Horizontal
Cabling
The definition of
horizontal cabling is that portion of the cabling system that extends from
the work area outlet, through the cabling in the wall/ceiling/floor and then
to the patch panel in the telecommunications room. The system also includes
the patch cords at the work area outlet, and patch cords in the telecommunications
room. When provisioning for the horizontal cabling system the designer should
also consider voice, fire/safety, video, HVAC and EMS.
A good design should be aimed at minimizing relocations and maintenance of
the horizontal system as it is much more costly to do it later.
Topology
Horizontal cabling will be installed in a star topology, with each work area
outlet being connected via the horizontal cable to the horizontal cross connect
in the telecommunications room. Each floor should have its own telecommunications
closet, sized as per ANSI/TIA/EIA 569.
Any devices required such as baluns and impedance matching devices should
not be installed in the horizontal system, but rather, kept external to the
telecommunications outlet. This will facilitate network changes.
Only one transition point or consolidation point between the horizontal cross
connect and the telecommunications outlet shall be allowed, and bridged taps
and splices are not allowed in the copper horizontal.
Cable Length
The maximum distance between the telecommunications outlet and the horizontal
cross connect shall be no more than 90 meters. The maximum length of all patch
cords and jumpers in the telecommunications closet shall be no more than 5
meters, and the total length of all patch cords both in the telecommunications
closet and at the work area shall be no more than 5 meters.
Recognized Cables
a. 4-pair 100 ohm unshielded twisted pair (UTP) or screened twisted pair (ScTP).
b. two or more multimode optical cables, either 62.5/125 or 50/125
150 ohm shielded twisted pair (STP-A) is a recognized cable type but is not
recommended for new cabling installations.
All jumpers, patch cords, equipment cords shall meet all applicable standards
as specified in ANSI/TIA/EIA 568-B.2 and B.3.
When hybrid and bundled cables are used, each cable type will meet the requirements
for that cable type, and the bundled or hybrid cable will meet the specifications
for bundled cables. Both of the above requirements are located in ANSI/TIA/EIA
568-B.2 and B.3.
Telecommunications Outlets
Each individual work area shall be serviced with a minimum of two telecommunications
outlets. One will be associated with voice and the other data. One outlet
will be a 4 pair 100 ohm UTP cable rated category 3 or higher. Category 5e
is recommended. The other outlet will be either a 4 pair 100 ohm UTP category
5e, or 2 multimode fibers, either 50/125 or 62.5/125 micron fibers. All connectors
must meet all ANSI/TIA/EIA 568-B.2 and B.3 requirements.
Grounding
The system must be bonded and grounded as per ANSI/TIA/EIA
606.
Backbone Cabling
General
Backbone cabling provides interconnections between telecommunications rooms,
equipment rooms, and entrance facilities. It consists of the cabling, copper
and/or fiber, the terminations, patch cords, jumper cords, intermediate and
main cross connects.
Backbone cabling is expected to serve the needs of the user for 3-10 years
based on current and future needs.
Topology
The backbone cabling will be laid out in a hierarchical star so that each
horizontal cross connect is connected to the main cross connect or to an intermediate
cross connect and then to a main cross connect. There can be no more than
two hierarchical levels of cross connects in the backbone. No more than one
cross connect shall be passed through between the horizontal cross connect
and the main cross connect. This means that between any two horizontal cross
connects, the signal must pass through 3 or fewer cross connect facilities.
Recognized Cables
The following cables are recognized in the backbone and may be used on their
own, or in combination.
a. 100 ohm twisted pair cable
b. either 50/125 micron or 62.5/125 micron multimode fiber.
c. Singlemode fiber.
All patch cords, jumpers, connecting hardware must meet ANSI/TIA/EIA-568-B.2
and B.3.
Backbone Cabling Distances
The distances in the table below are inclusive of cable, patch cords, jumpers
and equipment cable.
Maximum Backbone Distance
Media Type Main to Horizontal Cross Connect Main to Intermediate Cross Connect
Intermediate to Horizontal Cross Connect
Copper (Voice) 800 m (2,624 ft) 500 m (1640 ft) 300 m (984 ft)
Multimode Fiber 2000 m (6560 ft) 1700 m (5575 ft) 300 m (984 ft)
Singlemode Fiber 3000 m (9840 ft) 2700 m (8855 ft) 300 m (984 ft)
Jumper and Patch Panel Lengths
Main cross connect jumper and patch cords should not exceed 20 meters. Intermediate
cross connect jumper and patch cords should not exceed 20 meters.
