1. Topics Lesson 7 Basic Telecommunication Concepts
Telecommunication Models
Networking
Client/server Computing
Telecommunication Standards
Wireless Communications
Internet

2. Modems Baud - transfer rate (bits per second)
Analog signals: continuous
Digital signals: discrete
Modulation: translating digital data to analog
Demodulation: translating analog data to digital
Modems modulate & demodulate data
Fax/Modem
telephone as well as facsimile
Often, data is sent over the regular telephone network, which transmits analog signals. An analog signal is a continuous signal; the transmission line varies smoothly among an infinite number of states. Analog waves can carry a continuous range of data. On the other hand, computers produce digital signals. Digital signals send discrete pulses and represent a limited number of states. In the case of a computer, two states are represented. In order to send a digital signal over an analog line, the signal must first be modulated, or changed to a form that can be carried over an analog line. When the signal is received, it must be demodulated so the computer can understand it. This is what a modem does.

3. Modems
A typical telephone line can only accommodate an analog signal (a continuous, curving signal)
A computer generates a digital signal representing bits
Modem: a device that translates data from digital to analog and analog to digital

4. An Overview Of Telecommunications
Figure 6.1: Elements of a Telecommunications System
Principles of Information Systems, Eighth Edition

5. Telecommunications Hardware
Figure 6.6: How a Modem Works
Principles of Information Systems, Eighth Edition

6. Data Flow Simplex Half Duplex Full Duplex one way both directions
both directions at the same time

7. Multiplexers
Multiplexers: devices that allow several telecommunications signals to be transmitted over a single communications medium at the same time

8. Use of a Multiplexer to Consolidate Data Communications onto a Single Communications Link

9. Front-End Processors
Front-end processors: special-purpose computers that manage communications to and from a computer system
Connect a midrange or mainframe computer to hundreds or thousands of communications lines

10. Front-End Processor

11. Telecommunications Media
Communications media carry

12. Connections Micro to micro (modem) Terminal to computer (direct)
Micro to micro (direct)
LAN

13. Fig 6.19
In a terminal-to-host configuration, users have dumb terminals connected to a host computer. All file access and processing is done on the host.

14. Types of Media Twisted Pair Coaxial Cable Fiber-Optic Cable
Microwave Transmission
Different kinds of communications media have different characteristics, including different speeds and capacities. As with other components of an information system, the choice of medium depends on the purpose of the telecommunications system within the information system. The media selected should be the most adaptive, cost effective media that support these objectives. Media is critical in determining the overall system’s efficiency and effectiveness.
The first 3 types of media – twisted pair, coaxial cable, and fiber optic cable – are usually referred to as guided or conducted media. That is, a signal is conducted over a physical medium. Microwave and other forms of wireless transmission are called broadcast media. Generally speaking, there are fewer errors in guided than in broadcast media.

15. Twisted Pair
Fig 6.4
Twisted pair cabling is made of pairs of copper wires twisted together. Twisted pair is used for the phone connection to your house. In networking it is common to see cable consisting of 4 pairs of wires. Each pair is twisted together to reduce electrical interference between neighboring pairs, or crosstalk. The more twists there are per foot, the less interference there will be. Twisted pair is classified by the number of twists per foot. Data grade cable has more twists per foot than does voice grade cable.
Shielded twisted pair cabling includes additional shielding against external electro-magnetic interference. Unshielded twisted pair, although it doesn’t have the extra shielding, is used more often because of its lower costs and greater practicality.

16. Coaxial Cable
Fig 6.5
Like twisted pair, coaxial cable, or “co-ax”, is also made from copper. However, because of extra shielding and insulation, coax has less interference, and therefore a higher capacity, or bandwidth, than does twisted pair. Data can be sent over coax at about 500 Mbps, whereas data transmission speeds over twisted pair for long distances are typically well below that, although in a local area network fast speeds can be attained using twisted pair.
A type of coaxial cable is used for cable TV to your home. Cable modems can be used for Internet access several hundreds as times as fast as a modem and dial-up phone line.

17. Fiber Optic Cable
Fig 6.6
Unlike twisted pair and coax, fiber optic cable is made of thin filaments of glass or plastic, not of copper wire. Whereas a data signal travels over twisted pair or cable as electricity, signals are transmitted as light pulses over fiber. Lasers or LCDs produce the light. A thin coating, called cladding, prevents the light from leaving the strand. Also unlike copper media, fiber is not vulnerable to electro-magnetic interference.
Fiber has a much higher bandwidth than does copper media – that is, it can carry more data faster. Fiber can have a capacity of billions of bits per second. Fiber is also the most secure medium around today. The biggest drawback of fiber is that labor costs to install and repair fiber are very high.

