SPECIFICATION FOR THE
PATCH-CORD MANAGEMENT SYSTEM
The goal of developing a bid specification is
to provide a complete end-to-end Structured Cabling System (SCS)
with specifications that incorporate both initial installation
and future maintenance concerns. This is so the SCS can have optimal
performance throughout its life cycle.
In bid specifications, there is typically limited
direction provided to the patch-cord management system. This,
in turn, results in rapid deterioration in the performance and
appearance of the SCS over its life cycle.
This specification has been developed to be incorporated
into a UTP and/or multi-mode fiber-optic SCS proposal to prevent
problems that typically occur over the life cycle of a patch-cord
management system. This will reflex positively on your firms'
knowledge of this subject not only upon initial installation of
the management system but for entire life of the system.
The logic of this specification is formulated
on the basis of an industry study on patch-cord management systems
(excerpts of which were published in Cabling Installation &
Maintenance, February 1997, BICSI NEWS, January '97,
and Structured Cabling & Connecting Systems, summer '97).
The rationale of each step of the bid spec is provided below in
italics so as to increase the understanding of the heretofore-neglected
part of the SCS.
A new element to patch-cord management has been
added called "patch-cord adjusters." A Patch-cord adjuster is
a mechanical device to which a patch-cord is mated that enables
the cord to be managed within the patch field, the bend radius
of the cable to be controlled, and allows for periodic re-adjustment
of the length of the patch-cord. (The PerfectPatch
is a patch-cord adjuster).
This bid specification has been tailored for an
open rack environment although the majority of the specifications
can be applied to cabinets, which are more restrictive. Look forward
to future patch-cord management bid specifications that are detailed
to cabinets and wall fields.
Patch-Cord Management System
The manner and care in which a patch-cord management
system is implemented is a significant factor in the performance
and ease of a system's administration. All the components for
routing and controlling patch cords in a management system are
essential elements to be incorporated in the design and installation
of the structured cabling system.
1.0) By providing these specifications, you prevent
losing control of the management system (the rat's nest), which
decreases network performance because it takes longer to identify
and rectify faults and loose connections.
Horizontal Management for the Patch-Cord Management System in
the Equipment Rack(s)
1.1A) Patch Panels and Managers: Mount a horizontal
manager above and below every 96-port panel (8-position/8-conductor
modular connectors or fiber optic connectors) or combination thereof.
This horizontal manager shall have a height 2RMS (3.5"/8.9cm)
and a minimum depth on the rings or channel of at least 3" (7.62cm).
This type of manager shall be for the management of patch cords,
routing from the interface of the patch-cord plug and the patch
panel(s), into the horizontal manager which will route the patch
cords to the vertical management system. When there are more than
96-ports in either single or multiple patch panels, a horizontal
manager shall be used to separate patch panels and shall be shared
between patch panels (see figure 1).
1.1A)A 96-port panel will give you the optimum
density when using patch-cord adjusters for controlling patch
cords along with the use of horizontal management. Patch panels
should be installed or grouped into 96-port density for uniform,
easy management. This will provide more space in the rack for
additional panels and equipment. The horizontal manager of choice
for optimal performance and easy use with patch cords in combination
with 96-port patch panel would be 2-RMS in height and a minimum
depth of 3 inches (7.62cm). This provides less snagging when modular
plug tips are removed from the horizontal manager. This size of
manager will allow more freedom to add or remove patch cords.
1.1B) Chassis-type concentrators: In equipment
rack where chassis-type concentrators (hubs) are used and the
height on the chassis can range up to 30" in vertical distance
and modular port density exceed 96 ports, horizontal management
shall be used on the top and bottom side. Horizontal managers
shall be shared between patch panel and concentrator
1.1B) The chassis-type concentrator can take up
extensive space in a rack with no horizontal management for patch
cords. That is why patch-cord adjusters must be used on patch
cords to provide a functional system. Otherwise, you will encounter
port status lights covered by the unmanaged patch cords and possible
loose connections. Patch-cord adjusters will make patch cords
taut and extend to their limit without the use of horizontal management.
Patch-cord adjusters will also reduce loose connections that are
typically found in this area due to the lack of horizontal management.
1.1C) Stackable concentrators:
These concentrators should be put into 96-port groups when possible,
and have horizontal managers on the top and bottom side as directed
for patch panels. Horizontal managers shall be shared between
patch panel and stackable concentrators.
1.1C) Stackable concentrators typically will
come in 1-RMS size that can go from 12- to 24-ports in density.
Keeping your port count to 96 before utilizing horizontal managers
will make it easily manageable with the patch panels.
1.1D) Fiber Optics: The horizontal management
shall be self-contained within the fiber patch panel enclosure.
1.1D) Fiber Optics: typically fiber patch-panel
enclosures will be constructed with a front horizontal tray and/or
covers for protection of fiber patch cords. If not, it is recommended
to incorporate this type of enclosure for protection of the fiber
interface; otherwise you will have to share a horizontal manager
in the same fashion as concentrator (see 1.1C).
1.2 Vertical Management
for the Patch-Cord Management System in the Equipment Rack(s).
