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Jumper management is often an afterthought for many system designers, but it can turn out to be one of the more critical decisions a designer has to make. Jumper management can affect the required rack space, floor space and ease of system management, which often are the requirements for a successful system design.

The ability to complete quick and easy moves, adds and changes of equipment often is aided by designing the system in a star topology as required in ANSI/EIA/TIA standards 942 and 568-B.1. The star topology described in TIA-942 requires that all backbone cabling in the fiber-optic system return to a main cross connect in the main distribution area, where equipment connections can be made via jumpers.

For larger fiber-optic systems, many cross connections are required in the main cross connect, often within limited rack and floor space. Density in the backplane has been improved with the use of ribbon cables and 12-fiber MTP/MPO ribbon array connectors. The use of preterminated breakout modules and panels incorporating these high-density MTP/MPO connectors facilitates a greater density of fibers coming into the rack. This increased density can create the problem of jumpers coming off the front of the rack that are greater in number and density than what system designers had to deal with in the past.

This large increase in the number and density of jumpers creates a new challenge to the system designer. ANSI/EIA/TIA-942 provides the system designer with several recommendations and requirements for jumper management in the racks. In addition, designers should ensure that the cables can be dressed neatly and that bend radius requirements specified in 568-B.2 and B.3 are met.

ANSI/EIA/TIA 942 allows for the use of 19” or 23” racks. The standard requires that single racks have vertical cable management on both sides of the rack and that cable managers are at least 3.25” wide, with 6”-wide cable managers being the preferred solution. The vertical cable managers should extend from the floor to the top of the rack. The standard also recommends, for a row of racks, to consider 10”-wide vertical cable managers in between racks and the standard 6”-wide managers on the end of each row.

Vertical jumper-management guides are often equipped with a variety of features for increased flexibility, increased jumper protection and ease of use. Moveable radius jumper-management guides with rounded sides are often implemented to provide minimum bend radius protection. Hinged jumper retaining doors are added to hold jumpers in place, while still allowing easy access to the jumpers when necessary.

Grommeted holes are often included on the units to allow jumpers to easily pass through from the front to rear of the rack. Cable-management guides on the rear of the rack are typically removable to allow the system designer the flexibility of running conduit or inner duct into patch panel housings or equipment. Removable covers are often available for the vertical management guides to allow for a complete, organized and neat appearance of installation.

The 942 standard recommends that horizontal cable management be installed above and below each patch panel, and that overhead cable trays be used for management of patch cables between racks. The use of overhead trays and reduced-diameter, high-fiber-count optical backbone cables under the floor reduces congestion in the areas under the raised floor, allowing for increased air flow and more efficient cooling of the equipment located within the racks.

Installing horizontal cable management above and below each patch panel can take up a lot of the valuable rack space that system designers are now so often required to preserve. To combat this issue, manufacturers have developed ways to get the most horizontal jumper management within the available rack space, while maintaining the jumpers’ minimum bend radius.

One approach to deal with the issue of jumper management is to integrate horizontal jumper management to the top and bottom of the patch panel housing. This adds increased flexibility without increasing rack space or reducing connector capacity. With the addition of removable, larger, front, lower cable-management rings, increased quantities of jumpers can be run along the bottom of the unit without using any additional rack space.

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This article was provided by David Hessong of Corning Cable Systems, Hickory, N.C.