18. Microwave Transmission
Fig 6.7
The expense of physical media can be great. Whereas broadcast media, such as microwave, don’t require the purchase of physical media, the hardware required is more expensive. Microwave is a high frequency radio signal.
In terrestrial microwave, a signal travels directly between microwave transmission towers. This requires an unobstructed straight path between towers. Also, due to the curvature of the earth, towers must be spaced about 30 miles apart.

19. Satellite
Fig 6.8
Satellite transmission involves sending a signal from a microwave tower to the satellite, which is basically a microwave station, then back to another microwave tower. Although this eliminates the need for a line-of- sight between towers, the delays to upload and download the signal often make satellite transmission impractical for sending signals short distance.

20. Infrared Transmission
Line of sight
Short distances
Infrared transmission can be used to send data short distances, for example, from a handheld computer to a desktop or a printer. Infrared transmission can also be used to connect peripherals, such as a mouse, to a computer.

21. Local Area Networks
Server Based
Peer-to-Peer

22. Lan Topology
Star
Bus
Ring
Hierarchical

23. The Basic Network Topologies

24. Other
Gateway
WAN
Wireless

25. Wireless Communications Protocols
Wi-Fi
WiMAX
Smart antenna technology
Ultra Wideband (UWB)
3G wireless communication
4G wireless communications
Principles of Information Systems, Eighth Edition

26. Wireless Communications Protocols (continued)
Table 6.14: Wi-Fi Network
Principles of Information Systems, Eighth Edition

27. Wireless Communications Protocols (continued)
Switch: uses physical device address in each incoming message to forward message to another device on the same network
Bridge: connects one LAN to another LAN that uses the same telecommunications protocol
Router: forwards data packets across two or more distinct networks toward their destinations through routing
Gateway: serves as an entrance to another network
Principles of Information Systems, Eighth Edition

28. What Is Client/Server?
Client/server is a term used to describe a computing model for the development of computerized systems. This model is based on the distribution of functions between two types of independent and autonomous processes; servers and clients.
A client is any process that requests specific services from server processes.
A server is a process that provides requested services for clients.
The key to client/server power is where the requested processing takes place. 4

29. Basic Client/Server Computing
What Is Client/Server?
Basic Client/Server Computing 5

30. The Forces That Drive Client/Server Systems
Changing Business Environment
Global competition.
Need for fast, efficient, and widespread data access.
Need for Enterprise-Wide Data Access
End User Productivity Gains Based on the Use of Data Resources
Technological Advances
Microprocessor technology, Data communications and LANs, DB systems, OS and GUIs, Sophisticated PC-based end user application software.
Cost/Performance Advantages of the PC-Based Platform 6

31. The Evolution of Client/Server IS
Mainframes in the 1970s
Complex, proprietary OS
Dumb terminals
Restricted access
Hardware and software dictated IS
Centralized, complex MIS department bureaucracy
Microcomputers in the 1980s
Easy-to-use software (e.g., spreadsheet)
Micro-based database systems
Data still in mainframes
“Manual download” 7

32. The Evolution of Client/Server IS
Intelligent Terminals
PCs connected to the mainframe
Electronic download
Proliferation of snapshot versions of corporate DB
Islands of information
Sneaker net
Local Area Network
Network operating systems (NOS)
Powerful PCs
Common platform for both end users and MIS specialists 8

33. Client/Server Systems Benefits
Client/Server Benefits
Platform-independent system development
Optimized distribution of processing activities among different platforms
Use of user friendly, cost effective, and compatible techniques, methodologies, and specialized tools 11

34. Managerial Expectations of Client/Server Systems Benefits
Organizational Expectations of Client/Server Benefits
Flexibility and adaptability
Improved employee productivity
Improved company work flow and a way to re-engineer business operations
New opportunities to provide competitive advantages
Increased customer service satisfaction 13

35. Client/Server Architecture
Components of Client/Server Architecture
Client. The client is any computer process that requests services from the server. It is also known as the front-end application.
Server. The server is any computer process providing services to the clients. The server is also known as the back-end application. 14

36. Client/Server Architecture
Client Components
Powerful hardware
An operating system capable of multitasking
A graphical user interface (GUI)
Communications capability 18

37. Client/Server Architecture
Server Components
File services
Print services
Fax services
Communications services
Database services
Transaction services
Miscellaneous services 20

38. Telecommunication Standards
TCP/IP Transmission Control Protocol/Internet Protocol
standardized naming conventions .com .edu .gov .org
Integrated Services Digital Networks (ISDN)
transmission of voice, data, and video on the same line (two 64KB channels & one 16KB channel)

39. The Internet, Intranets, and Extranets
Chapter 7, The Internet, Intranets, and Extranets, covers the Internet and its use and effects.
After studying chapter 7, you should be able to address the learning objectives described in the next 3 slides.

