SHIELDED CABLE
PERFORMANCE
PARAMETERS
NETWORK CABLE
SOLUTIONS
MODULE 2-J
1
SCREEN TECHNOLOGY

Screening of UTP cables
 Shielded Screened or Foiled
 Known as ScTP in the Americas.
 Low usage
 Known
as FTP in Europe
 80% of installed LAN’s
 Primarily in UK, France, Germany
2
SCREEN TECHNOLOGY

Advantages
 Greater immunity from RFI/EMI interference.
 Yields lower bit error rate.
 Greater immunity from radiated signals.
 Yields a more secure cabling solution.

Disadvantages
 Higher installed cost
 Material and Labor
 Greater difficulty in installation
 Shorter link lengths under certain conditions
3
SCREENED TECHNOLOGY

Two basic construction
 FTP (ScTP)
 Four pair cable with an overall foil shield.
 Drain Wire
 S-FTP
 Four pair cable with individually pairs.
 Overall braided shield.
 Drain Wire
 Similar to the STP cables used in Token Ring applications.
4
SCREENED TECHNOLOGY

100 ohm Shielded cabling Design
 Not 100 Ohm UTP with a shield.
 Shielded 100 Ohm twisted pair is designed to provide
certain system performance characteristics
 It can have a large number of variations.
5
STANDARDS

TIA/EIA 568-A
 Has references to 4 pair, 100 ohm shielded cable
 It is allowed if it meets the same performance
specifications as UTP.
 No description of cable construction.
 No specifications on the connector shield interface.
 No specifications on shielding performance.
 No guideline on how to design or install a system in order to
maintain shielding performance
6
STANDARDS

TIA Task Group
 Formed to fill the gaps and define specific.
 Component Requirements.
 Installation Requirements.
 Task Group Definition
 4 pair to be used as a standard.
 Overall foil shield and drain wire to be the basic
construction.
 Other shields and braids may be added as long as basic construction
is maintained.
7
STANDARDS

TIA Task Group
 Task Group Definitions
 Performance categories are the same as for UTP.
 Color coding is the same.
 8 position jack is maintained.
 Jack to plug shield has been standardized and a test has
been developed to verify shielding performance of a mated
pair.
 Requirements for shield continuity and grounding have been
determined.
8
STANDARDS

ISO/IEC 11801
 More complete than TIA EIA 568A, but has gaps.
 List tentative specifications on cable and connector
shielding performance.
 Provides basic installation guidelines on shield continuity
and grounding.
 Allows both 2 pair and 4 pair.
 Allows 120 ohm impedance.
9
STANDARDS

ISO/IEC 11801
 Allows both:
 Overall shield construction
 Individually Shielded Construction

EN 55022
 This directive defines the limits and methods of
measurement of ratio frequency interference
characteristics of information technology equipment.
 Limits on what a LAN can emit.
 Similar to limit imposed by the FCC in the U.S.
10
STANDARDS

EMC & Cabling Systems
 Unshielded or badly shielded cable cannot pass the
European emissions directive at much more than 30 Mhz
without encoding schemes or filter devices.
 The FCC in the United States limits the transmission
frequency at 30 Mhz
 Through encoding schemes transmission at 31.25 Mhz is
possible because it spreads the energy over a wider
frequency.
11
SHIELDING EFFECT

Emissions
 Screens reduce the radiated signals by a minimum of 20
dB.
12
STANDARDS

EN 55024
 Defines the degree of sensitivity of a system with regard
to the following:
 Electrostatic Discharge Immunity, Part 2
 Radiated Immunity, Part 3
 Fast Transient Immunity, Part 4
 Induced Interference, Part 6
13
POSITION

Strong position in Europe.
 In areas where shielded cabling is used.
 Reflects concerns over more stringent regulatory controls
on electromagnetic emissions.
 Concerns regarding interference from electromagnetic
noise.
 European Community used the term electromagnetic
compatibility (EMC) to encompass both concerns.
14
EMC CONTROL

Shielding is not the only means of EMC control.
 Well balanced Non shielded twisted pair cables are
effective in limiting emissions and interference at current
digital transmission frequencies.
 Electronic techniques are used to limit transmission
frequencies and maintain acceptable bit error rates in
typical office environments.
15
EMC CONTROL

UTP Cable
 EMC control dependent on system balance.
 Balance dependent on pair twist rate.
 Pair twist rate is close to manufacturing minimum.
 Crosstalk performance dependent on variation of twist
length.
 Ability to further improve crosstalk by twist is limited.
16
APPLICATION

Emission
 Emission standards, when tested, are for “typical”
installations which is done in a controlled laboratory
environment field installations may be different..
 Cannot cover all installations variables.

