Asus AP1720-E2 - Manual (Page 78)

Chapter 3: Installation options 3-2
The items required for the optional configurations described in this
chapter are not included in the standard barebone system package.
These items are purchased separately.
3.1 Installing a second SCSI drive cage
Perform this installation if you wish to upgrade your 4-SCSI configuration
system (AS4 model) to an 8-SCSI configuration (AS8).
To install a second SCSI drive cage:
1. Position the drive cage in the
same orientation as the first drive
cage. Note that the lock tab on
top of the cage faces the rear
panel.
Clear the space under the first SCSI drive cage. Make sure that you
disconnect all pre-connected cables so they do not get in the way
when you install the second drive cage.
2. Carefully slide the drive cage
toward the front panel until it fits
in place.
Cage lock tab
AS4 AS8