Pulling new cable over existing cables may result in damaging the cable that was pulled earlier.. 974 Appendix A: Structured Cablingtermination tool is used to affix a connector to a prep
Trang 1You can find the answers to these questions at the conclusion of Appendix C, “Check
Your Understanding Answer Key.”
Recommendations for network equipment
Look at page 1 of FloorPlan1-Desk-Assignments-building floor1 (ground floor)
Work through the following questions:
What is the purpose of this floor?
What door will workers move freight through?
What doors will visitors come in?
Where are visitors most likely to go after they sign in?
Where would you consider using wireless technology?
Trang 2970 Appendix A: Structured Cabling
If your department someday is tasked with wiring IP security cameras, what areas would you want to keep under surveillance?
From where does the telephone company serve this building?
What kind of lock should it have?
Would the POP be a good place for the servers?
If it is determined that the server room must exist separate from the POP, what consid-erations should guide its location?
Could you install the risers in the POP?
Trang 3Where might you install the risers?
The horizontal cabling always should go parallel to walls Getting to Room 1.2 while
staying parallel to walls makes a cable run of how many meters? Is this useable?
Floor 2
Floor 2 is dense with offices It also contains the bottom floor of an auditorium Not
only would the auditorium be a possible candidate for wireless, but it also might affect
the routing of wires because it extends several floors in height
Where might you put the telecommunications room on Floor 2? You might consider
using two of them
Floor 3
Floor 3 has large unplanned spaces in Rooms 3.1 and 3.2 If you place the
telecommu-nications room in Room 3.10, how can you serve these spaces, especially the far side
of Room 3.2?
Trang 4972 Appendix A: Structured Cabling
Floor 4 You notice a large deck on Floor 4, as well as a banquet area with a piano What would you need to provide network connectivity to this area?
Where will you put the TR?
You are now prepared to go to work Count up the number of desks that would be served by each of these telecommunications rooms Multiply by two outlets per desk Divide this number by 16, round up as required, and order that many 16-port switches That is your first item for the network equipment list
You will need rack frames to support those switches Order two frames per room to start
Order patch panels to cover the number of specified lines Remember that there is a certain amount of network equipment, such as, switches and routers that must fit in these TRs To calculate accurate totals, consider entering this information into a spreadsheet
Network Cabling You determined how many work-area outlets you needed for each TR in Step 1 Use cabling of a high grade, Category 5e or greater Using a ruler, map out the routes for these runs and then pick off the dimensions Add them all up, round up to the nearest
1000, add 1000, and then divide by 1000 This is how much cable (1000-foot boxes) you need
It is important to pull cable efficiently Avoid trying to get by with too few boxes or reels
or else it may be necessary to duplicate runs Pulling new cable over existing cables may result in damaging the cable that was pulled earlier
There is a trick here Look at drawings called FloorPlan2-Plumbing-and-HVAC-building floor4 This shows the water and air-conditioning duct work Notice that there is both supply and return air The ceiling is not a plenum ceiling You can specify a cable that
is not plenum or riser-rated This will result in considerable savings
Trang 5Construction Requirements
You determined that you needed risers between each floor This requires coring and
requires that the bottom floor will pass through the mechanical space This will require
conduit
You also modified some rooms on the fourth floor by adding the TR
Next Steps
You now are prepared to work your way through most of the rest of the case study
Have fun Relax Remember that the thinking and planning and false starts and
discus-sion with teammates is where the true value of this exercise lies
Summary
The standards are written in a way that will promote performance Following
stan-dards also tends to unify the methods of construction and installation For instance,
the point at which a telecommunications utility enters the premises almost always is
referred to as an entrance facility (EF) The point at which responsibility for the lines
and equipment transfers from the network provider to the user is called the point of
demarcation, or the demarcation point The EF and the demarc usually are installed in
a room created for that purpose, called a telecommunications room (TR) A TR can
have one of several functions A main cross-connect (MC) distributes the signals to one
or more intermediate cross-connects (IC) These, in turn, pass the signal to one or
more horizontal cross-connects (HC), which deliver the signal to the area near the end
user, called the work area
Work must be performed in a way that does not injure workers, the public, or the
envi-ronment Often this requires marking off the work area with signs or cones to warn
passersby Also, ladder safety is an important practice Ensure that ladders are in good
condition, with no loose or broken portions When deploying a straight ladder, secure
it, if possible, near the point where it contacts a structure If possible, have someone
guard the base of the ladder, and by all means make sure that no one can open a door
and knock you off of it In the case of a stepladder, make sure that the feet firmly
con-tact the ground and that the spreaders are fully extended and latched Do not use a
stepladder as a straight one Never stand on the very top of any ladder
Cabling and wiring require tools adapted to the craft, and installers are well advised to
use them and not get by with substitutes Stripping tools take the insulation off pieces
