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Chapter 9. Communications and Networks. Competencies (Page 1 of 2). Discuss connectivity, the wireless revolution, and communication systems Describe physical and wireless communications channels Discuss connection devices, including modems, T1, DSL, cable modem, and satellite connections - PowerPoint PPT Presentation
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Communications and NetworksChapter 9
CE06_PP09-2
Competencies (Page 1 of 2)
Discuss connectivity, the wireless revolution, and communication systemsDescribe physical and wireless communications channelsDiscuss connection devices, including modems, T1, DSL, cable modem, and satellite connectionsDescribe data transmission factors, including bandwidths and protocolsDiscuss network and key network terminology
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Competencies (Page 2 of 2)
Describe different types of networks, including local area, metropolitan area, and wide area networks
Describe network architectures, including configurations and strategies
Describe organizational uses of Internet technologies, including intranets, extranets, and firewalls
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Communications
The process of sharing data, programs, and information between two or more computers
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Communication SystemsFour basic elements
Sending and receiving devices
Communication channel
Connection devices
Data transmission specifications
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Communication Channels
Channels carry data from one computer to
another
Two categories of communication channels
Physical connection
Wireless connection
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Physical Connections
Telephone lines
Coaxial cable
Fiber-optic cable
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Return
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Wireless Connections -Infrared, Broadcast Radio, Microwave
Infrared
Broadcast radioWi-FI (wireless fidelity)/802.11
MicrowaveStations
Bluetooth
SatelliteGPS
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Microwave dish
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Connection Device Signals
Types of signalsAnalog
Digital
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Connection Device Types
Types of modemsExternal
Internal
PC Card
Wireless
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Connection ServicesDial-Up services
Leased lines – T1, T2, T3 and T4
Digital subscriber line (DSL)Uses existing phone lines
One type widely used is ADSL
Cable modemsUses existing TV cable
Provides speeds as fast as DSL at a lower cost
Satellite/air connection services Seven times faster than dial-up
Slower than DSL & cable modem
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Typical User Connection Costs & Speeds
TypeType FeeFee SpeedSpeed Seconds to Get Seconds to Get ImagesImages
Dial-up $16 56 kbps 45.0
DSL 50 1.5 mbps 1.7
Cable Modem 40 1.5 mbps 1.7
Satellite 60 900 kbps 2.8
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Bandwidth
Measurement of the capacity of the channel
Categories Low bandwidths or Voiceband
Medium band
BroadbandUsed for high capacity transmission
Used by DSL, cable, and satellite
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Protocols
Set of communication rules
Standard for Internet: TCP/IP (Transmission control protocol/Internet protocol)
Identifies devices
Reformats information
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Networks
A computer network is a communication system
Connects two or more computers
Allows information exchange
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Network Types
A local area network (LAN): computers are physically close to each other, usually in the same building
Metropolitan area network (MAN) links two or more LANs within a city
A wide area network (WAN) extends over a long distance Each network site is a node on the network Data transmitted over common pathways called a
backbone
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Internets and ExtranetsIntranets
Private network within an organization
Provides information to employees
ExtranetsPrivate network that connects organizations
Used to allow suppliers and others access
FirewallsSecurity system
Protects against external threats
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