Immunity
 Influenced by nearby machinery and equipment sources.
 Influenced by nearby sources of RFI.
17
ADVANTAGES OF SHIELDING

Advantages
 Take over at point that pair twists leave off and provide
electromagnetic interference control at higher frequencies.
 Individually shielded cables can provided additional immunity
to crosstalk that is not achievable by pair twisting.
18
APPLICATION

Shielded cables are used to augment EMC
characteristics of UTP type cables.
 Provide additional control for critical networks.
 Additional immunity over eletromechanically noisy
environments.
 Can be viewed as an additional insurance policy.
19
LINK LENGTH

Due to the shield a thicker primary insulation is
required.
 To meet the same attenuation and impedance specifications
as that of UTP.
 It is impractical to make a 24 AWG patch cord so that it
will fit modular jacks. In Europe a 26 AWG cord is
allowed.
 Attenuation in a 26 AWG cord can be as much as 1.5 times
higher than a 24 AWG solid cable.
 24 AWG stranded is 1.2 times.
20
CONNECTORS

The trend in the United States and most other
areas is to standardize on the eight position
jack.
 Standardized interface to most LAN equipment.

Other connectors available that can utilize
that of 24 AWG cable.
 Non standard designs.
21
GROUNDING

Two methods of grounding are currently in use.
 Star where one end of the cable is grounded.
 Mesh where both ends of the cable are grounded.
 The mesh type system may cause ground loops if both
grounding points are not at the same ground potential.
 The star grounding configuration is recommended.
22
GROUND LOOPS

Ground Loops if Mesh Grounding is used.
 To assure that ground loops do not occur, measure the
following between the shield and the green grounding
conductor of the outlets servicing the work area.
 Resistance should be less than 3.5 ohms.
 Voltage should be less than 1 VRMS
23
PERFORMANCE TESTING

Performance Testing Standards
 Recently the ISO/IEC 11801 standardized the performance
testing of shielded components in terms of Transfer
Impedance.
 The TIA TSB will also standardize on this method.
 Prior to this manufacturers decided on the method to be
used.
24
SUMMARY

The benefits of a shielded cable system is that
it will minimize the variability of installed
twisted pair cabling balance and add signal to
noise margin.
25
SHIELDED CABLE
PERFORMANCE PARAMETERS
QUESTIONS?
26
FTP CABLE INSTALLATION
NETWORK CABLE
SOLUTIONS
MODULE 2-K
27
FTP INSTALLATION

Scope
 To provide the installer with the guidelines to properly
handle high grade FTP cable during installation.
 Proper handling assures optimum cable performance for
intended present and future applications.
28
FTP INSTALLATION

Construction
 Pairs are twisted more
tightly and built to specific
design constraints in a Cat.
5 cable.
 A precise twist is induced
into the bundled 4-Pairs
prior to jacketing.
 Geometry becomes critical
to maintain performance.
 Damaging or changing the
position of the pairs
adversely affects the ability
of the cable to carry high
data rates.
29
FTP INSTALLATION

Minimum Bend Radius
 Cables exceeding the minimum bend radius will exhibit
degraded performance.
 Returning flawed section to a larger diameter will not
correct the fault.
 the cable will still exhibit the degraded transmission
performance
30
FTP INSTALLATION

Minimum Bend Radius
 Review conduit bends
 Exercise care in installing cable in trays
 Do not bend cable over corners
 Do not coil cable tightly and stuff into work box.
 Store excess coiled in ceiling
 Exercise care when dressing cables
31
FTP INSTALLATION

Minimum Bend Radius
 Sweep cables to avoid bends and kinks.
 Kinking the cable changes the shape of the core, moves the
pairs and changes the geometry
 Damage is permanent

Service Loops
 1-3 feet loops at termination points
 Leave service loops along the route of the cable
32
FTP INSTALLATION

Maximum Tensile Loading
 Exceeding the maximum tensile loading will adversely affect
the performance of the cable.
 Quality of the cable is a affected long before damage is
visible
 Physical stress must be guarded against during installation
and in suspended cable runs.
 Cables should be well supported.
 Correcting cable tension will not reverse the effect of
over-loading.
 Maximum cable loading for an FTP four pair cable is 25 lb.
33
FTP INSTALLATION

Over-Cinching
 Over-cinching causes compression and distortion of the
cable, degrading cable performance.
 Cable ties must never distort the jacket.
 Avoid using staples
 Never crush the cable with staples.
34
FTP INSTALLATION



Avoid using staples
because they crush the
cable
The wraps should not
distort the jacket of the
cable
A properly installed tie
wrap can easily be moved
up and down and twisted
around the bundle
35
FTP INSTALLATION

Over-Cinching
 Select non-compression
cable management
accessories
 Velcro tie wraps
 “D” rings
 Nail on cable clamps
36
FTP INSTALLATION

Cable Bundles
 Assure that weight of bundle in not compressing cable
jacket.
 Exert care when running a large cable bundle around a bend
 In trays fiber cable should be placed on the top and FTP on
the bottom.
37
FTP INSTALLATION

Cable Lengths
 Horizontal runs are limited to 90 meters or less.
 Work area equipment cables are limited to 3 m or less.
 Patch cords, jumpers, and cross connects are limited to 7 m
or less in the telecommunications closet.
38
FTP INSTALLATION

Other Installation Suggestions
 Do not share bore holes with power wires.
 Never install components of unknown or questionable
manufacture or quality.
 Keep wire away from heat sources, heat ducts and pipes.
 Leave one to three foot service loops at outlets and
connection points.
 When existing a cable tray it is recommended that a
service loop is left.
 Use proper support methods when installing a cable in a
dropped ceiling.
39
FTP INSTALLATION

