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1 LIDO Telecommunications Essentials® Part 1 Communications Fundamentals Traditional Transmission Media

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Page 1: 1 LIDO Telecommunications Essentials® Part 1 Communications Fundamentals Traditional Transmission Media

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LIDO Telecommunications Essentials®Part 1

Communications Fundamentals

Traditional Transmission Media

Page 2: 1 LIDO Telecommunications Essentials® Part 1 Communications Fundamentals Traditional Transmission Media

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Contents

• Transmission media, applications• Microwave, WWANS, WMANs, WLANS, WPANS,

Satellites• Fiber optic

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Transmission Media CategoriesTransmission Media Categories

• Copper Cable

• Wireless

• Fiber Optic Cable

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Traditional Transmission Media Characteristics

Media Type Bandwidth Performance Repeater

Spacing

Twisted-pair 1 MHz Poor to Fair10-5 – 10-7

short6,000ft/2km-analog1,800ft/600m-digital

Coax cable 1 GHz Good

10-7 – 10-9

short8,000ft/2.5km

Microwave 100 GHz Good

10-7 – 10-9

mediumup to 45miles/72 km

Satellite 100 GHz Good

10-7 – 10-9

long-very longup to 22,300miles/36,000 km for GEO

Fiber 75 THz Great

10-11 – 10-13

longup to 4,000miles/6,000km

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Twisted Pair

•Limited frequency spectrum- 1MHz

•Inverse relationship between distance of loop and the data rate

•Short distances between repeaters

•Susceptible to interference and distortion

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Twisted Pair Categories

• Two varieties of twisted pair– Unshielded Twisted Pair(UTP) or Shielded Twisted Pair

(STP)• Category 1 - no data, telephony only• Category 2 – up to 4 Mbps• Category 3 – up to 10 Mbps• Category 4 – up to 16 Mbps• Category 5 – up to 100 Mbps• Category 5e- up to 1.2 Gbps• Category 6 – up to 3 Gbps• Category 7 – up to 10 Gbps

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Twisted Pair ApplicationsTwisted Pair Applications

• Premises distribution systems wiring (local cabling)

• Private branch exchange wiring• Local area network• Local loop cabling

– analog subscriber lines– digital subscriber lines

• ISDN (Integrated Services Digital Network)• xDSLs (Digital Subscriber Line)

– HDSL, ADSL, SDSL, SHDSL, RADSL, VDSL

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Twisted Pair Digital Subscriber Lines

• N-ISDN– BRI = 2B + D

• 2-64 Kbps B-channels, 1-16 Kbps D-channel– PRI = 23B + D / 30B + D

• 23-64 Kbps B-channels, 1-64 Kbps D-channel• 30-64 Kbps B-channels, 1-64 Kbps D-channel

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Twisted Pair Digital Subscriber Lines• xDSLs

– HDSL• Symmetrical, up to 2 Mbps in each direction

– ADSL, ADSL2, ADSL2+• Asymmetrical, up to 24 Mbps downstream and 1 Mbps upstream

– SDSL• Symmetrical, up to 2 Mbps in each direction

– SHDSL• Symmetrical, up to 5.6 Mbps in each direction

– RADSL• Asymmetrical or symmetrical, up to 7 Mbps downstream, and 1 Mbps upstream

– VDSL• Asymmetrical or symmetrical, up to 100 Mbps in each direction

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Twisted Pair AdvantagesTwisted Pair Advantages

• High availability– over 1 billion main telephone subscriber lines

worldwide

• Low cost of installation on premises

• Low cost for local moves, adds and changes in places

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Twisted Pair DisadvantagesTwisted Pair Disadvantages

• Limited frequency spectrum

• Limited data rates

• High susceptibility to signal interference – electromagnetic interference, radio frequency interference

• High error rate

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Coaxial CableCoaxial Cable

Outer jacket

Braided-coppershielding

Plastic insulation

Copper conductor

•Large frequency spectrum–370, 550, 750, and 1000 MHz systems

•Allows multiple channels to be created on one cable using multiplexing techniques•Better performance than twisted pair•Amplifiers spaced every 8,000 feet / 2.5 km

