Tài liệu RF Signal Management Traditional Splitter/Combiner Installation and Cable Management ppt

5/01 • 1267Basic Chassis Installation Small or Stand-Alone Applications Since the universal chassis is equipped with a cable tie bar at the rear of the chassis, all necessary hardware to

application note

Overview

Successful signal management in headends of the future will be determined in large part by one issue: the ability to manage the dynamic environment of the return path New services such as the addition of multiple channel lineups or narrowcast insertion of telephony, PCS, network management or data services, demand two-way signaling and the development of a robust reverse path At the same time, providing excellent customer service requires a high level of network reliability, often achieved through headend redundancy

To meet these needs, the RF distribution and management infrastructure must be flexible, reliable, and capable of future growth ADC’s traditional splitter/combiner product line meets these requirements, solves many of the headend signal management problems encountered by design engineers, and offers a robust solution that prepares the headend for future requirements This application note will discuss ADC’s traditional splitter/combiner and describe its use in basic, cabinet, and open rack cable management applications

Product Description

ADC’s traditional splitter/combiner products mount in a universal horizontal chassis configuration

As shown in Figure 1, the universal chassis accommodates 2x1, 4x1, and 8x1 splitter/combiner or directional coupler modules, and can be any desired combination

All chassis are 1.75 inches high and mount in 19-inch equipment racks or 23-inch equipment racks with extender brackets (ordered separately)

Figure 1 Universal Panel Mounting Space Required Per Module

2:1 Splitter/

Combiner or Directional Coupler 4:1

Splitter/

Combiner 8:1

Splitter/

Combiner

Rear View

Although not shown in Figure 1, a cable tie bar is located at the rear of the chassis There are

Traditional Splitter/Combiner

Installation and Cable Management

5/01 • 1267

Basic Chassis Installation

Small or Stand-Alone Applications

Since the universal chassis is equipped with a cable tie bar at the rear of the chassis, all necessary hardware

to completely install the chassis in a 19-inch rack and manage the coaxial cables is provided When installing the universal chassis, first determine what type of mounting environment it is to be installed in

If mounting the chassis in a 23-inch equipment rack, attach extender brackets (ordered separately) to the chassis prior to installing the chassis in the equipment rack (see Figure 2)

Figure 2 Chassis Equipment Rack Mounting

Cable Tie Bar

Mounting Screws (2) Screws (2)Mounting

TOP VIEW 23-inch Equipment Rack Mounting

Extender Bracket

Mounting Screws (2)

Extender Bracket

Mounting Screws (2)

Cable Tie Bar

Mounting

Screws (2)

Mounting

Screws (2)

TOP VIEW 19-inch Equipment Rack Mounting

5/01 • 1267

Basic Chassis Installation

Figure 3 Typical Splitter/Combiner Cable Routing

Rear View

Once the extender brackets have been attached to the universal chassis, position the chassis in its assigned rack location and secure with four mounting screws (provided), two on each side Next, install the required type of splitter/combiner module(s) into the universal chassis Lastly, cable the network elements to the splitter/combiner modules When routing the coaxial cables into the universal chassis, it is recommended that the cabling be split between the left and right sides of the equipment rack (see Figure 3)

Figure 3 depicts a sample installation in which two 8x1 splitter/combiner modules have been installed in the universal chassis As shown, signal coaxial cable enters/exits each individual 8x1 module and is routed

up the equipment rack uprights

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Cabinet Cable Management

For Larger Applications

Figure 4 Cabinet Cable Ring Kit SVC-CBL-KIT-C Cable Ring Kit

Figure 5 Cabinet Cable Management

Cable Management Utilizing SCV-CBL-KIT-C Kit

In using this cabinet cable management kit, it is important to understand the type of cable routing practice used within the office If cables enter/exit the cabinet at the top of the cabinet and run in overhead cable ladder, the largest 6-inch ring must be placed at the top of the bay The 5-inch ring should be installed in the middle of the bay with the smallest 4-inch ring towards the bottom (see Figure 4) If cabling enters/exits the cabinet through a raised computer floor, for example, the ring locations must be inverted Assuming that overhead cable routing is used, cable the uppermost chassis first; route the cables through the top cable ring closest to the top of the cabinet (see Figure 5) Cables from the next-lower chassis exit the rack through either the top 6-inch ring or the 5-inch, depending on chassis versus ring placement Continue working down the cabinet, routing cables through the ring most appropriate for the chassis location Route the cables from the lower chassis through the cable ring at the middle of the rack, then through the uppermost ring at the top of the rack as shown