Cable Installation
 Each horizontal run should be a continuous link to a single
work area.
 Bridging of horizontal runs is not acceptable.
 Do not split pairs between multiple outlets.
 All four pairs must be connected to a single jack or
connector.
40
FTP CABLE INSTALLATION
QUESTIONS?
41
FTP CABLE TERMINATION
NETWORK CABLE
SOLUTIONS
MODULE 2-L
42
FTP TERMINATION

Termination of FTP cable from UTP differs in
that:
 Shield continuity must be maintained throughout the
system.
 Shield must be grounded.
43
FTP TERMINATION

Termination Procedures
 Strip cable to expose conductors, drain wire and foil.
 Cut foil even with outer jacket.
 Slip cable over grounding tab. Be sure that the tab is on
the inside of the foil shield.
 Bend drain wire ground tabs against the cable.
 Wrap the drain wire around the tabs and the cable.
 Apply tie wrap to assure good contact of drain wire to
grounding tab.
 Punch pairs down.
 Snap metal shield over connector.
44
FTP CABLE TERMINATION
QUESTIONS?
45
LAN CABLING SYSTEMS
OVERVIEW
NETWORK CABLE
SOLUTIONS
MODULE 3-A
46
LOCAL AREA NETWORK
A Local Area Network or LAN is a system that
interconnects data devices to share
information at high speeds in a limited
geographic area. Accomplished with a
combination of hardware and software.
47
LAN CABLING





LAN cabling provides a path to distribute data
signals
The objective of the cabling systems is to be
reliable and error free
Could be the most expensive component of a
LAN.
May restrict technology.
Important element in high speed LAN’s
48
NETWORK CABLING FACT


70% of all LAN problems are directly related
to the media.
90% of all LAN problems are directly related
to the media and physical hardware.
49
CABLING FACTS
Why you should assure only the best cabling
system is installed in your facility.
50
LIFE CYCLES





Software
PC and Micros
Mainframe
Cabling System
Building Shell
- 1 Year
- 5 Years
- 10 years
- 16 years
- 50 years
51
NETWORK INVESTMENT




Software
Intelligent Workstations
LAN Equipment
Cabling
- 54%
- 34%
- 7%
- 5%
52
DOWNTIME


70% of all downtime is cable related.
Downtime costs run between $1000 to $50,000
per hour
53
SPEED FOR DATA

Past
 1.2 kbps. 9.6 kbps. 19.2 kbps. 4 Mbps.

Current
 10 Mbps. 16 Mbps. 100 Mbps. 155 Mbps. 1 Gbps.

Near Future
 10Gbps, 40Gbps
54
PAST PRACTICES




Cabling usually was an afterthought
Most cabling systems were system specific.
Objective was to spend as little as possible.
Little was known regarding cable technology on
the part of decision makers.
55
CABLING DESIGN CONSIDERATION





What is the current network speed.
Over what distances will the data be
transmitted.
Applicable LAN standards.
What are the applicable fire codes.
What applications will the cable plant need to
support in the future.
56
LAN CABLE CHOICES




Coaxial cable (Coax)
Shielded twisted pair (STP)
Unshielded twisted pair (UTP)
Fiber optic cable
57
COAXIAL CABLES

Construction
 single conductor
 Thick dielectric
 Braided shield



High Bandwidth
Several types
Ethernet LANs
58
COAX TERMINATION

Connector types used on coax
 Thicknet/N type
 Thinner or IBM 3270/BNC type
 Video/F type
59
SHIELDED TWISTED PAIR CABLE

Two types
 IBM type cable
 150 ohm
 Each pair individually shielded
 Overall braided shield
 ScTP or Foiled
 100 ohm
 Pairs not individually shielded
 Overall foil shield
60
SHIELDED TWISTED PAIR CABLE



High Bandwidth
Token Ring
150 Ohm STP cables based on IBM cable types
61
SHIELDED TWISTED PAIR CABLE
62
STP TERMINATION

connector types used on STP
 STP Data connector
 Self shorting
63
UNSHIELDED TWISTED PAIR
CABLE

Construction
 Two to four individually twisted pairs
 EIA/TIA-568 A specifies four pair
 Cables up to 25 pair available
 No shield
 24 AWG solid conductor
 Stranded conductor for patch cords
 Small in size
 Performance defined to 100 MHz
64
UNSHIELDED TWISTED PAIR
CABLE
65
UNSHIELDED TWISTED PAIR
CABLE
66
UNSHIELDED TWISTED PAIR
CABLE

Five categories of UTP cable.
 Category designation indicates cables performance
 In today’s LANs only Category 3 and Category 5 are used
and the Category 5 enhanced
67
UTP TERMINATION

Connectors used in UTP termination
 8 position RJ-45 type modular plug
 used to terminate cables
 8 position modular jack
 Used to terminate cables at wall plate
 Punch down blocks
 Used to terminate cables in closets
 66 blocks
 110 blocks
68
UTP TERMINATION
69
FIBER OPTIC CABLE


Two optical fibers need for a LAN circuit
Several types of coatings and jacketing
 Tight buffer
 Loose tube gel filled
 Multipurpose indoor/outdoor

