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Technology Guide 4 Telecommunications and the Internet T4-1.

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1 Technology Guide 4 Telecommunications and the Internet T4-1

2 IT for Management Prof. Efraim Turban T4-2 Telecommunication Concepts Telecommunication –long-distance communication through the use of common carriers, including telephone, television, and radio. Data Communications –Electronic collection, exchange, and processing of data or information, including text, pictures, voice, and other information that is digitally coded and intelligible to a variety of electronic machines

3 IT for Management Prof. Efraim Turban T4-3 Telecommunication System Host Computer Host Computer PC or Terminal PC or Terminal Multiplexor Modem Host Computer Host Computer PC or Terminal PC or Terminal Multiplexor Modem Hardware Front end processor Receiver Telecommunication media (channels)

4 IT for Management Prof. Efraim Turban T4-4 Electronic Signals Analog Signals –continuous waves that “carry” information by altering the characteristics of the waves –amplitude and frequency Digital Signals –discrete on-off pulses that convey information in terms of 1s and 0s, just like the central processing unit in computers

5 IT for Management Prof. Efraim Turban T4-5 Database and Database Management Systems Database –an organized logical grouping of related files –no data redundancy, data isolation, and data inconsistency Database Management Systems (DBMS) –a program that provides access to a database –permits an organization to centralize data, manage them efficiently, and provide access to the stored data by application programs

6 IT for Management Prof. Efraim Turban T4-6 Communication Processors Modem –Performs modulation and demodulation –Modulation convert information from digital to analog –Demodulation convert information form analog to digital

7 IT for Management Prof. Efraim Turban T4-7 Communication Processors Multiplexor –An electronic device that allows a single communications channel to carry data transmissions simultaneously from many sources Front-end Processor –A specialized computer that managers all routing communications with peripheral devices

8 IT for Management Prof. Efraim Turban T4-8 Communications Media (Channels) Cable Media –Twisted-pair wire consists of strands of copper wire twisted in pairs –Coaxial cable consists of insulated copper wire, and is much less susceptible to electrical interference and can carry much more data than twisted-pair wire –Fiber Optics consists of thousands of very thin filaments of glass fibers –Photonics generates and harnesses light and other forms of radiant energy whose quantum unit

9 IT for Management Prof. Efraim Turban T4-9 Communications Media (Channels) Wireless Media –Microwave –Satellite geostationary earth orbit (GEO); medium earth orbit (MEO); and low earth orbit (LEO) –Global Positioning Systems –Radio –Infrared

10 IT for Management Prof. Efraim Turban T4-10 Communications Media (Channels) Wireless Media –Cellular Radio Technology Wireless Application Protocol (WAP); Wireless Markup Language (WML) –Mobile Computer –Personal Communication service –Personal Digital Assistants

11 IT for Management Prof. Efraim Turban T4-11 Characteristics of Communication Media Transmission Speed –bandwidth : the range of frequencies available in any communications channel –bit per second (bps) : the unit of measurement –channel capacity : narrowband, voiceband, and broadband –baud rate : the amount of data that can be transmitted through a communications channel Optical Networking –dense wave division multiplexing (DWDM)

12 IT for Management Prof. Efraim Turban T4-12 Transmission Direction Simplex Data Transmission –uses only one direction only Half-duplex Transmission –uses only one circuit, but it is used in both directions Full-duplex Transmission –uses two circuit for communications – one for each direction simultaneously

13 IT for Management Prof. Efraim Turban T4-13 Transmission Mode Asynchronous Transmission –only one character is transmitted or received at a time –inherently inefficient Synchronous Transmission –a group of characters is sent over a communications link in a continuous bit stream while data transfer is controlled by a timing signal initiated by the sending device

14 IT for Management Prof. Efraim Turban T4-14 Transmission Accuracy Telephone line cables may be mishandled by repair personnel, accidentally cut by construction workers, or subjected to power surges while data are being transmitted. Accuracy controls consist of bits called parity bits that are like check sums aded to characters and/or blocks of characters at the sending end of the line.

15 IT for Management Prof. Efraim Turban T4-15 Protocols Protocol is a set of rules and procedures governing transmission across a network Transmission Control Protocol/Internet Protocol (TCP/IP) is a file transfer protocol that can send large files of information n across sometimes unreliable networks with assurance that he data will arrive in uncorrupted form

16 IT for Management Prof. Efraim Turban T4-16 Communication Standards Network Standards –physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer –System Network architecture (SNA) standard Transmission Standards –fiber distributed data interface (FDDI), asynchronous transfer mode (ATM), switch hub technologies, and Integrated services digital network (ISDN) Software Standards –Operating systems, graphical user interface standard, software application standards

17 IT for Management Prof. Efraim Turban T4-17 Interfaces Parallel Data Transfer –most often used for local communication, employs a communications interface with a series of dedicated wires, each serving one purpose –both data and control signals are transmitted simultaneously Serial Data Transfer –most often used for long-distance communications, is bit by bit rather than many bits in parallel