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Traditional Cable TV Networks

Head EndHead EndPrimary HubPrimary Hub

Amplifier Cascades

Cable TV or Multiple System Operator (MSO)

Pre-recordedContent

International TV

Satellite Feeds

Local TV Broadcasts

Coax Network

Head EndHead EndSecondary HubSecondary Hub

TraditionalCoax Backbone

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HFC Network (Hybrid-Fiber-Coaxial)

Optical NeighborhoodNodes

FiberCoaxial Cable

500-2000Home Area

Fiber Backbone

Fiber Backbone

HeadEnd

HeadEnd

Bus Topology

HeadEnd

HeadEnd

HeadEnd

HeadEnd

MSO Backbone

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Coaxial Cable ApplicationsCoaxial Cable Applications

• Telephone company inter-office trunking

• International submarine cables

• Data processing (terminal-to-host connections)

• Local area networking

• Community antenna TV (CATV)

• Local loop (hybrid fiber coax architectures)

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Coaxial Cable AdvantagesCoaxial Cable Advantages

• Broadband system– multichannel, high bandwidth

• Greater channel capacity• Large bandwidth supports high speed data and

multimedia services• Lower error rates due to less distortion• Greater spacing between amplifiers

– due to cable shielding which reduces noise and crosstalk

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Coaxial Cable DisadvantagesCoaxial Cable Disadvantages

• Generally deployed in bus architecture– shared bandwidth, security risks

• In some countries, majority of cable infrastructure is one way, requiring upgrade to bidirectional systems

• In two way systems, the return path is subject to noise problems

• High installation costs in local environment• High costs for local moves, adds and changes• Susceptible to damage from lightening strikes

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Microwave Network

•Operates in the 1GHz to 100 GHz frequency band•Medium bandwidth•Uncertain performance•Repeater spacing varies with frequency band•Requires line of sight•Impacted by environmental conditions

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Microwave NetworkMicrowave Network

BB

AA

CC Microwave Tower/Dish

Microwave Tower/Dish

Line of Sight Required

Commercial Systems Operate in 1-50 GHz range

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Connecting Multiple PABX’sConnecting Multiple PABX’s

TRANSMITTER

RECEIVER

INTERFACE

TIE TRUNKS

PABX

TRANSMITTER

RECEIVERINTERFACE

TIE TRUNKS

PABX

BUILDING A BUILDING B

BEFORE

AFTER

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By-passing Construction By-passing Construction

TRANSMITTER

RECEIVER

INTERFACE

PABX LINESW. DISTRIBUTION

PPPP

P

P

P PP

P

P

P

PP

TRANSMITTERRECEIVER

INTERFACE REMOTELINE

SWITCH

P

P P

P

P

CABLE

EXPANDED DEPT.

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Local Area Network InterconnectLocal Area Network Interconnect

TRANSMITTER

RECEIVER

INTERFACE

UPTOWNFACILITIES

T

T

T

T

TRANSMITTER

RECEIVER

INTERFACE

DOWNTOWNFACILITIES

T

T

T

T

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Microwave AdvantagesMicrowave Advantages

• Cost savings compared to leased lines

• Portability

• Substantial bandwidth

• Reconfiguration flexibility

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Microwave DisadvantagesMicrowave Disadvantages

• Line-of-sight requirement

• Susceptibility to environmentally caused distortions

• Regulatory licensing requirement

• Potential environmental restrictions

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Broadband Wireless Microwave Applications

• WWANs– 2G – PCS implementations of TDMA, GSM and CDMA– 2.5 – GPRS, HSCSD, EDGE– 3G - W-CDMA, UMTS, cdma2000, TD-SCDMA– 3.5G - HSDPA, HSUPA, HSOPA– 4G - OFDM and MIMO technologies

• WMANs– broadband fixed wireless access (BFWA) systems– IEEE 802.16 WiMax, Wi-Bro– ETSI's BRAN, HiperMAN and HiperACCESS, – Flash-OFDM, iBurst Personal Broadband System– IEEE 802.20 Mobile-Fi, IEEE 802.22 Wi-TV

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Broadband Wireless Microwave Applications