Equipment jumpers should not exceed 30 meters.
Grounding and Bonding
Grounding and bonding practices as per ANSI/TIA/EIA 607 should be followed.
Work Area
General
The work area components are those that extend from the work area outlet to
the telecommunications device(s).
100-Ohm Balanced Twisted-Pair Telecommunications Outlet/Connector
Each 4 pair cable shall be terminated on an 8 position modular jack, and all
UTP and ScTP telecommunications outlets shall meet the requirements of IEC
60603-7, as well as ANSI/TIA/EIA 568-B.2 and the terminal marking and mounting
requirements of ANSI/TIA/EIA-570-A.
There are two recognized pin out assignments, T568A and T568B.
Optical Fiber Telecommunications Outlet
Horizontal fiber shall be terminated in a duplex outlet meeting ANSI/TIA/EIA
568-B.3. The 568SC was specified in ANSI/TIA/EIA 568A-A and is still recommended.
As well other connectors such as some small form factor connectors may be
used.
Work Area Cords
The maximum length of a work area patch cord is 5 meters. Generally, the patch
cord will have similar connectors on each end. If additional devices are required,
such as adapters, they will not be part of the horizontal cabling system,
but rather be connected via the patch cord.
Open Office Cabling
The open office cabling recognizes that some offices are faced with regular
reconfigurations and require a more flexible cabling system to facilitate
these changes.
Multi-user Telecommunications Outlet-MUTOA
The MUTOA is used where there are frequent changes in office layout. The MUTOA
allows the horizontal cable to remain undisturbed while allowing office rearrangements.
The work area cables originating from the MUTOA are connected directly to
the station equipment without the use of any additional connections.
The MUTOA:
1. Should be located in an area so that each furniture cluster is served by
at least 1 MUTOA.
2. Should serve a maximum of 12 work areas.
3. Will have a maximum work area cable length.
4. Shall be attached to a permanent part of the building
5. Shall not be located in the ceiling or furniture, unless that part of the
furniture is permanently affixed to the building.
Administration
The MUTOA is are administered as in ANSI/TIA/EIA-606. The work area cables
connecting a MUTOA to a device are to be assigned a unique identifier and
the cable shall be labelled at both ends. The outlet end shall identify the
work area it serves and the work area end shall identify which MUTOA it is
connected to, and what port on the MUTOA.
When a MUTOA is used the horizontal cable maximum length will be affected,
based on the length of the work area cord. The maximum length of the work
area cord is 22 meters. For purposes of calculating the horizontal cable and
the work area cord, the formula is:
C = (102 - H)/(1 = D)
Where:
C = maximum combined length of the work area cable, equipment cable and patch
cord
H = the length of the horizontal cable (H + C < 100)
D = the derating factor for the patch cord type. (.2 for 24AWG UTP and ScTP,
and .5 for 26 AWG ScTP)
There is a second formula for calculations which is not shown here.
Maximum Work Area Cable Length
Length of Horizontal Cable Maximum Length of Work Area Cable Maximum Combined
Length of All Patch and Equipment Cords
Meters (Ft) Meters (Ft) Meters (Ft)
90 (295) 5 (16) 10 (33)
85 (279) 9 (30) 14 (46)
80 (262) 13 (44) 18 (59)
75 (246) 17 (57) 22 (72)
70 (230) 22 (72) 27 (89)
For fiber optic cables, a reduction of the total 100 meters is not required.
Consolidation Point
A consolidation point is an interconnection point within the horizontal cabling
using compliant connecting hardware. It requires an additional connection
point (telecommunications outlet). Cross connects cannot be used at a CP and
no more than 1 CP is permitted in a horizontal run, nor can a CP and transition
point be used in the same horizontal run. The CP should be located a minimum
of 15 meters from the telecommunications room to reduce the effects of NEXT
and return loss.
The CP should be located in a fully accessible and permanent location.
Administration of the CP should follow ANSI/TIA/EIA 606.
Telecommunications Rooms
General
Consult ANSI/TIA/EIA 569 for design and provisioning requirements for telecommunication
rooms.
