CSci 105

Introduction to Computers

Lecture 17

© Morris Firebaugh



I. Introduction

A. Continue Chapter 6 -- Networking

B. Data Communications - How It All Began

C. Putting Together a Network: A First Look

D. Data Transmission and Communication Links

E. Network Topologies

 


II. Data Communications

How It All Began

Convergence of communications and computers

 


III. Putting Together a Network

Getting Started

Three Basic Elements of Data Communications Systems

  1. A Sending Device
  2. A Communication Link
  3. A Receiving Device

Networks can be characterized by several parameters

Size

Network Topology

Network Speed

 


Data Transmission

Digital and Analog Transmission

The problem: How to send digital data by analog (telephone) signals?

Consider a sine wave:

y = 5 sin(x)

 

We may "modulate" this wave by changing its amplitude (AM):

 

We may also modulate it by changing its frequency (FM):

 

With proper electronics, the lower frequency may be considered a "0", the higher one a "1". The device to do this is called a modem.

 

 


IV. Communication Links (Hardware Technology)

Communication Technologies

 


V. Jargon of the Internet and WWW

The Internet itself is the best source of information on the Internet

http://www.neglobal.co.uk/webinfo/jargon.htm


VI. Features of Browsers

The Internet itself is the best source of information on Browsers

http://home.cnet.com/internet/0-3773.html

http://www.macupdate.com/internet.php?sub=1


VII. Features of Search Engines

The Internet itself is the best source of information on Search Engines

http://www.wi.net/links.html

http://www.yahoo.com/
http://www.altavista.digital.com/
http://www.google.com/


VIII. Research Using the Internet

Now, where is the best source of information on the Internet?

http://www.earthwatch.com/

http://www.stockmaster.com/

http://www.mapquest.com/

http://www.itn.net/cgi/get?itn/pl/amex_personal/index

 


IV. Laboratory Assignment #9

Click here

 





Updated March 8, 2001