chapter 6. module 6atelecommunications module 6bnetworks 6
TRANSCRIPT
Chapter
6
Chapter
Module 6A Telecommunications
Module 6B Networks
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6
TelecommunicationsTelecommunications
Understanding the Telephone System Modems: From Digital to Analog & Back
Digital Telephony: Living with Twisted Pair
Alternatives to Digital Telephony Convergence: Is It a Phone or a Computer?
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Understanding the Understanding the Telephone SystemTelephone System
Public switched telephone network (PSTN)
Telecommunications
Learn more about the PSTN and fast-breaking new telecommunications technologies? PhoneZone.com’s tutorials.
analog system based on standards that date back more than a century
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Understanding the Understanding the Telephone SystemTelephone System
Telecommunications
Fiber Optics Online is a trade journal specializing in fiber optics industry; this is a great site to learn about new technologies.
Quality of Service (QoS) Local Exchange Carriers (LECs)
local access & transport area (LATA)twisted pairlocal loop
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Long-Distance Long-Distance Transmission MediaTransmission Media
If you place a call outside the local transport area, an interchange carrier (IXC)—a long-distance telephone company—comes into play
Telecommunications
Transmission facilitiescopper wire fiber-optic cablesmicrowavessatellites
Fiber optic cables consist of thin strands of glass that transmit data by means of pulses of light.
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Standards and RegulationsStandards and Regulations
StandardsInternational Telecommunications Union (ITU)
Universal service Common carrier immunity Deregulation
Regional Bell Operating Companies (RBOCs)
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Telecommunications
The home page of Pacific Bell, a RBOC, is packed with information and tutorials about cutting-edge
telecommunications services.
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More Ways to Access More Ways to Access the Systemthe System
Telecommunications
Private Branch Exchange (PBX)
Cellular telephones Leased lines
Cellular telephones enable subscribers to place calls via a wireless
communications system.
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The PSTN in PerspectiveThe PSTN in PerspectiveTelecommunications
As a caller moves from one area to another, a new cell site steps in to keep the signal strong. The sites are connected to a Mobile Telephone Switching Office (MTSO), which is connected to the standard PSTN telephone system.
Sender of callreceiver of call
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Telecommunications
A modem transforms the computer's digital signals into analog tones that
can be conveyed through the telephone system.
How modems workmodulationdemodulationinternal modemexternal modem
sender
receiverTelephone lines use analog transmission
Modems: Modems: From Digital to From Digital to Analog & BackAnalog & Back
Modem 1
Modem 2
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Modems: Modems: From Digital to From Digital to Analog & BackAnalog & Back
Telecommunications
Asynchronous Communicationasynchronous: used by modemssynchronous
Modulation Protocolsdata transfer ratebits per second (bps)V.90 maximum rate of 56 KbpsV.34 maximum rate of 28800 bpsfall back
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FaxFaxTelecommunications
Facsimile transmission enables you to send an image of a document over the telephone lines
to anyone who has a fax machine. If your computer has a fax modem, you can send and
receive faxes from your computer.
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Digital Telephony: Digital Telephony: Living Living with Twisted Pairwith Twisted Pair
Telecommunications
Bandwidthmeasured in Kbps, Mbps, or Gbps
Last mile technologiesIntegrated Services Digital Network (ISDN)Digital Subscriber Line (DSL)Synchronous Optical Network (SONET)
BellSouth is one of the first RBOCs to offer ADSL service. Follow the links to FastAccess to learn more.
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Alternatives to Digital Alternatives to Digital TelephonyTelephony
Telecommunications
In contrast to twisted pair, it’s easy to achieve very high bandwidth data communication with coaxial cable.
Direct Broadcast Satellite (DBS)
Cable Modemscoaxial cable
Electrical Power Systems
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Convergence: Convergence: Is It a Phone Is It a Phone or a Computeror a Computer
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Telecommunications
Digitization enables convergence, a process of technological “morphing” in which previously distinct devices lose their sharply-defined boundaries, and blend together.
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Convergence: Convergence: Is It a Phone Is It a Phone or a Computer?or a Computer?
