Facility WiringTDR

OverviewGuided - wireUnguided - wirelessCharacteristics and quality determined by

medium and signalFor guided, the medium is more importantFor unguided, the bandwidth produced by

the antenna is more importantKey concerns are data rate and distance

Design FactorsBandwidth

Higher bandwidth gives higher data rate

Transmission impairments Attenuation

InterferenceNumber of receivers

In guided media More receivers (multi-point) introduce more

attenuation

Wiring ClosetOrderly Cable LayoutCan include all of the following:

Network equipmentFiber optic cables, CAT5WAN connectionsLAN distribution

Electrical Video / Cable TV Telephone Alarm systems: intrusion, fire, door

Wiring ClosetOrderly Cable Layout

Needs HELP!!!!!

Wiring ClosetOrderly Cable Layout

Wiring Closet

Wiring Closet

Wiring Closet

Wiring Closet

Patch Panels

RJ-45 Fabrication

RJ-45 Fabrication

Time Domain Reflectometer

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

                                                                                                   

              

Time Domain Reflectometer Blind Spot

Width of pulse Speed reduced based on media type

Speed of Light = 299,792,458Pulse Width (time) Pulse Width (meters)

1u second 0.000001 299.792458100 nsec 0.0000001 29.979245810 nsec 0.00000001 2.997924581 nsec 0.000000001 0.299792458

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)

D=C*T ; 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

Time Domain Reflectometer Distance - Time

Distance (meters) Time (seconds) one way1000 3.33564E-06

10000 3.33564E-05100000 0.000333564

1000000 0.00333564110000000 0.03335641

100000000 0.3335640951000000000 3.335640952

10000000000 33.35640952

T = D/C

Time Domain Reflectometer VOP for various media Important for VOP to be accurate Measured or Obtained from MFR

CABLE TYPE TYPE VOPTELEPHONE

19 AWG Gel-Filled 6822 AWG Gel-Filled 6624 AWG Gel-Filled 6226 AWG Gel-Filled 6019 AWG AIR 7222 AWG AIR 6724 AWG AIR 6626 AWG AIR 64

Polyethylene 66Polypropylene 66Teflon 69PIC 67Pulp 72

CATV

Belden Foam 78S-82Solid 66

Comm/Scope (F) 82PARA I 82PARA III 87QR 88

Time Domain Reflectometer

Examples of VOP

Time Domain Reflectometer

                                                      

     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.

                                                      

     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.

                                                      

     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.

                                                      

     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.

                                                      

     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.

                                                      

     Coaxial taps (both indoor and outdoor) will cause reflections along the waveform. The quality and value of each tap determines the amount of reflection.

                                                      

     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.

                                                      

     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".

                                                      

     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.

Time Domain Reflectometer

http://www.tscm.com/riserbond.htmlhttp://www.nuvotechnologies.com/pdf/cri

mping.pdf

http://www.pcnineoneone.com/howto/cat5diy1.html

http://www.commserv.ucsb.edu/infrastructure/standards/history/EIA-TIA_568.asp#Four-pair