Facility Wiring TDR

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Facility WiringTDR
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Overview

• Guided - wire
• Unguided - wireless
• Characteristics and quality determined by medium
  and signal
• For guided, the medium is more important
• For unguided, the bandwidth produced by the
  antenna is more important
• Key concerns are data rate and distance

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Design Factors

• Bandwidth
• Higher bandwidth gives higher data rate
• Transmission impairments
• Attenuation
• Interference
• Number of receivers
• In guided media
• More receivers (multi-point) introduce more
  attenuation

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Wiring Closet

• Orderly Cable Layout
• Can include all of the following
• Network equipment
• Fiber optic cables, CAT5
• WAN connections
• LAN distribution
• Electrical
• Video / Cable TV
• Telephone
• Alarm systems intrusion, fire, door

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Wiring Closet

• Orderly Cable Layout
• Needs
• HELP!!!!!

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Wiring Closet

• Orderly Cable Layout

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Wiring Closet
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Wiring Closet
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Wiring Closet
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Wiring Closet
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Patch Panels
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RJ-45 Fabrication
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RJ-45 Fabrication
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Time Domain Reflectometer
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Time Domain Reflectometer

• Works by transmitting a pulse of energy into a
  cable
• Observing that energy as it is reflected by the
  system

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Time Domain Reflectometer

• Blind Spot
• Width of pulse
• Speed reduced based on media type

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Time Domain Reflectometer

• Distance vs. VOP
• Velocity of Propagation speed of light
• Speed of light in vacuum 299,792,458 m/s ( C )
• VOP varies in different media presented as a
• Distance pulse travels (D) C x Time (T)
• DCT T D/C
• Measured time from transmission of pulse to
  receipt of reflected pulse calculate distance
• Round trip delay 0.000667128 sec 299,792,458
  m/s 200,000
• Length 200,000 / 2 100,000 meters
• Speed reduced based on media type

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Time Domain Reflectometer

• Distance - Time

T D/C
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Time Domain Reflectometer

• VOP for various media
• Important for VOP to be accurate
• Measured or Obtained from MFR

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Time Domain Reflectometer

• Examples of VOP

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Time Domain Reflectometer
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           A reflection with the same polarity
indicates a fault with OPEN (high impedance)
tendencies. The reflection shown at the second
cursor is a COMPLETE OPEN.
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           A reflection with the opposite
polarity indicates a fault with short (low
impedance) tendencies. The reflection shown at
the second cursor is a DEAD SHORT.
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           The middle reflection at the second
cursor is a PARTIAL OPEN followed by a COMPLETE
OPEN (end of the cable). The more severe the
fault, the larger the reflection will be.
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           The middle reflection at the second
cursor is a PARTIAL SHORT followed by a COMPLETE
OPEN (end of the cable). The more severe the
fault, the larger the reflection will be.
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           Two sections of coaxial cable with a
barrel connector shown at the second cursor. The
amount of reflection caused by the connector is
directly proportional to the quality of the
connector and connection.
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           Coaxial taps (both indoor and
outdoor) will cause reflections along the
waveform. The quality and value of each tap
determines the amount of reflection.
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           A splitter or directional coupler can
be identified although accurate measurements are
difficult due to multiple reflections. The second
cursor identifies the splitter. The two
reflections following are the ends of each of the
two segments.
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           A water soaked cable will display a
waveform with a downward slope indicating the
beginning of the water and an upward rise at the
end of the water . Generally, the area in between
the two reflections will appear "noisy".
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           Pulse Waveform 2 - Medium Pulse Width
The width of the output pulse is also referred
to as the blind spot or dead zone. It is more
difficult to "see" a fault when it is contained
within the blind spot.
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Time Domain Reflectometer

• http//www.tscm.com/riserbond.html
• http//www.nuvotechnologies.com/pdf/crimping.pdf
• http//www.pcnineoneone.com/howto/cat5diy1.html
• http//www.commserv.ucsb.edu/infrastructure/standa
  rds/history/EIA-TIA_568.aspFour-pair