of wire, often in multiple levels to accommodate installing connectors Cutting tools
cut off pieces of wire, often in a way that does not compress the inside of the wires A
Trang 6974 Appendix A: Structured Cabling
termination tool is used to affix a connector to a prepared cable end These basic tools should be part of every installer’s kit, but perhaps more important are tools for diag-nosis A cable tester gives an indication that every pair is going to the correct place and that each wire is going to the correct terminal
As the cables are pulled into place, it is important to keep in mind that firewalls must not be penetrated unless the equipment is available to restore them to their original condition The fire-stopping tools and materials that do this vary but generally consist
of materials that are certified to resist the spread of smoke and flame Following the rough-in phase, cable is routed, terminated, and set into patch panels and cover plates
in the trimout and finish phases The finish phase is also the time during which cables are tested or certified Certification consists of passing specialized signals through a cable to determine whether the amounts of frequency-specific attenuation and head-room are within tolerance Certification results usually are presented to the building owner as part of the cabling plant documentation
There are no cabling jobs to be had if bids are not won, and accurate bidding requires
a thorough site survey and careful estimating Labor regulations and union restrictions might affect the timing of a project and should be taken into account The external fac-tors of each job can greatly affect the amount of profitability that is expected
The study presented in this material involves using a company’s written requirements and a set of blueprints to develop the necessary plan, estimates, and documentation for
a network installation in a four-story office/warehouse complex
Trang 7Key Terms
ANSI American National Standards Institute
backbone A pathway or cable that runs between telecommunications rooms (TRs)
and buildings
blueprint An architectural plan or technical drawing that provides details of a
construction project or an existing structure
bullwheel A large-diameter pulley that is used in a mechanical cable-pulling process
cable tree A device that supports a number of small reels of cable This enables the
cable installer to pull multiple runs of cable simultaneously
CENELEC Comité Europe en de Normalisation Electrotechnique, or European
Committee for Electrotechnical Standardization
crosstalk The signal from a transmitting pair being coupled to the receiving pair or
other pairs in the cable Crosstalk occurs most frequently near the transmitters in a
circuit
demarc The point at which the service provider’s cable interfaces with the building
distribution cabling
demarcation point Usually the point at which the access provider’s facilities stop and
the customer-owned structured cabling begins
equipment room Space for equipment Also can be used as a telecommunications
room
HC (horizontal cross-connect) Area where patch panels or punchdown blocks are
used to connect cables from work areas to the MC The HC can be a
telecommunica-tions room, a cabinet, or a floor or ceiling installation
IC (intermediate cross-connect) The connection point between a backbone cable
that extends from the MC to the HC
MC (main cross-connect) The cross-connect that normally is located in the primary
telecommunications room or the equipment room
MSDS (material safety data sheet) A document that contains information on the
use, storage, and handling of a hazardous material It provides detailed information
on the potential health effects of exposure and how to work safely with the material
multimeter A testing tool used to ensure that no voltage is on the telecommunications
line Most of these devices can measure AC/DC voltage, current, resistance, diode,
continuity, and transistor
Trang 8976 Appendix A: Structured Cabling
MUTOA (multiuser telecommunications outlet assembly) A device that holds multi-ple outlets for use in work areas where modular furniture is used Computers and tele-phones are plugged directly into the MUTOA
NEC National Electrical Code
NFPA National Fire Protection Association
OSHA Occupational Safety and Health Administration
patch cable A cable with a connector on each end, used to transfer signals from one piece of network equipment to another
patch cord A length of cable used to connect links at the cross-connect
patch panel A device used to interconnect data networking or voice systems to the physical cable network The rear of the patch panel has network cables that are punched down The front of the patch panel has a factory-terminated interface of some type
plenum An open ceiling that acts as an air-return duct for heating, ventilation, and air-conditioning systems
raceway Channels that contain cables in an installation Raceways include common electrical conduit, specialized cable trays or ladder racks, in-floor duct systems, and plastic or metal surface-mounted raceways
SCS (structured cabling system) Integrated cable plans that include the connectors, wiring, distribution centers, and installation techniques developed by specific companies
structured cabling A uniform cabling system with standards that define the actual cable, cabling distances, type of cable, and type of terminating devices
TDR (time domain reflectometer) A device that can measure the lengths of cables that are installed and locate faults It does these tasks by sending a signal down a cable and then measuring the amount of time that it takes for that signal to return
TIA Telecommunications Industry Association
TR (telecommunications room) The area within a building that houses the telecom-munications cabling system equipment
vertical cabling Backbone cables, intermediate and main cross-connects, mechanical terminations, and patch cords or jumpers used for backbone-to-backbone cross-connections
work area A space where computers, telephones, and other network equipment is used