40. Use and Functioning of the Internet
The Internet is an international collection of computer networks connected together by routers. Devices use specific protocols to communicate over the Internet and individuals and business access it through Internet Service Providers, or ISPs.

41. The Internet is pervasive will it collapse as it expands?
35 million users (1996)
163 million users (2000)

42. What is the Internet
a global set of interconnected data networks running the TCP/IP protocols
Traditional services include , file transfer (FTP); current focus is on the World Wide Web
Largely self-financing; no single point of control or administration (ANARCHY)

43. How the Internet Works Hosts Routers forward packets to other networks
Internet Protocol Stack (TCP/IP)
Internet Protocol (IP)
Transport Control Protocol (TCP)
Backbones
Computers on the Internet, whether mainframes or PCs, are called hosts. Routers forward messages in pieces, called packets, on the Internet, from one network to another, using the Internet Protocol. When a host sends a message to a computer on a different network, it goes first to a router. The router sends it to another network, where another router may pass it on. All networks connected to the Internet use the Internet Protocol stack, also called TCP/IP. IP is the network layer protocol that helps route packets from one network to another. TCP, Transport Control Protocol, is one of several other protocols included in the Internet Protocol stack used by most hosts on the Internet.
Networks using TCP/IP standards connect to one of the Internet’s fast, long distance communications links, a backbone, to communicate with other networks on the Internet.

44. How the Internet Works http://www.whitehouse.gov
Uniform Resource Locator(URL)
World Wide Web
Domain category
Hypertext transfer protocol
Host Network Name
Each host on the Internet has been assigned a unique address to distinguish it from other computers on the Internet. The address is a long sequence of numbers – easy for computers and routers to process, but hard for people. Unique logical names, called URLs, or uniform resource locators, are also assigned to correspond with the numeric address, making it easier for people to remember.
Consider the URL for the White House, The “http” signifies a specific Internet protocol used by most web browser and web server software. The “www” means this site is part of the “World Wide Web”, one of several Internet services. “Whitehouse.gov” is the domain name. Domain names follow specific rules. Dots separate the components of the address, and there will be at least two components, as in whitehouse.gov. With the exception of most US domain names, the rightmost part is typically a country designator. For example, the National Library of Australia has the URL where “au” designates Australia. The leftmost part of the domain name identifies the host network, such as “nla” or “whitehouse”. The rightmost part of a US domain name (and the part next to the country code for a non-US name) designates the category, or type, of the site. Here, the category is “gov”, for government.

45. Table 7.2: U.S. Top-Level Domain Affiliations
How the Internet Works
Table 7.2: U.S. Top-Level Domain Affiliations
Principles of Information Systems, Eighth Edition

46. How the Internet Works (continued)
Figure 7.1: Routing Messages over the Internet
Principles of Information Systems, Eighth Edition

47. Structure of the Internet
National/global backbone networks
Network Access Points (NAPS) connecting the major commercial backbones
Internet Service Providers (ISPS)
“wholesale”:selling access to Users and other ISPS
“retail”:resell access to someone else's backbone

48. Figure 7.3: Several Ways to Access the Internet
How the Internet Works
Figure 7.3: Several Ways to Access the Internet
Principles of Information Systems, Eighth Edition

49. The World Wide Web
The World Wide Web was originally developed as an internal document management system. It has grown to a huge, global collection of independent computers, or web servers, and is the most famous Internet service. Using hypertext links, or hypermedia, a type of cross-indexing tool, users can jump from one web server to another immediately. To the user, the entire web is like one giant computer. You can jump from a page on one web server to a page on a related topic that is stored on the other side of the world. Hypertext links are maintained using URLs. A URL is the logical address, such as that you type in your browser when going to a website. Web pages on web servers can contain data in any format – from ASCII characters to video images.

