USB HUB Questions!

Discussion in 'Mac Peripherals' started by Macnator, Oct 14, 2008.

  1. macrumors 6502

    Hey everyone.

    I have a Belkin 7-Port USB Hub. Now my question is this:

    The included power supply, is it absolutely necessary? Would everything work fine if I just connected the USB Hub to my computer with the included USB cable? Would devices connected to the Hub function improperly?
    (I have an iMac if that helps)

    Thanks for your help! I really need to know what to do here.
  2. macrumors 68020


    The answer to that depends on what particular devices you have attached to the hub.

    Only low power devices (generally keyboards and mice for example) will work correctly with a non-powered hub as the USB port the hub is connected to can only supply limited power to the hub- far less per hub port than the provided AC adapter does. 7 port hubs only make the demand more important than it is for 4 port hubs.

    Hard drives, scanners and printers, while they are generally powered by their own A.C. supplies, generally do not work well or at all with a non-powered hub. Portable hard drives (i.e. 2.5" bus powered hard drives commonly used with laptops) will not work with a non-powered hub at all.

    Your results will simply be a result of testing it with your devices, though I can't imagine having a power adapter supplied and not using it (with the five hubs I use anyways)- I just don't see the upside unless we are talking about laptop usage. Another thought is that if the AC adapter were not necessary you can be sure that the manufacturer would not provide one! ;)
  3. macrumors 603

    I bought a new laptop cooling fan that has 4 USB ports. I tried plugging in my My Passport HDD (which gets all of it's power via USB) to one of those ports. I instantly got some undervolt message, which means it wouldn't work. So I had to plug it into the MacBook Pro's port. Meanwhile, syncing my iPhone and charging it works fine using these ports. So like the other guy said, it all depends. My guess is you're fine for most stuff that isn't just like my hard drive. The big stuff that uses USB (printers, scanners) has seperate power. Just test what you have.
  4. macrumors 6502


    Like the previous answer intimated, use lower-powered devices with the Belkin unplugged from its AC power, but power it on for the heavier-demand devices. As a rule of thumb, the only unpowered USB devices I use are flash drives, keyboard and mouse.

    sickmacdoc ... top-shelf answer!
  5. macrumors 68020


    Thanks- and that is a very good point about flash drives too. I had forgotten about them being another low power device that will work from a non-powered hub successfully.

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