Installing the Mounting Hardware for a Front-Mount Four-Post Rack or Cabinet

If you are installing the router in a front-mount four-post rack or cabinet, you must first install the large mounting shelf, followed by the small mounting shelf and then the spacer bars on the rack. In addition, you must remove the mounting brackets from the chassis.

Table 1 specifies the holes in which you insert cage nuts and screws to install the mounting hardware required in a four-post or cabinet rack (an X indicates a mounting hole location). The hole distances are relative to one of the standard U divisions on the rack. The bottom of all mounting shelves is at 0.04 in. (0.02 U) above a U division.

To install the mounting shelves and spacer bars (see Figure 1):

1. On the front rack rails, install cage nuts in the holes specified in Table 1 for the large shelf and the spacer bars.
2. On the front of each front rack rail, partially insert a mounting screw into the hole containing the lowest cage nut.
3. Install the large shelf on the front rack rails. Rest the bottom slot of each ear on a mounting screw.
4. Partially insert a mounting screw into the top hole in each ear of the large shelf.
5. Tighten all the screws completely.
6. The router is shipped with each spacer bar attached to the rear of each front-mounting flange. Remove each spacer bar by removing the five screws that fasten the spacer bar to the front-mounting flange.
7. Place one of the spacer bars over an ear of the installed large shelf. Position the spacer bar so that its lower edge is just above the installed screw holding the large shelf.
8. Insert a mounting screw into each of the nonthreaded holes in the recesses of the spacer bar to secure the spacer bar. Each hole should have a cage nut behind it.
9. Repeat Steps 7 and 8 for the other spacer bar.
10. Tighten all the screws completely.
11. On the rear rack rails, install cage nuts in the holes specified in Table 1 for the small shelf.
12. On the back of each rear rack rail, partially insert a mounting screw into the hole containing the lowest cage nut.
13. Install the small shelf on the back rack rails. Rest the bottom slot of each ear on a mounting screw. The small shelf installs on the back of the rear rails, extending toward the center of the rack. The bottom of the small shelf should align with the bottom of the large shelf.
14. Partially insert screws into the open holes in the ears of the small shelf.
15. Tighten all the screws completely.

Figure 1: Installing the M120 Mounting Hardware for a Four-Post Rack or Cabinet