet access Share peripherals Can be wired or wireless Home Networks, 68 LECTURE NOTES Use Figure 2-5 to discuss how a home network works. Discuss the advantages of setting up a home network.

Networking the Classroom, School, and District School network server connects all computers located within the school E.g. in the classroom Three Macintosh computers Printer All connected to school’s LAN Networking the Classroom, School, and District, 69 LECTURE NOTES Explain how and why K-12 schools and school districts are installing high-speed networks. Remind the students of the impact of the E-Rate discount program on schools and libraries (discussed in Chapter 1, page 23). Using the examples provided in Figures 2-6, 2-7, and 2-8, explain how a school district networks its classrooms, schools, and district. Use these examples to again show the difference between a LAN and WAN. Use the Web Info on school networks for more information.

E.g. School network: Classrooms; Administration; Computer lab

E.g. School district: Central office; various schools

Networking the Classroom, School, and District Wireless schools and classrooms Keep in touch with family and friends from anywhere Smart phones Handheld or netbook computers Notebook computers Wireless technology brings the computer lab to students

The Benefits of Computer Networks in Education Sharing of computer hardware, software, and data resources Unlimited educational resources Communicate with other educators and students The Benefits of Computer Networks in Education, 73 LECTURE NOTES The benefits of networking school computers are substantial. Review the various benefits with your students. Discuss Figure 2-10.