Bandwidth is unlimited.
70
FIBER OPTIC CABLE
71
FIBER OPTIC CABLE


Developed to meet bandwidth hungry
applications
Transmits any type of signal
 voice, video, data
 analog or digital


Future unlimited
Current limitations due to electronics
72
FIBER OPTIC TERMINATION



Fiber optic cable termination on both ends with
a connector
Connectors joined by barrel connector
Many types of connectors on the market
currently
 ST type most popular
 SC is recommended standard in TIA/EIA-568A
73
FIBER OPTIC TERMINATION
74
LAN TOPOLOGIES

Bus
 Ethernet

Ring
 Token Ring

Star
 TIA/EIA-568A
75
BUS TOPOLOGY

Advantages
 Low cable usage
 Simplified cable management

Disadvantages
 Design Complexity
 Preplanning is a requirement
 Cable failure will bring down the network
76
RING TOPOLOGY

Advantages
 Low cable usage
 Simplified cable management

Disadvantages
 Design Complexity
 Preplanning is a requirement
 Difficult servicing the media
 Multiple potential failure points
77
STAR TOPOLOGY

Advantages
 Easy to design
 Minimal preplanning required
 Simplified servicing and maintenance
 Increased Network reliability

Disadvantages
 Higher cable usage
 Central point of failure
78
NETWORK COMPONENTS & CABLES








Equipment Room
Main Distribution Frame
Telecommunications Closet
Patch Panel
Cross-Connect Block (“66”, “110”)
Hub (MAU)
Gateway
Router, Bridge
79
LAN CABLING SYSTEMS
OVERVIEW
QUESTIONS?
80
LAN TROUBLESHOOTING
NETWORK CABLE
SOLUTIONS
MODULE 3-B
81
LAN TROUBLESHOOTING

If the LAN cabling is in question or has been
determined to be at fault, then the following
steps can be followed to determine what the
specific problem is.
82
LAN TROUBLESHOOTING
1. Find the Cable
 Locate and identify both ends of the cable in question.
2. Is the cable carrying traffic
 With your test equipment check the cable for noise.
Readings in the frequency for the systems topology greater
than 300 mV probably mean the link is active.
 Shut down the link.
83
LAN TROUBLESHOOTING
3. Noise measurement
 Once the link is shut down, the noise measurement should
be carried out again to check for signals from outside
sources.
4. Connectivity
 Check pin to pin connectivity of the cable.
 Look for
 Wiring reversals
 Shorts or opens
84
LAN TROUBLESHOOTING
5. Length
 Next test that should be performed using a hand held
tester or TDR for length.
 Is the length within specification.
6. Impedance
 Using an TDR or a hand held meter test for impedance.
 Ideal TDR plot is a flat line.
 Reflections > +/-10% should be investigated.
85
LAN TROUBLESHOOTING
7. Average and Impulse Noise
 Using wideband AC voltmeter look at frequencies up to
100MHz for activity.
 Background level of 70 mV is acceptable.
 Narrow down the frequency to determine source.
 Low frequencies-AC power, lights, motors.
 Middle frequencies-computer switching power supplies, light dimmers,
medical equipment.
 High frequencies-radio, television, microwave broadcasts or network
traffic (NEXT).
86
LAN TROUBLESHOOTING
8. Attenuation
 Using an injector and a power meter test the cable’s loss
characteristics.
 Test through all patch panels and cross connects and patch
cords.
 Be aware that some shielded cables have high capacitance
and high attenuation at high network speeds.
9. Near End Crosstalk
 Using a hand held tester check for near end crosstalk.
If these tests have negative results the cause of the LAN
failure is all probability not the cable plant.
87
LAN TROUBLESHOOTING

For fiber optic cable the procedure is much
simpler.
 Using an OTDR determine if the length is correct and if
the attenuation is within limits.
 Bandwidth may become an issue if it is an older cable plant.
 Bandwidth cannot be tested in the field with any degree of accuracy.
88
LAN TROUBLESHOOTING
QUESTIONS?
89
LAN DESIGN
CONSIDERATIONS
NETWORK CABLE
SOLUTIONS
MODULE 4-A
90
LAN DESIGN


Standards should be considered with minimum
requirements.
Different customers have different needs.
 Design a system that fits the customer.
91
LAN DESIGN




Work Area Requirements
Closet Requirements
Backbone Distribution Requirements
Horizontal Distribution Requirements
92
LAN DESIGN

Systems Evaluation
 Types of PC’s
 Bandwidth hungry applications
 CAD
 Financial traders
 Video, Multimedia, Teleconferencing
 Modems or fax lines at the desk
 Voice systems
93
LAN DESIGN

Network to be installed
 10Base-T
 100Base-TX
 ATM
 FDDI


Future migration plan
Horizontal Media
 UTP
 Fiber to the desk
 STP
 Special cables
94
LAN DESIGN

Connectors
 T568A or B
 ST or SC or FDDI
 Hardware selection
 Application specific

Network Equipment
 Connections
 Installation options
95
LAN DESIGN

Backbone Media
 UTP
 Fiber
 STP
 Future growth requirements

Distribution
 Horizontal
 Star, Bus, Ring
 Backbone
 Star, Bus, Ring
 Collapsed Backbone
96
LAN DESIGN