50. The World Wide Web World Wide Web: AKA the Web, WWW, or W3
A menu-based system that uses the client/server model
Organizes Internet resources throughout the world into a series of menu pages, or screens, that appear on your computer
Hypermedia: tools that connect the data on Web pages, allowing users to access topics in whatever order they wish

51. The World Wide Web (continued)
Hypertext Markup Language (HTML): the standard page description language for Web pages
HTML tags: inform browsers how to format text on a Web page, and whether images, sound, and other elements should be inserted
Extensible Markup Language (XML): markup language for Web documents containing structured information, including words, pictures, and other elements

52. Html and XML Demo

53. Figure 7.4: Sample Hypertext Markup Language
The World Wide Web
Figure 7.4: Sample Hypertext Markup Language
Principles of Information Systems, Eighth Edition

55. Web Browsers
Web browser: software that creates a unique, hypermedia-based menu on a computer screen, providing a graphical interface to the Web
Menu consists of graphics, titles, and text with hypertext links
Popular Web browsers: Microsoft Internet Explorer, Netscape Navigator, Mozilla Firefox, Apple Computer’s Safari
Applet: small program embedded in Web pages
Web browser plug-in: external program that is executed by a Web browser when it is needed
Principles of Information Systems, Eighth Edition

56. Search Engines and Web Research
Search engine: Web search tool
Examples: Yahoo.com, Google.com
Most search engines are free
Searches can use words, such as AND and OR to refine the search
Meta-search engine: submits keywords to several individual search engines and returns results from all these search engines
Principles of Information Systems, Eighth Edition

57. Search Engines and Web Research (continued)
Table 7.6 Popular Search Engines
Principles of Information Systems, Eighth Edition

58. Webcasting aka Push Technology
Consolidates information according to a user’s profile & displays in the browser
Although users can search for sites on the Internet, push technology can automatically provide customized content to individuals. Webcasting, or push technology, gathers information and brings it to the client computer.

59. Web Programming Languages
Java
Object-oriented programming language from Sun Microsystems based on C++
Allows small programs (applets) to be embedded within an HTML document
Principles of Information Systems, Eighth Edition

60. Web Programming Languages
Java
Object-oriented programming language from Sun Microsystems based on C++
Allows small programs (applets) to be embedded within an HTML document
Principles of Information Systems, Eighth Edition

61. Web Programming Languages (continued)
Other programming languages used to develop Web sites
JavaScript
VBScript
ActiveX
Hypertext Preprocessor (PHP)
Principles of Information Systems, Eighth Edition

62. Internet Services
The Internet has impacted business and individuals because of the many uses and services it provides.

63. Web Services
Web services: standards and tools that streamline and simplify communication among Web sites for business and personal purposes
XML is used within a Web page to describe and transfer data between Web service applications

64. Web Services (continued)
Besides XML, other components are used in Web service applications:
SOAP (Simple Object Access Protocol)
WSDL (Web Services Description Language)
UDDI (Universal Discovery Description and Integration)

65. Internet and Web Applications
The types of Internet and Web applications available are vast and ever expanding
Principles of Information Systems, Eighth Edition

66. E-Mail, Instant Messaging, and Push Technology
No longer limited to simple text messages
Can embed sound and images
Can attach files
Instant messaging: online, real-time communication between two or more people who are connected to the Internet
Push technology: automatic transmission of information over the Internet rather than make users search for it with their browsers
Principles of Information Systems, Eighth Edition

67. E-Mail, Instant Messaging, and Push Technology (continued)
Table 7.7: Some Common Abbreviations Used in Personal
Principles of Information Systems, Eighth Edition

68. Internet Cell Phones and Handheld Computers
Cell phones connected to the Internet allow people to search for information, buy products, and chat with business associates and friends
Short Message Service (SMS) or texting
Brief text messages can be sent between two or more cell phone users
Handheld computers and other devices are connected to the Internet using phone lines or wireless connections
Principles of Information Systems, Eighth Edition

69. Career Information and Job Searching
Use search engines to look for specific companies or industries
Internet sites specialize in helping you find job information and apply for jobs online
Examples: and
Principles of Information Systems, Eighth Edition

70. Internet Phone and Videoconferencing Services
Internet phone service
Relatively inexpensive, especially for international calls
Voice-over-IP (VoIP) technology
Network managers can route phone calls and fax transmissions over the same network they use for data
Internet videoconferencing
Supports both voice and visual communications
Webcasts or Webinars
Principles of Information Systems, Eighth Edition