• WLANs– IEEE 802.11 family of protocols– ETSI HiperLAN and HiperLAN2

• WPANs– IEEE 802.15.1– Bluetooth– IEEE 802.15.3 WiMedia– Ultra Wideband (UWB)– IEEE 802.15.4 ZigBee– some applications of RFID

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Satellite Frequency Allocations

Frequency Band• C-band• Ku-band• Ka-band• L-band

Uplink/Downlink• 6 / 4 GHz• 14 / 11 GHz• 30 / 20 GHz• 2 / 1 GHz

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IEEE Radar Frequency Bands

BAND FREQUENCY RANGE

HF 3 MHz – 30 MHz (amateur radio, CB radios)

VHF 30 MHz – 300 MHz (FM Radio, TV)

UHF 300 MHz – 1 GHz (TV, mobile)

L 1 GHz – 2 GHz (mobile, GPS)

S 2 GHz – 4 GHz (mobile, satellite telemetry)

C 4 GHz – 8 GHz (fixed voice, satellite TV)

X 8 GHz – 12 GHz (military)

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IEEE Radar Frequency BandsBAND FREQUENCY RANGE

Ku 12 GHz – 18 GHz (fixed, direct broadcast satellite TV)

K 18 GHz – 27 GHz (fixed)

Ka 27 GHz – 40 GHz (fixed, radar)

Q 30 GHz – 50 GHz (radar)

V 40 GHz – 75 GHz (scientific research)

W 75 GHz – 110 GHz (realtime networks for avionics, military radar)

mm 110 GHz – 300 GHz (telemetry, astronomy)

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Satellite Services

• Fixed Satellite Services (FSS)– conventional fixed services– C-band (6/4 GHz) and Ku-band (14/12 GHz)

• Broadcast Satellite Services (BSS)– TV, Direct Broadcast Satellite (DBS)– Ku-band (18 GHz)

• Mobile Satellite Services (MSS)– mobile services– Ka-band (30/20 GHz), L-band (1/2 GHz)

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Satellite Properties

•Each satellite has a footprint

•Broadcast property enables efficient and cost-effective support of point-to-multipoint applications

•The more locations, the most cost-effective the network

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Objects Orbiting EarthObjects Orbiting Earth

http://cse.ssl.berkeley.edu/lessons/indiv/dataflow/HomePage.html33

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Satellite StructuresSatellite Structures

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VSATs

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Satellite OrbitsSatellite Orbits

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GEO SystemsGEO Systems

• GEO - Geosynchronous Earth Orbiting• Orbit 22,300 miles / 36,000 km• Delay of 0.25 (one-way) to 0.50 second

(round-trip)• GEO orbits provide the largest footprint• Requires the least number of satellites for

global coverage• Requires the most power

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GEO SystemsGEO Systems

• Data rates up to 155 Mbps possible, in Ka-band• High data rates necessitate large antennas,

especially for GEO systems• Parabolic satellite antennas 10 meters in diameter

can now be built, should be possible to extend to 20 or 30 meters

• Key applications include point-to-multipoint connections, one-way broadcast, international TV, and VSAT systems.

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VSAT ApplicationsVSAT Applications

• Data networking– Point-of-sale, credit authorization, inventory

control, remote processing, reservations and transactions

• Business video• Disaster recovery• Vehicle tracking systems• Internet access• Intranets• Direct Broadcast Satellite

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VSAT HubsVSAT Hubs

VSATs VSATsHUB Station

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VSAT for Broadband Internet Access

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VSAT AdvantagesVSAT Advantages

• Access to remote locations• Rapid deployment• Scalable• Platform agnostic• Distance insensitive transmission costs• Further cost reductions via shared-hub

facilities• Flexible network configuration

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VSAT DisadvantagesVSAT Disadvantages

• Transmission quality subject to weather conditions

• Local zoning restrictions

• Potentially high start-up costs for small installations

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MEO Satellites• MEO - Middle Earth Orbiting

• Orbit 6,200- 9,400 miles / 9,920-15,040 km above the equator

• Satellites closer to the earth move across the sky in 1-2 hours

• MEOs require more satellites than GEOs, but less than LEO systems

• The round-trip delay is 0.10 second

• Applications include mobile voice and low-speed data

•The normal data rate ranges from 9.6 Kbps to 38.4 Kbps

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Low-Earth-Orbiting SatellitesLEOs