The telecommunications room may contain horizontal cable, backbone cable and
their connecting hardware, intermediate cross connect or main cross connect
for portions of the backbone system. The TR also provides environmental control
for the telecommunications equipment and splice closures as they relate to
the building.
Cross Connection and Interconnection
All connections between horizontal cabling and backbone cables shall be cross
connects. All connecting hardware and cables shall meet the requirements of
ANSI/TIA/EIA 568-B.2 and B.3.
An interconnection will connect the connecting hardware of the horizontal
cable (patch panel) to the telecommunications equipment (eg: hub).
A cross connect will have the connecting hardware of the horizontal system
(eg: patch panel) connected to connecting hardware (patch panel), which is
in turn connected to the common equipment.
Equipment Rooms
Equipment rooms differ from telecommunications rooms in that the ERs generally
contain more complex equipment, but an ER may also be a telecommunications
room. Equipment rooms must conform to ANSI/TIA/EIA 569 requirements.
An equipment room may also contain main cross connects, the intermediate cross
connect used in the backbone hierarchy.
The ER may also act as a telecommunications room and house the horizontal
terminations, telephone provider terminations, premise network terminations
and other miscellaneous terminations.
Entrance Facilities (EF)
General
The entrance facilities serve as the entrance point for the outside plant
cable from a variety of sources such as the telephone company, private network
cables and other access providers. It also houses network protection devices,
and may act as the demarcation point for the regulated access provider.
The EF must conform to ANSI/TIA/EIA-569 requirements.
Functions
Network Demarcation
The EF may be the demarcation (termination point) for the regulated access
provider(s) and private network providers(s). Local regulations will determine
where the demarcation point will be.
Electrical Protection
Interbuilding cables and antennas may require devices to protect from power
surges. The designer/installer should consult the local access provider to
determine local practices and requirements.
Grounding and bonding should be completed as per ANSI/TIA/EIA 607.
Connections
The EF contains the connections and transition points between the cables designated
for outdoor use and cables designated for indoor use.
Cabling Installation Requirements
Cable Placement
Cable should be placed in such a manner as to minimize stress caused by suspending
the cable and cinching the cable too tight. If cable ties are used, they should
be cinched loosely to prevent deforming the cable sheath.
Balanced 100-Ohm Twisted Pair Cabling (UTP and ScTP)
Minimum Bend Radius
Cable Type Bend Radius
4 Pair UTP 4 X cable diameter
4 Pair ScTP 8 X cable diameter
Backbone 10 X cable diameter
Patch Cords Under Review
Maximum Pulling Tension
For 4 pair UTP it is 110 N (25 lbf). For multipair, consult the manufacturers
specifications.
Connecting Hardware Termination
Cables should be terminated with connectors of the same category. Connecting
cable and components of the same category is not enough to ensure performance.
Other factors such a proximity to power cords, termination practices and cable
management are jus some of the factors that may affect performance.
In a system with multiple category components, the system shall be rated as
that of the lowest performing component.
Only strip back as much jacket as required to properly terminate the cable
on the connector. With Category 5e and higher systems the individual pairs
should not be untwisted more that ½". Category 3 systems the pair
twists shall be maintained to within 3" of the terminations.
Patch Cords
Patch cords should be of the same category as the link, and should not be
field terminated. Jumper cords should not be made by removing a jacket from
a previously jacketed cable.
View Category 5e Modular Cord Transmission Parameters
100-Ohm ScTP Grounding
The drain wire on ScTP cable shall be bonded as per ANSI/TIA/EIA 607.
Optical Fiber Cable
Minimum Bend Radius and Maximum Pulling Tension
No Load Condition* Maximum Load*
Intrabuilding 2 or 4 Fiber 25mm 50mm
Intrabuilding Backbone 10 X OD 15 X OD
Interbuilding Backbone 10 X OD 20 X OD
Note: The maximums are noted here in the abscence of any manufacturers specifications.
Connecting Hardware and Polarity
Optical fiber shall be installed with odd numbered fibers having Position
A at one end and Position B at the other. Even numbered fibers will have position
A and B reversed from the odd numbered fibers. When using the 568SC connector
or other duplex connectors, the above polarity must be maintained.
Patch Cords
Patch cords shall consist of 2 fiber cables of the same fiber type as the
system with connectors at both ends, and shall be positioned A and B as in
the connecting hardware section above, with patch cord A connected to position
B on the connecting hardware, and vice versa for the B position on the patch
cord.