71. How Voice Over IP Works

72. Content Streaming
Method for transferring multimedia files, radio broadcasts, and other content over the Internet
Data stream of voice and pictures plays more or less continuously without a break, or with very few breaks
Enables users to browse large files in real time
Works best when the transmission of a file can keep up with the playback of the file
Principles of Information Systems, Eighth Edition

73. Shopping on the Web You can shop for almost anything over the Internet
Convenient, easy, and cost effective
Many Web sites also offer free shipping and pickup for returned items
Bot: a software tool that searches the Web for information, products, or prices
Finds the best prices or features from multiple Web sites
Principles of Information Systems, Eighth Edition

74. Web Auctions
Web auction: Internet site that matches buyers and sellers
Businesses grow or reach customers for a low cost per transaction
One of the most popular auction sites: eBay
Potential problems with auction Web sites
Auction sites cannot always determine whether the people and companies listing products and services are legitimate
Some Web sites have illegal or questionable items offered
Principles of Information Systems, Eighth Edition

75. Music, Radio, Video, and TV on the Internet
Audio and video programs: play on the Internet or download files for later use
Music players and music formats such as MP3: download music from the Internet and listen to it anywhere
Musicians can gain exposure without a lucrative music contract
Radio broadcasts
Audio books
Principles of Information Systems, Eighth Edition

76. Intranets and Extranets
An intranet is an internal organizational network that uses Internet and World Wide Web standards and technologies. An intranet can be local or may connect all of a corporation’s worldwide resources. These private networks are used to provide employees or other internal users information and to handle administrative tasks. For example, in some firms employees can complete and file forms such as travel reports over the intranet. Since so many people are familiar with the Internet and World Wide Web, they need little help in using intranets effectively. Intranets are integrating computers, software and databases that are dispersed throughout businesses together – a feat that has eluded technologists and managers until now.
An increasing number of organizations are offering limited access to their intranet to specific customers or suppliers. These networks, called extranets, connect external people to those in the company, based on the technologies of the Web.

77. Intranets and Extranets
Internal corporate network built using Internet and World Wide Web standards and products
Slashes the need for paper
Provides employees with an easy and intuitive approach to access information that was previously difficult to obtain

78. Intranets and Extranets (continued)
Extranet: a network based on Web technologies that links selected resources of a company’s intranet with its customers, suppliers, or other business partners
Virtual private network (VPN): a secure connection between two points across the Internet
Tunneling: the process by which VPNs transfer information by encapsulating traffic in IP packets over the Internet

79. Summary of Internet, Intranet, and Extranet Users

80. Virtual Private Network

81. Net Issues
All types of networks – the Internet, intranets, extranets, LANs and WANs - are all affected by control, access, hardware and security issues. Since there is no central governing body for the Internet, issues such as privacy or offensive or sensitive material being placed on the Internet are difficult to address. These issues are easier to deal with for corporate networks.

82. Net Issues Management issues: preventing attacks
Service and speed issues
Web server computers can be overwhelmed by the amount of “hits” (requests for pages)
Routers can become bottlenecks

83. Net Issues (continued)
Privacy
Spyware: hidden files and information trackers that install themselves secretly when you visit some Internet sites
Cookie: a text file that an Internet company can place on the hard disk of a computer system
Fraud
Phishing

84. Net Issues (continued)
Security with encryption and firewalls
Cryptography: converting a message into a secret code and changing the encoded message back to regular text
Digital signature: encryption technique used to verify the identity of a message sender for processing online financial transactions
Firewall: a device that sits between an internal network and the Internet, limiting access into and out of a network based on access policies
Unauthorized sites

85. Cryptography process

86. Internet Security Contracts & Process relationships Examples
Digicash;Cybercash,Mondex,Secure Link, Open Exchange
Catalog industry (3 billion $ shift)

87. Electronic Payment Methods Components
Broad acceptance
Customer anonymity (as needed)
Payment input mechanisms
Point of sale readers, smart cards, PCs

88. with Efficient Electronic Payments
Anyone with a computer & a telephone can become a small business
Cost of entry and ease of entry is becoming very low

89. New Organizations are Emerging
“Virtual Corporations”
Increasing usage of consultants; temporary employees
Telecommuting

90. Business Implications
20-25% of 100 Fortune 500 companies will not exist due to the Internet
Borderless trade
Language, culture and other imponderables

91. Questions (?)