Tie all cables into a bundle before routing them through the cable management rings at the top of the rack All cables must exit the rack through the 6-inch by 6-inch ring at the top of the cabinet

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Open Rack Cable Management

84"

12"

23"

For Larger Applications

Figure 6 Open Rack Cable Tie Bar/Ring Kit SCV-CBL-KIT-E Cable Tie Bar/ Ring

Figure 7 Typical Unequal Flange Rack with 5" Front Guard Box

Before the use of this cable management kit is discussed, a review of a few basic cable management practices for open racks is important Unlike an equipment cabinet which can have a footprint of 24 inches

to 30 inches in depth, an open unequal flange frame typically only provides a 12-inch or 15-inch deep footprint (see Figure 7), including the 2-inch or 5-inch guard box

5/01 • 1267

Ordering Guide

10"

For Larger Applications

When installing equipment in this type of rack, ADC recommends a minimum of 10 inches of bay separation to accommodate the vertical routing of cable As shown in Figure 8, all coaxial cables vertically entering/exiting the universal chassis are routed up the sides of the unequal flange equipment rack Therefore, when two racks are placed side by side, additional room for cable routing must be allowed

Note in Figure 7 that the cable bundle at the top of the equipment rack is substantially larger than at the bottom of the bay Had the equipment rack been mounted on a raised floor, the situation would

be inverted with the large bundle mass at the bottom of the rack For aesthetic considerations, rack filler kits can be purchased to hide the cable bundles when viewed from the front of the equipment racks (see Figure 8)

Figure 7 Rear View/Coaxial Cable Routing

For Larger Applications

Note that the universal chassis cable tie bars have

been removed for clarity The six cable tie bar/ring

assemblies should be evenly spaced to provide for

adequate bay coverage for cable management

Once installed on the bay, the cable tie bar/ring

assemblies provide two separate channels for

routing of coaxial cables within the bay First, the

cable tie bar portion of the assembly mimics the

cable tie bar that ships with the universal chassis

and provides cable management for coaxial cable

entering/exiting the rack Secondly, the rings

attached to the cable tie bar provide excellent cable

management of coaxial cable routing between

universal chassis within the rack Figure 9 provides

a top-down view depicting how coaxial cables are

routed when using the cable tie bar/ring assembly

As with all cable management practices outlined in

this document, the universal chassis divides the

connections on the rear of the universal chassis

into two planes – left and right Each cable bundle

is then routed either to the left or the right hand

side of the chassis At that point, coaxial cables

entering/exiting the rack are routed via the interbay

cable routing channel, as created by the rack

uprights Coaxial cables needing to connect to

other universal chassis modules are routed through

the intrabay cable channel, as provided by the

cable rings Figure 10 shows a side view of the

cable routing

Open Rack Cable Management

Side View

REAR

12"

5"

5"

Cable Tie Bar/Ring Assembly

Figure 8 Open Rack Cable Management

Intrabay Cable Routing

Interbay Cable Routing

Open Rack Cable Management

Conclusion

ADC’s RF Signal Management products meet the needs of today’s broadband RF service provider Quality of

service to the customer is quickly becoming the major differentiating factor between various service providers – and is key to retaining current business as well as gaining additional business Excellent cable management

practices take the worry out of lengthy troubleshooting and problem resolution

Figure 9 Top View – Open Rack Cable Management Detail

Figure 10 Side View – Open Rack Cable Management Detail

Cable Tie Bar/Ring Assembly Universal

Chassis Unequal Flange Rack Upright