Information Technology in Business: Telecommunications, Networks and Internet Basics

MIS 2212 Learning Objectives When you finish this chapter, you will: –Recognize why successful managers must be familiar with telecommunications concepts and terminology. –Know the principles of communication within a computer system and among computers. –Be able to identify the major media and devices that are used in telecommunications.

MIS 2213 Learning Objectives –Be able to list and explain the functions of different network layouts and the concept of protocols. –Understand how telecommunications can improve operations in organizations. –Know the latest developments in telecommunications media and transmission speeds. –Understand the historical development of the Internet –Understand the main structural components of the Internet –Understand how HTML, HTTP, browsers and servers work together to form the WWW

MIS 2214 Telecommunications in Business Telecommunications –Any form of long distance communication, including telephone, television and radio Telecommunications has improved business in three main ways: –Better communication –Higher efficiency –Better distribution of data

MIS 2215 What is Data Communications? Data Communications –Any transfer of data within a computer, between a computer and another device, or between two computers Integration –Business are increasingly integrated in their use of computers, telephony, video and data networks

MIS 2216 What is a Telecommunications System? Compatible hardware and software used to communicate information from one place to another –Will include voice, text, graphics, documents and video

MIS 2217 A Generalized Telecommunications System Hardware (Host computer, front end communication processor, modem, multiplexor) Communications media (Cable or wireless) Communications software Data communications providers Communications protocols Communications applications (EDI, videoconferencing, EFT, etc.)

MIS 2218 Electronic Signals Analog –Information imbedded in the changing characteristics of the wave Amplitude or frequency based Digital –Information imbedded as 1 or 0, on or off

MIS 2219 Modulation Figure 6.8 Signal modulation

MIS Modulation Amplitude Modulation (AM) Frequency Modulation (FM) Phase Modulation

MIS Multiplexing Figure 6.9 Multiplexing

MIS Communications Devices Modems –Devices that modulate and demodulate signals, converting from analog to digital and digital to analog Multiplexers –Devices that allow several telephones or computers to transmit data through a single line Frequency-division multiplexing Time-division multiplexing Front End Processors

MIS Channels and Media Communication Channel –Physical medium through which data can be communicated. Channel Capacity –Narrow band –Broadband

MIS Channels and Media Media –A medium is any means by which data can be transmitted. Transmission speed –A medium’s capacity is determined by the range of bits per second at which it can operate. Baud Repeater

MIS Channels and Media Twisted Pair –Telephone line made of a pair of copper wires twisted to reduce electromagnetic interference (EMI) Coaxial Cable –Commonly used for cable television transmission More expensive than twisted pair Greater transmission rate than twisted pair Much less susceptible to EMI

MIS Channels and Media Microwaves –High-frequency, short radio-frequency (RF) waves Terrestrial microwave Satellite microwave Optical Fiber –Fiber-optic technology uses light instead of electricity to transmit data. Cellular and Wireless –Radio frequency technologies –Fixed or mobile

MIS Channels and Media Figure 6.5 Transmission speed measurement unit

MIS Channels and Media Figure 6.6 Telecommunications transmission speeds of different media

MIS Channels and Media Figure 6.7 Characteristics of channel media

MIS A Variety of Services Figure 6.15 Services offered by telecommunications firms

MIS What is Data Communications? Figure 6.1 Parallel and serial transmission

MIS Communication Direction Three Modes of Communication Between Devices –Simplex One direction only –Half-Duplex Both directions, but only one at a time –Full-Duplex Simultaneous in both directions

MIS Communication Direction Figure 6.2 Simplex, half-duplex, and full-duplex communication

MIS Communication Direction Asynchronous Communication –In asynchronous transmission, the devices are not synchronized by any timing aids. –Advantage Does not need sophisticated and expensive timing hardware –Disadvantage Overhead, time spent transmitting bits that are not a part of the primary data

MIS Communication Modes Figure 6.3 The character D transmitted in asynchronous mode

MIS Communication Modes Synchronous Communication –In synchronous communication, data are transmitted using timing devices. –Messages are transmitted in packets. –Advantage of synchronous communication Overhead in synchronous communication is significantly smaller than in asynchronous communication.

MIS Communication Modes Figure 6.4 Synchronous transmission

MIS Protocols Definition –Rules and procedures governing transmission across a network Line access Collision avoidance TCP/IP –Standard protocol of the Internet and intranets –Transmission Control Protocol/Internet Protocol –Designed for sending large files across unreliable networks –Utilizes packets of information

MIS OSI Standard Seven Layer Model –Governs peer-to-peer communication between software at each layer –From physical layer (how bits are transmitted over a channel) –To application layer (file transfer, security, etc)

MIS Open Systems Interconnect Model Figure 6.14 The seven layers of the OSI model

MIS Networks LANs (Local Area Networks) –Networks within a building, or within a group of adjacent buildings WANs (Wide Area Networks) –Networks across significant distances, either within a single organization or spanning multiple organizations Value-added networks (VANs) Wireless communication

MIS Network Topology Figure 6.12 Network topologies

MIS Networks Devices Bridge –Connects two networks at the data link layer Router –Connects two networks at network layer –Provides intelligent routing, some network management functions and security Gateways –Connect networks using different protocols Switches –Incorporate features of bridges and gateways

MIS Other Standards (or lack thereof) Operating Systems –No standard exists Graphical User Interface –X Windows Software Applications –No standard for programming language, DBMS, etc.

MIS Client/Server Computing Enabled by proliferation of powerful desktop computers and decentralized servers Principle –Processing functions divided between to separate, distinct computers –One requests services of a server (the client) –One delivers a service upon request (the server)

MIS Example of Client/Server Computing – client (Outlook) sends request to POP server for messages –POP Server receives and validates request to download –Client processes data received (formats, displays, stores messages)

MIS Example of Client/Server Computing Database Transaction –Client program running on PC sends query to DBMS running on central server –DBMS on server parses and executes the query –DBMS assembles resulting data (or status result) and sends it to client –Client receives data and processes it (displays it, sends message to user, etc)

MIS Benefits of Client/Server Computing Potential to reduce cost –By offloading computing cycles to cheaper and underutilized desktop PC Improved performance –Has enabled high-performing graphical user interfaces