The everything PC TV Internet set-tops Personal Communication Service (PCS) Internet telephony Internet faxing
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Telecommunications
WebTV allows you to access the Internet using your television set as a display. Visit their web site for more information.
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NetworksNetworks
Introducing Computer Networks Network Fundamentals Local Area Networks (LANs) Wide Area Networks (WANs)
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Introducing Computer Introducing Computer Networks: Networks: Synergy at WorkSynergy at Work
Networks
What is a computer network? Types of computer networks: LANs & WANs
local area networkmetropolitan area networkwide area network
Networking synergies in a nutshellreducing hardware costsenabling shared applicationsbuilding massive information resourcesconnecting people
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Introducing Computer Introducing Computer Networks: Networks: Synergy at WorkSynergy at Work
Networks
Computer networks enable users to share software and to create common pools of data.
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Network FundamentalsNetwork Fundamentals
Physical media Switching & routing techniquescircuit switchingpacket switchingwhich is best
Networks
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Network FundamentalsNetwork FundamentalsNetworks
A message starts at the "top" of a stack of layers and moves down through the various layers (protocol stack) until it reaches
the "bottom" or physical media.
protocol
layers
stack
Protocolsproprietary
protocolsopen protocolsprotocol suite
Network layersthe protocol stack
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Local Area Networks Local Area Networks (LANs)(LANs): : Limited Reach, Fast Limited Reach, Fast
ConnectionsConnections
Networks
LANs transform an organization's hardware into what seems to users like one gigantic computer system.
Computer 1Sales & marketing
Keyboard & monitor for server
Computer 3Personnel
Computer 4Server - Daily sales
Laser printer
Computer 2Accounting
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Local Area Networks Local Area Networks (LANs)(LANs): : Limited Reach, Fast Limited Reach, Fast
ConnectionsConnections
Networks
Networking hardware: Network Interface Cards (NICs)workstationnode
Networking softwarepeer-to-peer networksclient/server networks
Clients
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Local Area Networks Local Area Networks (LANs)(LANs): : Limited Reach, Fast Limited Reach, Fast
ConnectionsConnections
Networks
Mediatwisted paircoaxial cablefiber-optic cableinfraredradio
LAN topologiesbus (daisy chain)starring
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Local Area Networks Local Area Networks (LANs)(LANs): : Limited Reach, Fast Limited Reach, Fast
ConnectionsConnections
Networks
Most networks use a bus, star, or ring topology.
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LAN TechnologiesLAN TechnologiesNetworks
Like to learn more about the Ethernet? Check out Charles Spurgeon’s Ethernet Web Site which covers all the Ethernet
technologies used today and includes a practical guide for do-it-yourselfers.
By far the most popular LAN standard is
Ethernet
By far the most popular LAN standard is
Ethernet
Like to know the latest news about LANs? Check out LAN Times, the premiere LAN trade journal
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LAN ProtocalsLAN ProtocalsNetworks
AppleTalk IPX/SPX NetBEUI TCP/IP
Like AppleTalk, TCP/IP can be used with a variety of lower-level protocols, such as Ethernet. A LAN that uses TCP/IP is called an intranet, a term that suggests that it’s an Internet designed for internal use within an organization.
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Wide Area Networks Wide Area Networks (WANs)(WANs): : Long-Haul CarriersLong-Haul Carriers
Networks
How WANs workPoint of Presence (POP)backbones
WANs are like long-distance telephone systems
The Internet is a WAN of massive proportions. Backbone provider UUNET offers local access from
more than 1,000 locations worldwide.
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Wide Area Networks Wide Area Networks (WANs)(WANs): : Long-Haul CarriersLong-Haul Carriers
Networks
How WANs are organizedpublic data network (PDN)virtual private network (VPN)
WAN protocalsoldest is X.25
WAN ApplicationsLAN-LAN connectionstransaction acquisitionelectronic data interchange (EDI)
To explore cutting-edge WAN technologies such as SDMS and ATM, a good place to start is Pacific Bell’s FasTrak
Data and Video Services page