Fundamentals of Information Systems, Fifth Edition
Chapter 4 Telecommunications, the Internet,
Intranets, and Extranets
An Overview of Telecommunications
• Telecommunications– The electronic transmission of signals for
communications
• Telecommunications medium– Any material substance that carries an electronic
signal to support communications between a sending and receiving device
Fundamentals of Information Systems, Fifth Edition 3
Fundamentals of Information Systems, Fifth Edition 5
Channel Bandwidth
• The rate at which data is exchanged
• Broadband communications– A telecommunications system that can exchange
data very quickly
Fundamentals of Information Systems, Fifth Edition 6
Communications Media
• Guided transmission media types– Many utilities, cities, and organizations are
experimenting with broadband over power lines (BPL)
• Wireless technologies– Broadcast of communications in one of three
frequency ranges: microwave, radio, and infrared– Near Field Communication (NFC)– Bluetooth– Ultra wideband (UWB)– Wi-Fi
Fundamentals of Information Systems, Fifth Edition 8
Telecommunications Hardware
• Devices include: – Modems, multiplexers, PBXs and front-end
processors that enable electronic communications to occur or occur more efficiently
• Switches, bridges, routers and gateways – Devices for sending packets of data through one or
more networks
Fundamentals of Information Systems, Fifth Edition 9
Services
• Digital subscriber line (DSL)– Telecommunications service that delivers high-
speed Internet access to homes and small businesses over the existing phone lines
• Asymmetric DSL (ADSL) line – Does not require an additional phone line and yet
provides “always-on” Internet access
• Voice over Internet Protocol (VoIP)– Enables voice conversations to be converted into
packets of data that can be sent over a data network
Networks and Distributed Processing
• Computer network– Communications media, devices, and software
needed to connect two or more computer systems and/or devices
• Network nodes– Computers and devices on the networks
Fundamentals of Information Systems, Fifth Edition 11
Network Types
• Personal area network (PAN)– Wireless network that connects information
technology devices within a range of 33 feet or so
• Local area network (LAN)– Connects computer systems and devices within a
small area, such as an office
• Metropolitan area network (MAN)– Connects users and their computers in a geographical
area
• Wide area network (WAN)– Connects large geographic regions
Fundamentals of Information Systems, Fifth Edition 12
Fundamentals of Information Systems, Fifth Edition 13
Distributed Processing
• Centralized processing– All processing occurs in a single location or facility
• Decentralized processing– Processing devices are placed at various remote
locations
• Distributed processing– Computers are placed at remote locations but
connected to each other via a network
Fundamentals of Information Systems, Fifth Edition 14
Client/Server Systems
• Multiple computer platforms are dedicated to special functions, such as:– Database management, printing, communications,
and program execution
Fundamentals of Information Systems, Fifth Edition 15
Communications Protocols
• Set of rules that govern the exchange of information over a communications channel
• Protocols – Govern several levels of a telecommunications
network
Fundamentals of Information Systems, Fifth Edition 16
Communications Software
• Network operating system (NOS)– Systems software that controls the computer
systems and devices on a network and allows them to communicate with each other
• Network management software– Simplifies the process of updating files and programs
on computers on the network