Telecommunications Closets
 Size
 Layout
 Construction

Horizontal Distribution
 Cellular floor
 Conduit
 Drop ceiling
 Raised floor
97
LAN DESIGN

Horizontal and Backbone Pathways
 Lengths
 Routing
 EMI sources
 RFI sources
 Fire codes
98
LAN DESIGN

LAN Design Process
 Determine requirements at the work area.
 Outlets
 Media
 LAN Equipment
 Determine requirements for telecommunication closets.
 Space
 Hardware
 Determine Horizontal distribution
 Pathways
 Determine Backbone Distribution
 Pathways
 Media
 LAN Equipment
99
LAN DESIGN

LAN Systems
 Two choices
 Standards Driven
 Technology Driven
 Standards Driven
 Best choice because the LAN will serve the customer for
a much longer period.
100
LAN DESIGN
QUESTIONS?
101
WORK AREA DESIGN
CONSIDERATIONS
NETWORK CABLE
SOLUTIONS
MODULE 4-B
102
WORK AREA

Standards require a minimum of two cables per
area.
 Not necessarily in the same faceplate.
 Pair splitting not allowed.
 One UTP
 Other cable can be
 UTP
 STP
 Optical fiber
103
WORK AREA

Jacks
 Eight position modular jack RJ-45 type.
 Same category as the cable.
 Can be higher category.
 Link category is determined by lowest performing
component.
 Pin assignments per T568A or T568B.
104
UTP/ScTP TERMINATION
105
UTP / ScTP TERMINATION
PIN
1
2
3
4
5
6
7
8
T568A Pair
3
3
2
1
1
2
4
4
Color
W-G
G
W-O
BL
T568B Pair
2
2
3
1
Color
W-O
O
W-G
BL
W-BL O
1
3
W-BL G
W-BR BR
4
4
W-BR BR
106
UTP/ScTP TERMINATION

Selection of termination options.
 T568A
 Corresponds to international ISDN Standard.
 Preferred pinouts in TIA/EIA 568-A Standard.
 Backward compatible to USOC for pairs 1 and 2.
 T568B
 Most widely specified worldwide for data installations.
 Backward compatible to USOC, pair 3 corresponds to pair
2.
 Subset of IEEE 802.3 10BASE-T
 Note
 USOC is a nested configuration on that is the most
commonly used for voice systems in the U.S.
107
WORK AREA

Work Area Hardware
 Must be of equal or higher category as the horizontal
cable.
 Must be securely mounted at planned locations.
 Must be easily accessible.
 Fiber optic connectors that are approved.
 2 simplex SC’s
 2 simplex ST’s
 568SC
108
WORK AREA

Application Specific Components
 Should not be installed as a part of the horizontal cabling.
 Must be outside the faceplate.
109
WORK AREA

Cable Termination
 All four pairs must be terminated to a single connector.
 pair splitting is not allowed.
 Bridged taps and splices are not allowed.
110
EQUIPMENT CORDS

UTP/ScTP Equipment Cords
 Same Category or higher as the horizontal cable.
 Preterminated equipment cords for a Category 5 systems
should be purchased from a qualified supplier.
 Typically the hardware manufacturer.
111
EQUIPMENT CORDS

Fiber Optic Equipment Cords
 Same fiber type as the horizontal cabling.
 Must be a two fiber (duplex) cable.
 Labeling must indicate crossover function.
112
WORK AREA

Multi User Assembly and Consolidation Point
 Must be manageable in size.
 Serve 6 to 12 users.
 Permanently located.
 Work area cables clearly labeled
 Outlet to be marked with maximum allowable work area
cable length.
113
WORK AREA

Locating Outlets
 Coordinate outlet locations with intended floor plan.
 Otherwise 2 outlet boxes per 100 sq ft (10 sq m).
 Mount outlets between 15 in and 48 in (380 to 1220 mm)
above the finished floor.
 Unless local codes differ.
114
WORK AREA

Unterminated Cables
 Stored in outlet boxes with a face plate.
 Face Plate label should identify the outlet box is for
telecommunications use.

Exposed Cable
 Cable installed between the telco closet and the work area
outlet shall not be installed in the work area or any other
space with public access.
115
WORK AREA

Modular Furniture
 Raceways closest to the floor should be used for power
cable.
 Modular furniture with beltways is preferred.
 Belts above desk level are designed for telecommunications
use.
 Under no circumstances should communications cable share a
raceway with power cable without separation.
116
WORK AREA DESIGN
CONSIDERATIONS
QUESTIONS?
117
TELECOMMUNICATIONS
CLOSET DESIGN
CONSIDERATIONS
NETWORK CABLE
SOLUTIONS
MODULE 4-C
118
TELECOMMUNICATIONS CLOSET

Telecommunications Closet
 This is the transition point between the backbone cable and
the horizontal cable.
 Should be dedicated to the telecommunications function.
 Minimum of one per floor.
 Additional closets if:
 The floor area served exceeds 10.000 sq ft (1000 sq m)
 The horizontal distance exceeds 300 ft (90 m)
119
TELECOMMUNICATIONS CLOSET


