What does APC recommend for configuring an APC USB UPS and Multiple USB Devices?
Back-UPS and Back-UPS PRO
Peripherals: If you are using a ""self-powered"" USB hub* to connect your USB peripherals to your PC, APC recommends plugging that hub into the Battery Backup outlets. Otherwise, when there is a loss of power, the hub and its connected peripherals will no longer function. This will inhibit the system shutdown initiated by the UPS or the user.
*A ""self-powered"" hub is defined as a hub that gets its power from the wall outlet as opposed to getting its power directly from the PC's USB port.
APC USB Compatible UPS: APC recommends when using any kind of external USB hub, that the UPS USB cable be plugged directly into a USB port located on the PC itself ( also known as the root hub). This will ensure communication will not be lost.