1. 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

2. 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

3. 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

4. Chapter Objectives
Explain how Internet services such as , 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

5. 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.

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

7. 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.

8. Communications Networks

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

10. 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

12. 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.

13. 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.

14. 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.

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

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

17. 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

18. 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.