Business Data Communications, Fourth Edition

Chapter 1: Introduction to Communications

Learning Objectives

• Define data communications• Describe the difference between data

communications and telecommunications• Define local area networks, wide area

networks, metropolitan area networks, wireless networks, and personal area networks

• Understand the components of a communications system

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Learning Objectives

• Describe the role of, and list, regulatory agencies in data communications

• List the standards-setting organizations involved in the communications industry

• Explain how the government uses communications networks

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Introduction

• Communications began from primitive methods

• More efficient communications were needed with the advance of the industrial age

• The telegraph began the age of electronic communications

• Voice, video, and data transmitted in modern communications systems

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What is Data Communications?

• Transmission of data over a network• Subset of telecommunications• Networks

– Telephone system– May connect computers and related devices– PC prices have dropped – Data communications network

• Computers and related devices• Devices and lines used to connect the devices

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What is Data Communications?

• Networks– Types of networks

• Wide area network (WAN)• Local area network (LAN)• Metropolitan area network (MAN)• Internet• Wireless networks• Personal Area Network (PAN)

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Basic Components of a Communications System

– Three physical components• Source (or sender)• Medium• Receiver

– One Software component• Protocol

– Circuit– Example – Drive-up bank window

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The Telephone System

• Telegraph – 1840

• Telephone – 1876

• AT&T was a monopoly– Positive aspects of standardization

• Divestiture in 1984

• Data communications and the telephone system

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The Telephone System

• Common Carriers– Profit-oriented companies– Over 1200 in the United States– Cellular service providers– Local and long distance service

• IntraLATA Calls– Local Access Transport Areas (LATAs)– Local and “local long distance”

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The Telephone System

• InterLATA Calls– Long distance calls– May or may not use a carrier different from

the one offering local telephone service– Divestiture has allowed all companies to

compete in both local and long distance markets

– Slamming – unauthorized switch to a different phone company

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Governmental and Regulatory Agencies

• Federal Communications Commission (FCC)– Created in 1934– Prior to that time, the Interstate Commerce

Commission controlled communications– Regulates interstate and international

telecommunications– Tariff schedules

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Governmental and Regulatory Agencies

• Public Utility Commissions– Regulate intrastate communications– Regulate common carriers within a state– Rates charged can differ by state– Negotiates when conflicts arise, if the problem

is completely within a single state

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Governmental and Regulatory Agencies

• National Telecommunications and Information Administration (NTIA)– Branch of the U.S. Department of Commerce– Catalyst for innovation in communications

industry– Helps create jobs in that sector– Establishes grants to create a

communications infrastructure for all citizens

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Standards Organizations

• American National Standards Institute (ANSI) – Creates voluntary national standards– Has over 1,000 members– Works to create consensus on standards

among all the groups– Publishes standards created by other

organizations– Creating a standard for FDDI

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Standards Organizations

• International Organization for Standardization (ISO)– Non-electronic telecommunication standards– Created the Open Systems Interconnection

(OSI) 7-layer model

• Corporation for Open Systems– Promotes the use of equipment that meets

ISO standards

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Standards Organizations

• International Telecommunication Union (ITU)– Equipment standards in other countries– Provides technical assistance in setting up

communications systems in third world countries• International Telecommunication Union-

Telecommunication Standardization Sector (ITU-T)– Fosters cooperative standards for

telecommunications equipment and systems– Took over functions of the CCITT

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Standards Organizations

• Institute of Electrical and Electronics Engineers (IEEE)– An ANSI member organization– Standards developed for the lowest two levels

of the OSI model– Developed standards for local area networks

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Standards Organizations

• Electronics Industries Association (EIA)– Sets electrical standards– Members are manufacturers of electrical equipment– Developed standards for the lowest level of the OSI

model• Telecommunications Industry Assn. (TIA)

– Members are companies that provide communications and other IT products and services

– Acts as a voice on public policy and international matters that affect its members

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Standards Organizations

• Committee T1– Provides standards for interfaces– Accredited by ANSI– Addresses issues related to interconnection of

customers to public communications carriers

• Personal Communications Industry Association (PCIA)– Trade association for the personal communications

services industry– Regulations and standards related to wireless

communications

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Standards Organizations

• Cellular Telecommunications Industry Association (CTIA)– Conducts surveys on use of cellular technology

• Communications Satellite Corporation (COMSAT)– Coordinates use of satellites among countries, and

represents the USA

• International Telecommunications Satellite Organization (INTELSAT)– Coordinates use of satellites internationally

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Applications of Data Communications

• Computer system processing– Early systems

• Batch• No networks

– Modern systems • On-line• Networks

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Applications of Data Communications

• Government Applications– Original use – Census data collection in 1950– Internal Revenue Service (IRS)– National Aeronautical and Space

Administration (NASA)– Military uses

• The Internet– E-Commerce

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Chapter Summary

• Rapid increase in communications

• Data transmission

• Three components of communications

• Common carriers

• FCC and PUCs

• Regulatory agencies

• Common uses for communications networks

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Chapter 1 Complete