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.

1.0 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.

1.1 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).

1.1B) 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).

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).

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:

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 cabling system.

For additional design information and the industry's first FREE web study course on patch-cord management click here.