3/03 • 1260151 application note Overview Today’s optical transmission equipment can transmit astonishing amounts of data, video, or telephone conversations. Additionally, better technology has resulted in densely populated Fiber Optic Terminal (FOT) equipment frames. These two factors added together make the fibers at the FOT very valuable. However, up to now, the emphasis on managing these fibers has been minimal. In the past an equipment frame may have only accommodated a few fibers. Now these frames commonly accommodate 20, 40, or even more than 100 fibers. Consequently, quickly finding the right fiber to change service is not as easy as it used to be. Searching for a fiber in a packed raceway increases the likelihood that service on an adjacent fiber is disturbed. Thus, physical protection is mandatory for fibers entering and exiting the FOT. In addition to physical protection, increases in transmission speed require strict controls on a fiber’s bend radius. Simply coiling a fiber and stuffing it into the vertical raceway makes it difficult to ensure an appropriate bend radius. Inducing a tight bend in a fiber may result in an attenuated signal, meaning bit errors, poor video quality, or dropped calls. Higher density and higher bandwidth dictate that complacency is no longer acceptable. Avoiding service outages means managing and protecting fibers. Product Description ADC’s Fiber Management Tray (FMT) series of fiber panels provides the kind of management necessary in today’s environment. This application note will discuss the features of the FMT panels and describe their use in real world applications. ADC’s FMT products provide bend radius protection and physical protection in a 1.75-inch high panel. The FMT comes in several styles: storage, termination, termination/storage, and termination/splicing/storage. The all-front-access trays feature sliding radius limiters for error-proof slack loop management and 30 mm bend radius protection within the tray. Sliding adapter packs allow easy access for connecting jumpers and cleaning connectors, ensuring that any fiber can be installed or removed without inducing a macrobend on an adjacent fiber. The trays are lockable, further ensuring integrity of the fibers by greatly reducing the chance for accidents. The FMT also provides a large blank label on the front of the drawer to easily accommodate the office technician’s labeling needs. By placing the label in this position, a technician can glance over the termination assignments without even opening the drawer. Applications Slack Storage at the FOT An FOT frame may service dozens or even hundreds of fibers. It is very difficult to determine an exact jumper length between the FOT and the fiber distribution frame (FDF) that will not result in slack somewhere in the path (see Figure 1). Even if the perfect length is determined, it is perhaps even Fiber Management Trays 3/03 • 1260151 RF Worx Cable Management more difficult to ensure that this jumper length is always in stock. When an emergency arises, a technician may have to use a longer jumper. This will inevitably result in leftover slack that must be stored and protected. In this scenario, there are two options: store the slack at the FDF or store it at the FOT. Most FDFs do not accommodate equipment jumper slack very well. Attempting to store slack at the FDF could congest cable management not intended for storing slack. This is not an option in today’s world, in which high density is the norm. Congested cable management prematurely exhausts space needed for future fibers, thus robbing the FDF of its true potential. On the other hand, some FDF systems provide slack management features for FOT jumpers. However, these solutions may be stand-alone panels that require additional floor space alongside the frame. Some network planners are not willing to give up this floor space. The second and perhaps most economical method to store this slack is back at the FOT frame. ADC’s storage-only FMT occupies just 1.75-inches of rack mounting space. The discrete storage drawer features 16 flip-up trays that can store between 1.7 and 2.5 meters of jumper slack, depending on the diameter of the jumper. Each fiber is assigned its own tray and is easily accessible for service changes. The bulk storage drawer, as shown in Figure 2, features bend radius limiters arranged in an open fashion, which allows storage for a larger quantity of jumpers. The bulk storage FMT provides up to 2.5 meters of slack for as many as (48) 2mm jumpers, fast becoming the standard jumper size in fiber networks. Using two bulk storage FMTs, which are stackable, and 2mm jumpers, a technician can safely and cleanly store slack for up to 96 jumpers in only two rack units. www.adc.com • +1-952-938-8080 • 1-800-366-3891 2 OSP Cable Splice Protected by dedicated fiber protection system Intrafacility Fiber Cable Protected by overhead Fiberguide, Fiber