Cisco cBR-8 Installation Instructions Manual page 13

c) Insert a minimum of four screws per bracket on both sides of the chassis.
Step 8 Ensure that all the screws on each of the side rack-mount brackets are tightened to the equipment rack before the chassis
installation bracket is removed from the rack.
Figure 7: Two-Post Rack Mounting
What to Do Next
Attach the cable management bracket.
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