Cabling Transmission Performance and Test Requirements
100 Ohm Twisted Pair
General
System performance is directly related to not only the performance of the
individual components, but also the cable installation practices and the number
of connectors in the system.
TSB 67 is now found in annex D of the original documentation.
Channel and Permanent Link Definitions
The Channel is defined as the 90 meters of horizontal cable, the telecommunications
connector and patch cord in the work area as well as 2 connectors and a maximum
of 2 patch/equipment cords in the telecommunications room. The maximum allowable
length of patch cords and equipment cords is 10 meters. Also included in the
channel is an optional transition or consolidation point.
The Permanent Link is defined as a maximum of 90 meters of horizontal cable,
an optional transition or consolidation point and one connection on each end.
The Permanent Link does not include the instrument cords or connectors on
the field test equipment.
Test Parameters
The primary tests are:
Wire Map
Length
Insertion Loss
Near End Cross Talk (NEXT)
Power Sum Near End Cross Talk (PSNEXT)
Equal Level Far End Cross Talk (ELFEXT)
Power Sum Equal Level Far End Crosstalk (PSELFEXT)
Return Loss
Propagation Delay
Delay Skew
Wire Map
Checks for proper pin to pin termination, and for each of the 8 conductors
the wire map checks for:
Continuity to the far end
Shorts between any two or more conductors
Reversed Pairs
Split Pairs
Transposed Pairs
Any other miswiring
Length
The physical length of the cable is the actual length derived by measurement
of the cable(s) between the two end points. The electrical length is the length
derived from the propagation delay of the signal and depends on the construction
of the cable.
The maximum physical length of the horizontal cable (permanent link) one end
of the cable to the other is 90 meters. The maximum length of the channel
model is 100 meters.
Insertion Loss
Insertion loss is the loss derived from inserting a device into a transmission
line. The insertion loss for both the permanent link and the channel models
are the total insertion losses of all the components.
Pair to Pair NEXT Loss
Pair to pair NEXT loss is the measurement of signal coupling from one pair
to another. The result is based on the worst pair to pair measurement.
Power Sum NEXT (PSNEXT) Loss
Power sum NEXT takes into account the statistical crosstalk between all pairs
while energized. This is a calculated amount derived by adding up the crosstalk
results between all pair combinations.
Pair to Pair FEXT and ELFEXT Loss
FEXT is the unwanted coupling of a signal induced by a transmitter at the
near end, measured on the disturbed pair at the far end. ELFEXT is the same
measurement of FEXT, less the effect of attenuation.
Power Sum FEXT and Power Sum ELFEXT
As in Power Sum NEXT, these are computed values based on the sum of all the
possible pair combinations under the respective tests.
Return Loss
Return loss is the value of energy reflected by impedance variations when
devices are inserted into the cabling system.
Propagation Delay
Is the time it takes the signal to travel from one end of the cable/system
to the other. The maximum channel propagation delay is 555ns (nanoseconds)
and for the link it is 498 ns, both measured at 10Mhz.
Delay Skew
Delay skew is the signalling delay difference in time (nanoseconds) between
the fastest pair and the slowest pair. The maximum channel delay skew is 50
ns, and in the permanent link it is 44 ns.
Optical Fiber Transmission Performance and Test Measurements
Link Segment
An optical fiber link includes the connectors, splices (if required) and the
passive cabling between two optical fiber connecting hardware termination
points. There are 3 backbone link segments:
MC to IC
MC to HC
IC to HC
Link Segment Performance and Measurement
The most important field test in fiber optic systems is link attenuation.
The horizontal link segments should be tested in one direction at either 850
nm (nanometers) or 1300 nm. The result shall be less than 2.0 dB. In an open
office with a consolidation point, the resulting test shall be less than 2.75
dB, or if using a MUTOA, the result shall be less than 2.0 dB.
Backbone Link Measurement
The backbone shall be tested in at least one direction at both 850 and 1300
(multimode). For singlemode, the links should be tested at 1310 nm and 1550
nm. Because of the possibility of splice points etc, the link attenuation
equation should be used to compute the loss value.
The equation is:
Link Attenuation = Cable Attenuation + Connector Insertion Loss + Splice Insertion
Loss
Note: All calculations, equations, and reference test parameters can be found
in the original documentation, available through TIA.