The vertical management shall have a minimum of
25-sq. in. (161 cm2) of inside usable capacity space. This will
provides less restrictive on patch cords and prompt faster identification
and easier management.
1.2) Vertical Management Systems are clearly
more problematic than horizontal ones. The majority of brackets
and channels on the market today are simply incapable of accommodating
a high density of patch cords in the vertical management system.
One reason is the cumulative effect of patch cords routing vertically
from patch panels to concentrators. It should be noted that larger
vertical managers (min. 25 sq. in) would provide the capacity
to prevent the restriction typically associated with patch cords
in the vertical management system.
1.2A) Single rack: At the transition point between
the premises patch panels and equipment ports, a minimum of one
vertical manager (min. 25 sq. in) will be placed on the left and
right side of the horizontal manager. This vertical manager shall
have enough capacity to handle patch cords with patch-cord adjusters
for all planned and future ports, active and inactive.
1.2A) By providing large-capacity
managers at the transition point between the premise's patch panel
and equipment ports, you will have a distinct routing path for
your patch cords, avoiding the overflow condition associated with
small and inadequate vertical management.
1.2B) Side-by-Side racks: The same procedure shall
be followed as with the single rack (1.2A) with an addition, providing
adequate spacing between racks for vertical management.
1.2B) Side-by-Side standard EIA-rack will provide
no space between racks if mounted together for vertical management
of patch cords. This must be avoided for proper vertical management
(see Installation Tip #4).
1.2C) Side-by-Side Vertical Channel-Type Racks:
Racks are permitted to be placed side-by-side only when there
is enough capacity in the vertical channel to accommodate patch
cords (as in 1.2A).
1.2C) Side-by-side Vertical Channel-Type Racks
must be large enough not to restrict patch cord movement in the
channel. A problem that will typically occur is when racks are
sharing a vertical channel, which dramatically increases the patch
cords and reduces the vertical channel capacity. The key is to
specify each rack individually with its own management system
then attach racks together when required or double the inside
usable capacity of the vertical management (i.e., 50 in2).
Adjusters for Each Patch Cord.
Patch-cord adjusters are used to eliminate the
slack associated with patch cords and to increase the patch-cord
management system's efficiency and appearance over the life cycle
of the system. TIA/EIA-568-A standard-compliant patch-cord adjusters
shall be provided for each patch-cord supplied.
1.3) Typically the patching and management
of these systems is a end-user function. To manage these systems
a tool must be provided that can eliminate the three major patch-
cords problems, which cause poor management over the system's
life cycle. These problems are as follows:
a) Eliminate slack in each patch cord - It is
the accumulated amount of slack in all patch cords in a management
system that has devastating effects on the performance and aesthetics
of the system.
Horizontal and vertical managers will not eliminate
patch cord slack in a management system they will only route the
slack to different areas. The patch-cord adjusters are the only
tool when combined with horizontal and vertical managers that
can eliminate slack. This allows you to custom fit each cord and
maintain performance of Category 5 UTP, 5e(enhanced), proposed
6, or fiber-optic cords in a channel, as required by the TIA/EIA-568-A
or the proposed ISO/IEC 11801Category 6/Class E channel standards.
b) Eliminate patch-cord entanglements - A condition
that occurs when someone relocates a patch cord, and instead of
pulling it out completely and starting over, they simply unplug
the patch cord and stick it into the new port on top (intertwined)
of other cables.
Upon relocation of a patch cord in a management
system, utilizing patch-cord adjusters will require the end-user
to pull the patch cord out completely and adjust the cord to fit
perfectly into another port (about a 30-second operation). This
key function eliminates entanglements, slack and also creates
a self-maintaining management system. Each time an end-user relocates
a patch-cord with patch-cord adjusters applied they also take
care of the management of the system.
c)Training - A quick
easy method of training staff for installing and maintaining patch-
cords for the life cycle of the management system.
Training staff in patch-cord management is historically
a difficult (if not impossible) task. With the use of patch-cord
adjusters the attention is focused on each patch cord. It takes
just a few minutes to grasp how to install a patch-cord adjuster
before it becomes second nature (about 30 second install). Now
IT/Telecom management can explain how to use this inexpensive
tool to control and monitor the management system .See
Patch-cord Management Analysis for details
Each individual patch-panel port shall be labeled
in numerical order and shall correspond to cables terminated at
each four-pair insulation displacement connection (IDC) and/or
fiber optic connector on the back of a patch panel, reflecting
the same work area or backbone cable numbers. Concentrator ports
may be labeled at the discretion of the customer.
labeling patch panels in numerical order, you
will increase the customer's ability to identify cables. This
is an area that should be reviewed at the completion of installation
for exactness, because if one number is out of sequence it can
throw off the entire numerical order of a patch panel.
In conclusion, we have provided the elements for
success in a patch-cord management system: horizontal managers,
vertical managers, patch-cord adjusters, and labeling. If even
one of these elements is missing you will seriously jeopardize
the performance of the system. By providing the management controls
up-front in the bid specification you will bring attention to
this little-talked about, but highly visible area of the structured
For additional design information and the industry's
first FREE web study course on patch-cord management click here.