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Thread: USB powered hubs. Problems?

  1. #1
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    Default USB powered hubs. Problems?

    I've got a Belkin powered USB hub, and most of the time it's fine; just sits there, plug things in, they work, no problems.

    But there are a few devices that just HAVE to be plugged into one of the three USB ports on the iMac, directly, and malfunction if you try them through the hub. (For example, the Logitech wireless keyboard/mouse, the Elgato Video Capture device, and an external CD player).

    I just wondered whether there was a way round this, as I'm running out of ports. I tried a 'dongle' hanging out of the back of the iMac, but found it would only support a single external device (of the 'problem' ones listed above).

    Thanks.


    Allen.

  2. #2
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    sounds like a power issue. perhaps your hub doesn't output enough power for these devices.

  3. #3
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    Belkin support says the same thing: they state that each port can provide 500m/A.

    Which is fair enough, except that finding out what USB power each device needs isn't easy. For example, the manufacturer's spec. on the Samsung DVD drive says it uses 6 watts, but no mention of m/A. (It doesn't have a mains lead - just its USB connection).

    Can I have a quick lesson in electricity please?

    Allen

  4. #4
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    And, as a way round the problem, are there powered USB hubs on the market which allow for higher powered devices?

    (Sorry for double-post: for some reason, I can't edit...)


    A

  5. #5
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    Most USB ports are 500mA @ 5V, or 2.5 W


    For future reference Power = Current X Voltage.

    6w seems a little high

  6. #6
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    I'm quoting from the only source I could find on the 6w, which was Amazon's extended product spec.

    Someone's told me that no USB powered port can exceed 500m/A as that's the USB 2.0, and that's it! True or false?


    Allen

  7. #7
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    On most of the powered hubs I have seen there is a switch that can change it from bus powered to electric powered. No power cord needed when in bus mode. In non-bus mode you need the hubs power cord to the wall.

    Does yours have this switch and is it in non-bus mode?

    Any device that has it's own power cord to the wall should not need power from the USB port.

    Make sure it is in fact a USB 2.0 hub and running in 2.0 mode. System profiler will tell you this. if it identifies as 1.0 you can try changing the USB cable or buying a different hub

    The three devices you mention are gonna give you problems no matter how many $$ you spend on different hubs. CD drives and video capture devices are HIGH bandwidth devices and just don't like hubs IMHO. In the past many external CD's required a direct connection. Not sure about yours. Vid capture is even higher bandwidth than CD's. Wireless devices that come with a dongle that goes in your Mac USB port don't usually work in a hub because the dongle and keyboard connect before the Mac has booted and therefore the mac never knows the keyboard is there. That's the story I got from Kensington on a wireless mouse anyway.

    You can try unplugging the dongle and replugging it after the Mac has booted. Or not turning on the hub until after the mac has booted.

    Can you move anything else to the hub? Printers are low bandwidth and no power (have their own power cord)
    Damien,

  8. #8
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    And power isn't that simple......seems to depend on what type of device, and whether or not data is moving. Check it out.

    I would be cautious of any bus powered CD anything....
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  9. #9
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    Mea culpa.

    My Latin isn't good enough to say that I am a complete idiot.

    What's the first thing to check on a Powered USB Hub?

    The clue is in the first word.

    Well, I have learnt several things, most of which you have taught me. The final lesson has been that a Powered USB Hub WILL work without mains voltage, as a sort of USB extension-lead, but will have trouble coping with any other task. (And no, there's no indicator light to say the thing's on - each port lights up when a USB device is connected, whether it has mains going through it or not).

    Excuse me now, while I go and compose a letter of apology to the manufacturer.


    Humbly,


    Allen.

  10. #10
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    Lol

    So was it unplugged or was there a switch in the wrong position? Cause you know, if it was a switch they're pretty tiny and you could blame it on bad eyesight.
    Damien,

  11. #11
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    Plugged in, switched off. Great big mains plug, big mains switch, so the tiny excuse won't wash I'm afraid.

    Defence? Crowded desk, loads of electrics, peripherals, etc., all tucked behind my iMac. I shall take a morning and tidy things up!

    A

  12. #12
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    Well the cost of fixing it was good - except the frustration. Glad it was nothing too serious.

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