Installation
After you install both brackets in the rack, you must connect the spanner bar on each bracket to the opposite bracket. The spanner bars are required to prevent both ends of the brackets (at the front and rear of the rack) from separating or drifting apart. The cutouts in the brackets are to accommodate the ear brackets that attach to the chassis to the rack. (Refer to Figure 2 on page 4.)
To install the brackets in the rack, you will secure each bracket to a rack post with three
Mounting the Brackets to the Rack Posts
Follow these steps to mount each bracket to a rack post:
Step 1 Measure the space between the inner edges of the left front and right front equipment
Step 2 Measure the distance between the holes in the mounting posts to ensure that it is
18.31inches ( .063 inches). Make several measurements down the length of the posts to ensure they are parallel.
Step 3 Holding the first bracket in the position shown in Figure 10, place the bracket on the inner side of the rack post, with the flanged front edge of the bracket in front of the rack post.
Figure 10 Installing a Bracket on a Rack Post—Left Bracket Shown
Rack post
Flange 
H2289
Cisco 7000 and Cisco 7507