Recommended closet sizing on a worker area
having 100 sq ft (10 sq m)
Building less than 5000 sq ft (500 sq m) can be
served by a small closet with a minimum size of
2 feet by 8.5 feet (0.6m by 2.6m).
120
TELECOMMUNICATION CLOSETS

Location
 Locate closets near the geographic center of the floor
space that it is intended to serve
 Reduces cabling distances
 Aids in avoiding multiple closets
 Minimum of one closet per floor recommended
121
TELECOMMUNICATION CLOSETS

Closets refer to one of two types of areas
 Main Distribution Frame (MDF)
 Logical center of the Star Topology
 Central control point for cable plant administration
 Hosts devices (mainframe, PBX) located nearby
 Intermediate Distribution Frame (IDF)
 Subordinate to the MDF
 Transition point between Backbone and Horizontal cable
 Control point for local cable plant administration
122
TELECOMMUNICATION CLOSETS

Requirements
 Minimum of two wall covered with plywood.
 No false ceilings.
 Allows for easier cable routing
 Access to the main building grounding electrode
 36 inch by 80 inch (0.91 m x 2 m) door.
 Hinged to open out
123
TELECOMMUNICATION CLOSETS

Requirements
 Electrical
 Two 15 amp 120 volt isolated ground circuits. (Minimum)
 Two 15 amp 240 volt isolated ground circuits. (Minimum)
 Ideal if perimeter outlets are placed every 6 feet (1.8
meters).
 Lighting
 50 footcandles (540 Lx) at 3 feet (90 cm) above the floor.
 Separation
 LAN cable components should not be co-located with
electrical panels or high voltage equipment.
 Do not share with custodial or storage functions.
124
TELECOMMUNICATION CLOSETS

Requirements
 Temperature
 64 degrees F to 75 degrees F
 18 degrees C to 24 degrees C
 Humidity
 30 to 55% relative (non-condensing)
 Heat Dissipation
 750-5000 BTU/hr per cabinet
125
TELECOMMUNICATION CLOSETS

Cabling Practices
 Multiple types of media used in backbones should be cross
connected in the same closet.
 Horizontal cables serving the same work areas should be
terminated in the same Closet.
 Cables should have appropriate cable management and cable
organization hardware to eliminate stress on the cables.
126
TELECOMMUNICATION CLOSETS

Terminations
 Horizontal and Backbone cables must be terminated on
hardware meeting or exceeding the category of the cable.
 Routine moves and changes must not be accomplished by
retermination of fixed backbone or horizontal cables.
 Jumpers or patch cords should be used.
 Application specific devices should be placed outside the
Horizontal Cross-connect.
127
TELECOMMUNICATION CLOSETS

Factory Pre-terminated Patch Cords
 Reduces the performance variations due to field cabling
practices.
 Should be the same category or higher than the cable plant
installed.

Cross Connect
 Jumpers, patch cords, cross-connects, connecting equipment
or backbone cable with horizontal cable should not exceed 7
meters.
128
TELECOMMUNICATION CLOSETS

Equipment Rooms
 Should house only equipment directly related to the
telecommunications system.
 Usually equipment that is common to several floors is
housed in an equipment room.
 Must meet all the same requirements as a
Telecommunications Closet.
 Minimum size 150 sq ft (14 sq m).
 0.75 sq ft (0.07 sq m) per 100 sq ft (10 sq m).
129
TELECOMMUNICATION CLOSETS

Sources of EMI / RFI
 Telecommunications closets and equipment rooms should be
located away from sources of EMI and RFI
 Check for
 Electrical power supply transformers.
 Motors and generators.
 X-ray equipment
 Radio and radar transmitters.
 Photocopy equipment.
 It is not only the copper cable media that is susceptible to
EMI / RFI but also the LAN equipment.
130
TELECOMMUNICATION CLOSETS

Grounding and Bonding
 Must meet all local codes
 Should meet the requirements of TIA/EIA-607
 Grounding points should be easily accessible in all closets.
131
TELECOMMUNICATION CLOSETS

Electrical Protection
 All telecommunications cables that extend outside of a
building is susceptible to extraneous voltages or currents.
 Exceptions are all dielectric optic cables.
 It is recommended that Secondary Protection be installed
on all cables that exit the building to protect electronic
equipment.
132
TELECOMMUNICATIONS
CLOSET DESIGN
CONSIDERATIONS
QUESTIONS?
133
HORIZONTAL DESIGN
CONSIDERATIONS
NETWORK CABLE
SOLUTIONS
MODULE 4-D
134
HORIZONTAL

Considerations
 Cable plant should facilitate ongoing adds, moves, changes,
and maintenance.
 Should accommodate current use requirements.
 Should be designed to accommodate future equipment and
service changes.
135
HORIZONTAL

Standards Recognized Horizontal Media
 TIA / EIA 568-A
 100 ohm Unshielded Twisted Pair (UTP).
 150 ohm Shielded Twisted Pair (STP).
 62.5/125 um duplex optical fiber cable.
 ISO 11801 and TIA/EIA 568-A
 100 ohm Screened Twisted Pair (ScTP).
 a.k.a. Foil Twisted Pair (FTP)
136
HORIZONTAL