• Cellular with moving cells

• Potential to be a system of global bypass

• Low orbits reduce transit times, or delays

• Low orbits reduce power consumption

• Offer increased network capacity

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LEO Satellites

• Orbit 400 to 1,000 miles / 640-1600 km• Can be used with smaller terminals,satellite is 40 times nearer to the earth• Requires 20 times more satellites than GEO system and 5 times more than MEO system• User must always be able to see at least one satellite that is well clear of the horizon• Act as switching stations in the sky• Delay of 0.05 second• Low delay will make interactive services possible• Key applications include mobile voice, low-speed data, and high-speed data

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LEO CategoriesLEO Categories

• Little LEO - operate in 800 MHz range– will deliver messaging, paging, and vehicle location

services, supporting 2.4 to 300 Kbps

• Big LEO - operate in 2 GHz range– will provide voice services to areas not served by

terrestrial or cellular infrastructure– low speed data, 2.4-9.6 Kbps

• Broadband LEO - operates in 20-30 GHz– Ranges from 16 Kbps to 155 Mbps– At 155 Mbps, it can support data and multimedia

applications

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Emerging Satellite ApplicationsEmerging Satellite Applications

• Internet backbones• Internet access• Automotive navigation• Location-based services • Digital audio radio (DARS)• Satellite caching• Multimedia• Telemedicine• Distance learning• Remote imaging• Weather information

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Satellite Challenges• Key satellite challenges today are related to power and

offering mobile services– Due to the small antennas on portable transceivers, satellites

must have a lot of power and sensitivity

• Another innovation involves making use of Extremely High Frequencies (EHF)– Ill effects of the small wavelengths at this frequency can be

mitigated by error-correction techniques, applying more power when necessary, or using more ground terminals

• Developments in virtual fiber (VF-1-10Gbps point-to-point 99% up time) technology address additional obstacles posed by the use of millimeter waves.

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High Altitude Long Endurance (HALE), or Tall Towers

SanswireStratellite

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High Altitude Long Endurance (HALE)

High Altitude Long Endurance (HALE)

• Key advantage is moderate launch cost compared to satellites

• Studies indicate such platforms could support phased-array antennas with some 3,500 beams, enabling mobile two-way communications and video distribution in an area 500 km across

• Some may be dirigibles (zeppelins), others will have wings and fly like conventional aircraft

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Satellite CommunicationsAdvantages

Satellite CommunicationsAdvantages

• Access to remote areas

• Coverage of large geographical areas

• Insensitivity to topology

• Distance insensitive costs

• High bandwidth

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Satellite CommunicationsDisadvantages

Satellite CommunicationsDisadvantages

• High initial cost• Propagation delay with GEO systems• Subject to environmental interference• Danger posed by space debris, solar flare activity and meteor

showers• Licensing requirement• Regulatory constraints in some regions

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Fiber Optics – Making the Cables

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Fiber Optics - The Light Sources

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ITU Wavelength Bands

• These bands are expressed in terms of wavelength sizes measured in nanometers (nm), one billionth of a meter.– Unlabeled 820nm to 900nm– O-Band (Original) 1,260nm to 1,310nm– E-Band (Extended) 1,360nm to 1,460nm– S-Band (Short) 1,460nm to 1,530nm– C-Band (Conventional) 1,530nm to 1,565nm– L-Band (Long) 1,565nm to 1,625nm– U-Band (Ultra-long) 1,625nm to 1,675nm

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Optical Transmission Bands

• We currently make use of three parts of the optical spectrum, or transmission windows. These are bands of minimum loss.

• These bands are about 200 nm (nanometers) wide and are centered around the wavelengths of – 850 nm – using multimode step-index fibers– 1310 nm - used by Multimode Graded Index (GI)

fibers– 1550 nm – used by Single Mode fiber

• Each band has about 25 THz of capacity

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Fiber Optic Characteristics

• The bandwidth of fiber is determined by number of wavelengths it can carry, as well as the data rate supported on each wavelength.– Each year, the number of wavelengths carried per fiber

double, and each year the number of bps carried per wavelength double.

