Avaya AP-4 User Manual page 75

Additional Hardware Features
10.Insert the screws into the wall plugs. Use a screwdriver to tighten
the screws and attach the Access Point's metal base to the ceiling.
Figure 2-14: Mounting the AP to the Ceiling
Installing the AP in a Plenum
In an office building, plenum is the space between the structural ceiling
and the tile ceiling that is provided to help air circulate. Many companies
also use the plenum to house communication equipment and cables.
Avaya Wireless AP-4/AP-5 User's Guide 2-37