I-O DATA HFAS1-XS20U Setup Manual page 11

Using a USB hub and two USB HDD units.
If you use a USB hub, you can connect two USB HDD units, one for shared use and one for backup use.
* We recommend a type of USB HDD that is connected to an electrical outlet for most types of USB hub.
* Even if you connect two or more USB HDD units for the same application (for shared use / for backup
use), you will not be able to use them.
* For details of the backup function, please see
2.3.3. Removing the USB HDD
If you want to remove a USB HDD when the power to this unit is on, please do so with the
following operation 2.2.3. Removing the USB HDD (page
Go to [Table of Contents]
2. Getting More out of this Unit – 2.3. Streaming Music on a USB HDD as it is
"2.7. Backing Up Music (page
8).
11
17)".