Composite, Hybrid Cables
 In horizontal applications it is acceptable to use composite
or hybrid cables as long as each individual cable under the
shared sheath exhibits standards compliant performance.
 Crosstalk requirements are more stringent than for
individual cables.
137
HORIZONTAL

UTP
 Advantages
 Low cost
 Simple installation
 Supports most applications
 New applications are designed for use with UTP
 Disadvantages
 Susceptible to EMI/RFI
 Distance limitations
138
HORIZONTAL

STP/ScTP/FTP
 Advantages
 Good EMI/RFI immunity
 Disadvantages
 Difficult to install
 Higher installed cost
 Improper shield and grounding installation can result in the
cable acting as an antenna
139
HORIZONTAL

Optical Fiber
 Advantages
 Immune to EMI/RFI
 Unlimited bandwidth
 Longer distances
 Supports all applications
 Ease in testing
 Disadvantages
 Longer installation time
 Highest installed cost
140
HORIZONTAL

Topology
 Standards approved topology is the Star.
 Each workstation has its own cable terminated at the
horizontal crossconnect in the telecommunications closet.
141
HORIZONTAL

Selection of Horizontal Media
 Minimum of two telecommunications outlets must provided
for each individual workstation.
 One outlet must be supported by a four pair 100 ohm UTP
or ScTP (FTP) cable.
 Per the standard maximum of a Category 3 is required and a Category
5 is recommended
 Other
media.
outlets can be supported by any of the recognized
142
HORIZONTAL

Distance Limitation
 UTP cable is limited to 295 feet (90 meters) in the
horizontal.
 Optical fiber is limited to 295 feet (90 meters) when hub
equipment is located in each telecommunications closet.
 Optical fiber cable is limited to 984 feet (300 meters)
when hub equipment is centrally located.
143
HORIZONTAL

Distance Limitations
 Length of cable referred to in the distance limitation is the
jacketed length not the electrical length
 Two lengths vary because of pair twists
 Telecommunications closet’s span is considered to be a
radius of 200 feet (60 meters)
 Horizontal cables follow pathways
 Slack
144
HORIZONTAL

Service Loops
 It is recommended that a service loop of between 1-3 feet
of cable be left at all termination.
 This is to facilitate servicing those terminations.
145
HORIZONTAL

Cabling Practices
 Connecting hardware must be installed in compliance to local
codes
 Bridged taps are not allowed
 UTP/ScTP (FTP) cable runs must be continuous, without
splices
146
HORIZONTAL

Multi User Assembly and Consolidation Point
 Must be manageable in size
 Serve 6 to 12 users
 Permanently located
 Work area cables clearly labeled
 Outlet to be marked with maximum allowable work area
cable length
147
HORIZONTAL

Consolidation Points
 Only one consolidation point allowed in a horizontal cable tun
 Cross-connections are not permitted at the consolidation
point
 Active equipment is not allowed at the consolidation point.
 Each horizontal cable exiting the consolidation point must
have all four pairs terminated in the same modular jack.
148
HORIZONTAL

Centralized Fiber Optic Testing
 Used in Fiber-To-The-Desk scenarios
 Horizontal runs with UTP are limited to 90m.
 Fiber has increased transmission distance
 Horizontal cables can be installed directly to centralized
“Hub Farms” within the building.
 300 meter maximum distance.
 Three accepted methods
 Pull through
 Through Splice
 Through Connect
149
HORIZONTAL

EMI/RFI
 Cable routing, closet placement and drop locations should be
such as to avoid sources of EMI and RFI sources.
 Detailed in standard EIA/TIA-569.
150
HORIZONTAL DISTRIBUTION

Conduit Types Recognized:
 Electrical metallic tubing
 Rigid metal conduit
 Rigid PVC

Conduit Type Not Recommended
 Metal Flex Conduit
 Cable suffers from abrasion
151
HORIZONTAL DISTRIBUTION

Installation Guidelines
 Maximum run length without pull point 30 meters (100 feet)
 Maximum of two 90 degrees bends between pull boxes or
pull points
 Fish tape or pull cord shall be placed in installed conduit
152
HORIZONTAL DISTRIBUTION

Installation Guidelines
 Conduits protruding through the
Telco Closet should extend 1 to
above the finished floor
 Conduits protruding through the
extend to 1 to 2 inches (25-50
floor
floor should protrude in a
4 inches (25-100 mm)
floor in other areas should
mm) above the finished
153
HORIZONTAL DISTRIBUTION

Installation Guidelines
 Single conduit run extending from a telecommunications
closet shall not serve more than three outlets
 Conduits shall be reamed
 Conduit shall be terminated with an insulated bushing
154
HORIZONTAL DISTRIBUTION

Ceiling Pathways
 Ceiling distribution pathways be fully accessible
 Drywall or plaster ceiling are not allowed
 Minimum of 3 inches (75 mm) is needed between cable
support hardware and the false ceiling. Same Distance is
required between the hardware and the structural ceiling.
155
SEPARATION

