Allied Telesis AT-SBx81CFC960 - Manual (Page 233)

SwitchBlade x8112 Chassis Switch and AT-SBx81CFC960 Card Installation Guide
Section II: Installing the Chassis 233
Figure 152. Installing a Blank Power Supply Slot Cover
6. Lower the locking handle to secure the slot cover to the slot. Refer to
Figure 153 on page 234.