• Repeater spacing up to 500 miles/ 800 km. Spacing of up to 4,000 miles/6,400 km has been successfully demonstrated.

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60LIDOOuter jacket

Kevlar reinforcingmaterial

Glass fiberand cladding

Plastic shield

Fiber Optic CablesFiber Optic Cables

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Fiber Optic CablesFiber Optic Cables

Multimode step-indexOperates at 850nmCore diameter 50.5 µm or 62.5 µm

Multimode Graded Index (GI)Operates at 1,310nm

Single-modeCore diameter 8µm to 12µmNDSF operates at 1,310 nmDSF operates at 1,550 nm

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Fiber Considerations

• One of the major obstacles to high speed (40 Gbps and over) optical networks is the problem of pulse dispersion.

• Optical pulses tend to spread out as they travel over the fiber.

• There are two different causes of pulse dispersion: – Chromatic dispersion (CD)– Polarization mode dispersion (PDM)

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Fiber Optic Light SourcesFiber Optic Light Sources

• Light Emitting Diodes (LEDs)

– less costly

– longer life

– more temperature resistant

– couple only some 3% of the light into the fiber, compared to 50% or more for lasers.

– maximum data rate of 500 Mbps currently

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Fiber Optic Light SourcesFiber Optic Light Sources

• Laser Diodes (LDs)

– capable of higher transmission speeds

– purer light source results in less distortion

– commonly utilized for long-haul and high-speed data transmission

– more expensive

– expecting data rates of 1 trillion bits per second shortly

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Fiber Optic TransmissionFiber Optic Transmission

Laser Diode

Pulses of Discrete Light

Strand of Fiber Optic Glass

Avalanche Photo Detector

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Erbium Doped Fiber Amplifiers(EDFA)

Erbium Doped Fiber Amplifiers(EDFA)

• Introduced in 1994, EDFA’s were a key innovation, made up of erbium metal doped with special atoms, incorporated in an optical fiber at periodic intervals (normally every 30-60 miles) to pump the communications signal.

• Before EDFAs, electronic regenerators had to extract signals, retime them, then regenerate them, limiting data rates to 2.5 Gbps.

• The introduction of EDFAs made it possible for fiber-optic systems to operate at 10Gbps

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Erbium Doped Fiber Amplifiers(EDFA)

Erbium Doped Fiber Amplifiers(EDFA)

• The components in an EDFA include an erbium doped fiber, a laser pump diode, couplers, and isolators.

• EDFA’s opened the way for wavelength division multiplexing.

• Undersea cables need to be designed with WDM in mind, until recently most were not, with one of the problems being inappropriate repeater spacing.

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Fiber Optic ApplicationsFiber Optic Applications

• Public and private network backbones– PSTN, Internet, Cable TV, Power Utilities

• Dark Fiber• Distribution network (local loop)

– HFC: Hybrid Fiber Coax– FTTx: Fiber to the “x” (Curb, Premise, Home, etc)– PON: Passive Optical Networking

• LAN backbones– Fiber Distributed Data Interface (FDDI), Gbps Ethernet

• High-resolution image and digital video– telemedicine, distance learning, entertainment

• Home Area Networks (HANs)

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Fiber Optic Advantages

• Extremely high bandwidth• Elastic traffic carrying capacity• Not susceptible to electromagnetic

impairments or interference• Very low bit error rate• Secure detection – early detection of

intrusion possible• Low in weight and mass

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Fiber Optic DisadvantagesFiber Optic Disadvantages

• High installation costs, but dropping

• Special test equipment required

• Vulnerability to physical damage

• Vulnerability to damage caused by wildlife and flora.

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LIDO Telecommunications Essentials® Traditional Transmission Media

LIDO Telecommunications Essentials® Traditional Transmission Media

Lili GoleniewskiThe LIDO Organization, Inc.www. telecomessentials.com

[email protected]

Skypes ID: lili.goleniewski

Telecom Essentials Learning Centerwww.telecomessentials.com

Copyright © 2007- The LIDO Organization, Inc. All Rights Reserved