Management System Equipment Jumper Connector Module Connector Module Interbay Management Panel Storage Fiber Management Tray Fiber Optic Terminal Fiber Distribution Frame Fiber Optic Terminal Bay Fiber Entrance Cabinet Figure 1 Figure 2 3/03 • 1260151 RF Worx Cable Management Routing Multifiber Cables from the Network Element Maintenance is a troubling issue resulting from the increase in fiber counts. Moves, adds, or changes to service on a particular fiber may require working to access a long jumper in the overhead or under-floor fiber protection system. This time-consuming task can require more than one technician, making installation and maintenance costs a heavier burden than they need to be. Many network planners try to alleviate this problem by using multifiber cables as a means of connecting network elements to fiber distribution panels or frames. This may be done within the confines of a Local Exchange Carrier’s network or when handing off service to a competitor located in a collocation cage. This practice is also common at the customer premises, where several panels within the building are connected to a main distribution frame. The rationale behind this practice is that routing one cable through the office is more cost-effective than routing potentially dozens of jumpers across this same space. While this may be true, eventually the individual fibers need to break away from the outer cable jacket. Providing adequate protection for these vulnerable fibers introduces a new problem. Or, the cable may need to be spliced at the network element; finding a convenient place at which to protect and store the splice becomes an issue (see Figure 3). www.adc.com • +1-952-938-8080 • 1-800-366-3891 3 OSP Cable Splice Fiber Entrance Cabinet Protected by dedicated fiber protection system Intrafacility Fiber Cable Connector Module Connector Module Interbay Management Panel Storage Fiber Distribution Frame Protected by overhead Fiberguide, Fiber Management System Multi-fiber Cable Assembly Equipment Jumper Fiber Management Tray Fiber Optic Terminal Fiber Optic Terminal Bay Figure 3 The FMT termination/storage panel is ideal for this application (see Figure 4). A multifiber cable can be clamped to the equipment frame while the individual fibers are routed inside the FMT and protected by its bend radius limiters. The termination/splicing/storage panel is ideal for situations in which a stubbed cable is required. Instead of routing a terminated cable through a riser, for instance, many installers feel that using a stubbed cable eliminates the chance of breaking a connector while threading the cable through the conduit. In this scenario the stub cable can be clamped to the equipment frame. The individual fibers are then routed inside the FMT and spliced to factory-terminated and -loaded pigtails. The slack management spools provide another benefit. Because of the range of slack that these spools can accommodate, a standard jumper length can be used to interface with any equipment chassis on the frame. This simplifies inventory management and makes services changes error-free. The slack management spools ensure that slack will be protected no matter how hastily a jumper is added when turning up new service. Figure 4 ADC Telecommunications, Inc., P.O. Box 1101, Minneapolis, Minnesota USA 55440-1101 Specifications published here are current as of the date of publication of this document. Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice. At any time, you may verify product specifications by contacting our headquarters office in Minneapolis. ADC Telecommunications, Inc. views its patent portfolio as an important corporate asset and vigorously enforces its patents. Products or features contained herein may be covered by one or more U.S. or foreign patents. An Equal Opportunity Employer 1260151 3/03 Original © 2003 ADC Telecommunications, Inc. All Rights Reserved Web Site: www.adc.com From North America, Call Toll Free: 1-800-366-3891 • Outside of North America: +1-952-938-8080 Fax: +1-952-917-3237 For a listing of ADC’s global sales office locations, please refer to our web site. Conclusion ADC’s Fiber Management Trays meet the need of today’s fiber optic networks. As optical transmission speeds and fiber density increase, cable management becomes a crucial component in maintaining network integrity. Excellent cable management practices and products allow service providers to offer highly reliable services, which is key to retaining current business as well as gaining additional business. . Storage Fiber Distribution Frame Protected by overhead Fiberguide, Fiber Management System Multi -fiber Cable Assembly Equipment Jumper Fiber Management Tray Fiber Optic Terminal Fiber. Jumper Connector Module Connector Module Interbay Management Panel Storage Fiber Management Tray Fiber Optic Terminal Fiber Distribution Frame Fiber Optic Terminal Bay Fiber Entrance Cabinet Figure