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12 Cards in this Set
- Front
- Back
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Full-Duplex (2-way)
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simultaneous; transmission with two strands in a fiber cord; each strand carries a signal in one direction
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LAN fiber vs WAN fiber: Wavelengths
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LAN fibers use 850 nm lasers & WAN fibers need 1310 or 1550 nm lasers for longer wavelengths
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multimode fiber
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LANs use ________ has a thick core so light rays can enter over a wide range of angles (modes) - 50 or 62.5 microns
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modal dispersion
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limiting factor for distance in multimode fiber; some light nodes from successive light pulses overlap; caused by too great of a cord length
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absorptive attenuation
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WANs use carrier single-mode fiber and only a single mode can travel through fiber; distance limitation is ________ with light being absorbed by glass molecules
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PSTN (Public Switched Telephone Network)
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worldwide telephone network
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Residential Local Loop
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access link between customer premises and the nearest telephone company switch; uses 1-Pair Voice-Grade
UTP and optical fiber |
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digital subscriber line (DSL)
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data transmitted over 1-pair voice-grade UTP; sends data over voice-grade lines
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Fiber to the Home
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- Fiber is run throughout a neighborhood
- Installed all at once to reduce cost - Only drop lines have to be added to individual homes - Can produce breakthroughs in downstream and upstream speeds to homes - Multiple simultaneous HDTV signals to a home - In practice, the improvement may not be dramatic |
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Cable Modem
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- Provided by cable television companies; the drop line to homes from the main cable uses coaxial cable.
- In “coax,” one wire is in the center and the other conductor is a ring around it, on the same axis. - Data transmission requires two-way amplifiers and a cable modem. |
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Cable modem service
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_____________ tends to be somewhat faster.
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ADSL service
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___________ tends to be somewhat less expensive.
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