USB Hub

[crazyjman]

I'm looking to pick up a usb hub as I am running out of ports on my PC. Can anybody tell me why some require a power cord while other with the same amount of ports don't? Is one better than the other? (I'm running out of power outlets too)

[boogle]

You can pull a lot more out of your wall than your computers power supply. Power strips are cheap. Depends on your boxes supply but getting a usb hub that is powered usually means that all the power being used to power your usb devices is coming from the wall not your box.

[MessianicDreams]

I'm looking to pick up a usb hub as I am running out of ports on my PC. Can anybody tell me why some require a power cord while other with the same amount of ports don't? Is one better than the other? (I'm running out of power outlets too)

Try plugging 5 USB sticks, or multiple buss-powered HDs into a passive USB hub and you'll see why they make active ones

[SonicAlbert]

I prefer powered USB hubs, except the small four port hub I use with my laptop. You can string a lot of devices onto it without having to worry about power issues. Some USB devices suck up a lot of power, not leaving enough for the other units on the hub.

Sounds like you also need to buy a power strip too!

[crazyjman]

Thanks for the replies. For sure I'll get the powered hub. I didn't realize that I could get into power problems otherwise.
As far as needing a power strip, I'm thinking I need a bigger house now too!

[dgatwood]

There are two types of USB devices as far as power management goes: low-power devices and high-power devices. Low-power devices are required to take just a trickle of power. High-power devices are required to start in a low-power mode, then interact with the computer and request a larger power budget. If the computer doesn't have the power, it will reject the request, and the device will not enter high-power mode (and thus won't be accessible).

The power provided on a USB port is limited by the spec. Generally, a USB port can power at most one non-low-power device (and not always even that, depending on how high "high-power" is). You can plug multiple low-power devices in, however.

A passive hub (one that is powered by bus power) can provide power for several low-power devices (some USB keychain drives, most keyboards, most mice, and any device with its own power supply), but it generally cannot provide power for high-power devices (or one at most). Because a powered hub is not constrained by the available bus power, it can power (up to) one high-power device per port on the hub.