Is the power supply required to operate the device, or is it only necessary for charging other USB devices?
1529800
I haven't tried charging another device from this but the operation does not need power supply. Simply plugging in to the USB port is sufficient to run all the functions.
1529801
Only to power other USB devices. I regularly use it without power for hard network connection and USB drive.
2275317
It has to get it from the USB because there is no other power supply directly going into it, why is this question even being asked?
1169291
Yes, the USB charging circuit in this outlet does use power even when nothing is plugged in. I tested by wiring a Mastech MS8264 digital multimeter in series with the hot lead that powers the outlet. With nothing plugged into the outlet, the multimeter read 0.42-0.44 milliamps at 120VAC. Note that this is not a true-RMS multimeter; the actual power draw was probably more like 0.66 milliamps. That's less than 1/10th of a watt, which might be so little that it doesn't matter to you, but it is definitely nonzero and does add up over time. For comparison, I also measured a FastMac U-Socket, a competitor to this device. The U-Socket reading showed about 2/3 of the current that this one drew (with nothing connected to either device). I chose to keep this one because it is easier to fit into a gang box and seems to have a sturdier USB port design.
1416837
Although the user manual does not say that it needs a power source, it came with a USB cable. I was not sure why, later I noticed that the device has a mini USB port on the side. I had it connect to my Cable box that has a USB port. The device did not work properly (it kept flickering) without using USB cable. It works perfectly now.
987495
A power supply is not needed. Just plug in the 2 usb plugs to your computer. Power comes from the usb connections. If you don't have 2 usb connectors, try Radio Shack or Best Buy to match the plug needed.
528564
That other answer is not entirely correct. A powered hub can operate on USB power only. It does not NEED to be plugged into AC. It will work the same as an un-powered hub, which will limit you to a total of 500mA of current draw from all ports combined. However, if you use the AC adapter then you will have up to 500mA per-port (2A total). So if you are only going to connect low powered devices, or self powered devices, then the AC adapter can be considered optional. If you need to connect devices that draw more power (portable hard drives, USB powered scanners, burners, etc.) then you would need to use the AC adapter to supply the additional power.
423991
I use it to charge my cell phone without any problems, so far. I have no reason to think it wouldn't work for other usb charging devices since they're maximum power usage would be similar.
577168
I only use it with external power, but I believe I recall reading that it can not be powered by USB.
1112333
from what I understand, it now includes a USB cable to power the device, previous versions included a power adapter. I wish there are more details on what else has been upgraded. (if there are other stuff that is)
1377007
this item is not powered by USB, it comes with it's own power cord. seen in images of the product.
1552695
It is powered by the USB connection and doesn't require an additional power supply. It is not wireless and must be connected with the USB cable.
1458579
Hi Jon,The unit is USB powered. You dont need a seperate power unit. The USB cable is included.
907288
Hi. With this device, you do not need any external power. The device brings it all included and takes what it needs directly from their computer. It works excellently. Regards. Vincent.
377804
I use a powered usb hub. So I can plug many things into the hub and it has it's own power pack. Then I don't overload the onboard power from the pc.
2149499
Just USB powered but I haven't had any issues with it. Albeit, I only use it on rare occasions for work
1111844
There are one cable USB to an -Mini USB (http://en.wikipedia.org/wiki/USB) in the packet. Its Powered by the USB, no need for extra power.
423988
Remember, this is a 4 amp unit. That means that any single device which needs less than 4A to charge, will be charged.... as long as that is the only device attached. If you have other devices attached, they will be drawing some current, usually up to 900 mA for a USB3 device... sooo something like an iPad may not be able to draw enough current. Most other devices should be ok.