18 IT for Management Prof. Efraim Turban T4-18 Network Topology Bus Network –nodes are arranged along a single length of twisted-pair wire, coaxial cable, or fiber optic cable that can be extended at he ends Rink Network –nodes are arranged along the transmission path so that a signal passes through one station at a time before returning to its originating node Star Network –a central node that connects to each of the other nodes by a single, point-to-point link

19 IT for Management Prof. Efraim Turban T4-19 Local Area Networks (LAN) LAN connects two or more communicating devices within a short distance –Gateway is a communications processor that can connect dissimilar net works by translating for one set of protocols to another –Bridge connects two networks of the same type –Router routes messages through several connected LANs or to a WAN Private Branch Exchange (PBX)

20 IT for Management Prof. Efraim Turban T4-20 Wide Area Networks (WANs) Value-Added Networks (VAN) –private, multipath, data-only, third-party- managed networks that can provide economies in the cost of service and network management Frame Relay –a shared network service that packages data into “frames” that are similar to packets Virtual Private Network (VPN) –a set of hardware and software that provides a gateway between a corporate LAN and the internet

21 IT for Management Prof. Efraim Turban T4-21 Network Processing Point-to-Point Connection –two devices on a network are directly connected Peer-to-Peer Connection –two devices have the same relative standing, as with two microcomputers

22 IT for Management Prof. Efraim Turban T4-22 Client/Server Architecture Presentation Component –the application interface or how the application appears to the user Applications Logic –created by the business rules of the application Data Management Component –consists of the storage and management of the data needed by the application

23 IT for Management Prof. Efraim Turban T4-23 Types of Client/Server Architecture Distributed Presentation Remote Presentation Distributed Function Remote Data Management Distributed Data Management

24 IT for Management Prof. Efraim Turban T4-24 Peer-to-Peer Architecture Network information is stored on a centralized file server and made available to ma clients, the Information stored across peer-to-peer networks is uniquely decentralized. Popular peer-to-peer network operating systems include Microsoft’s Windows 95 and 98, Windows NT, Artisoft’s LANtastic, and Netware Lite.

25 IT for Management Prof. Efraim Turban T4-25 Open Systems and Enterprise Networking Connectivity –the ability of the various computer resources to communicate with each other through network devices without human intervention Portability –the ability to move applications, data, and even people form one system to another with minimal adjustments Interoperability –the ability of systems to work together by sharing applications, data, nd computer resources. Scalability –the ability to run applications unchanged on any open system where the hardware can range form a laptop PC to a supper computer

26 IT for Management Prof. Efraim Turban T4-26 Open Systems and Enterprise Networking Embedded LANs –open systems and connectivity have enabled networks to completely span organization –Most firms have multiple LANs and may have multiple WANs, which are interconnected to form an enterprisewide network

27 IT for Management Prof. Efraim Turban T4-27 Internet Basic Characteristics and Capabilities –Accessing the Internet access an internet-connected file server on your organization’s LAN log into the Internet from your home wireless connections –TV as a channel to the Internet a special connection device, and a telephone connection

28 IT for Management Prof. Efraim Turban T4-28 Internet The TCP/IP Protocol –procedures and rules for transferring data across the internet Internet Resources –access libraries and conduct research –access to large databases –access to online magazines Wide Area Information Servers (WAIS) –an Internet directory designed to help end users find and retrieve information over the networks by providing efficient search methods

29 IT for Management Prof. Efraim Turban T4-29 Internet The World Wide Web –a vast connection of interconnected pages of information that are stored on computers around the world that are connected to the internet Bowser –a set of standards for storing, retrieving,and manipulating information Hyperlinks –links to internal or external documents Web Site : a computer network Web Page : a document

30 IT for Management Prof. Efraim Turban T4-30 Internet Creating Web Documents –HyperText Markup Language (HTML) –Java Search Engines –enable you to locate information by using key words in the same way that you would search online library resources Internet Addresses –uniform resource locator (URL) –hypertext transfer protocol (HTP)

31 IT for Management Prof. Efraim Turban T4-31 Internet Gopher –a “burrowing tool” that provides access to a wide range of textual information available on the Internet Downloading Software and Files –cheapware, freeware, and shareware –file transfer protocol (FTP) Electronic Mall (e-mall) –allows multiple-access communication delivered exclusively on a computer network

32 IT for Management Prof. Efraim Turban T4-32 Internet Chat Programs –allow you to send messages to people at the same time Newsgroup –organized in a directory and are divided into categories and subcategories Mailing Lists –subscribe : add name and address –unsubscribe : remove the name and address Electronic Bulletin Boards –allow people leave messages for other people and receive massive amounts of information Portals –a Web site designed to offer Internet services

33 Copyright  2001 John Wiley & Sons, Incorporated. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without the express written permission of the copyright owner in unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Son, Inc. Adopters of the textbook are granted permission to make back-up copies for his/her own use only, to make copies for distribution to student of the course the textbook is used in, and to modify this material to best suit their instructional needs. Under no circumstances can copies be made for resale. The publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein. IT for Management Prof. Efraim Turban 6-33


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