Pathway Separation
 Closed metal pathways provide adequate protection from
capacitively coupled (rapid changes in high voltages) in
commercial buildings.
 Closed metal pathways of ferrous induction suppression
material shall be used in areas of high inductively coupled
noise (rapid changes in high current).
 Open or non-metal pathways shall be placed with sufficient
separation.
156
SEPARATION
Separation of Telco Path From </= 480V Power
Condition
Minimum Separation Distance
< 2 kva
2-5 kva
> 5kva
Unshielded power
lines near open or
non metal pathways
5 in.
Unshielded power
lines near grounded
metal path.
Power lines in
grounded metal
conduit near
grounded metal
conduit path.
12 in.
24 in.
2.5 in.
6 in.
12 in.
--
3 in.
6 in.
157
SEPARATION

High Voltage Separation
 Telecommunications cables should have a separation of 10
feet (3 meters) from panels and power carrying voltages of
480 Vrms or greater.
158
HORIZONTAL

Firestopping
 Properly rated firestop systems must be installed to
prevent or retard the spread of smoke, water, fire and
gases through the building.
159
HORIZONTAL DESIGN
CONSIDERATIONS
QUESTIONS?
160
BACKBONE DESIGN
CONSIDERATIONS
NETWORK CABLE
SOLUTIONS
MODULE 4-E
161
BACKBONE

Backbone Planning
 Backbone cable plants should be designed to accommodate
the systems that are currently being used as well as those
that will be in use in the future.
 Planning should consider the changes that are anticipated in
service requirements and system growth for a period of not
less than 3 years and ideally up to 10 years.
 Other factors that must be considered when a Backbone
Cable Plant is being designed are:
 Bandwidth requirements for present and future
applications.
 The number of Work Areas that are served by the
backbone segment.
162
BACKBONE

Topology
 The backbone cabling plant must use the hierarchical star
topology.
 Two hierarchical levels of cross connects are allowed in
backbone cabling.
 Between the horizontal cross connect and the Main cross
connect only one cross connect may exist.
 No more than three cross connects between any two
horizontal cross connects.
 Limitation of two levels in hierarchy limits the size of LAN.
 In large installations (I.e. universities, military bases) the
area should be segmented into smaller components and then
interconnected.
163
BACKBONE

Location
 Main and intermediate cross connects are to be located in
Telecommunications Closets, Equipment Rooms, or Entrance
Facilities.
 Main cross connects
 Ideally located in an equipment room
 Ideally located in the geographic center of the area it
serves.
164
BACKBONE

Recognized Backbone Cable Types
 100 ohm UTP/ScTP four pair cable.
 100 ohm UTP multipair cable.
 150 ohm STP cable.
 62.5/125 or multimode optical fiber cable.
 Singlemode optical fiber cable.
165
BACKBONE

Composite and Hybrid Cables
 In backbone applications it is acceptable to use composite
or hybrid cables as long as each individual cable under the
shared sheath exhibits standards compliant performance.
 Crosstalk requirements are more stringent than for
individual cables.
166
BACKBONE

Media Selection
 UTP and/or ScTP cables may be used in backbone cable
segments that do not exceed 295 feet (90 meters) for
Category 5 applications.
 Segments that are in excess of 295 feet (90 meters)
should utilize optical fiber cables.
167
BACKBONE

Media Selection
 Fiber Optic Cable
 The selection of fiber optic cable assures that high speed
data applications will be supported in the backbone.
 Fiber optic cable also has higher bandwidth in less pathway
space than copper media.
 Fiber optic cable is immune to the effects of RFI and EMI.
 All dielectric fiber optic cables are immune to ground loops.
168
BACKBONE

Growth
 Recommendation is that one fiber pair be provided for each
current application and a 100% growth factor to be added
to the fiber count.
169
BACKBONE

Distance Limitations
 It is important to note that not all current applications will
operate properly over lengths allowed by the standards for
the copper media.
 The standards allowed UTP cable lengths are based on voice
applications. Backbone cable cannot exceed 295 ft (90 m)
for applications with bandwidths equal to or greater than 4
MHz.
170
BACKBONE

Patch Cords
 In applications where bandwidths are less than 4 MHz,
patch cords and jumpers in the Main Cross connect and
Intermediate Cross connect shall be less than or equal to
66 ft (20 m).
 In applications where bandwidths are equal to or greater
than 4 MHz, the patch cords and jumpers are limited to 16
ft (5m).
171
BACKBONE

Planning
 If requirements are unknown, plan for one copper pair for
every 100 sg ft (10 sq m)
 If requirements are known, plan for copper pairs for each 2
pair application and 8 pairs for each 4 pair application
 Provision for growth and back up
 Provide 4 fibers for each 2 fiber application
172
BACKBONE

Service Loops
 Backbone cables terminating at a Horizontal cross connect
should have a 10 feet (3 meter) service loop
 Backbone cables terminating at the main cross connect or
at intermediate cross connects should have at least 33 feet
(10 meters) service loops
173
BACKBONE

Design considerations discussed in the
Horizontal Section
 EMI/RFI Separation
 Pathways
 Firestopping
174
BACKBONE DESIGN
CONSIDERATIONS
QUESTIONS?
175
THANK YOU
176