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
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–
–
–
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
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•
•
•
•
•
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 UnionTelecommunication Standardization Sector (ITUT)
– 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
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•
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•
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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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