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  • Three USB quesitons...

    1) If I buy an small, externally powered USB hub, will it still draw power from the mobo usb port if cut the hub's power supply? What about devices connected to the hub? My computer provides 5V to the USB ports when in standby and I'm wondering if I can control the hub's devices by shutting off the hub's power.

    2) What are the chaining rules for USB? Can I connect a hub to the mobo, then chain a hub from that? How about chaining another one from that second one?

    3) Why do I want a powered vs. non-powered hub? What types of devices work well with each kind?
    My worklog.
    Status: VM GTI sold, got out of the CarPC tinkering hobby, but I still think about getting back in.

  • #2
    1&#176 Yes, probably. Some hubs can work as USB-powered when xternal power is off. They will use power even if there's nothing connect to them.

    2&#176 If I remember well, you cant daisy-chain more than 127 periphs. Chaining 3 hubs should work, butI'd rather avoid mixing différent brands. Remeber some usb devices don't work when connected to a hub (can't negociate their power needs with the puter) Example : ZIP250 USB-powered drive.

    3&#176 USB-Powered : you are limited to 500mA to share between all your USB devices minus 10-20mA for the hub's electronic itself. Good for Kbd, mices, tsk, usb-sticks.

    X-ternally powered : 500mA for each port it provides, good for hungry webcams, dvd/hdd/zip/click drives....
    Now Galileo is real. Muhahahahaha :p

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    • #3
      1) Yes. If you cut the hub's external power it will then attempt to be an unpowered hub powered from the computer.

      2) Yes, go for it.

      3) Use powered to avoid hassles.

      -arebelspy
      See my trades here! My For Sale/Trade Thread. Email joe at eipse.com
      Originally posted by xdjxklusivex
      i think every thread is now a whoreing thread

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      • #4
        Originally posted by arebelspy
        1) Yes. If you cut the hub's external power it will then attempt to be an unpowered hub powered from the computer.
        I'm worried about draw during standby. Well not that worried since I do it. In any case, what's a rough estimate (or exact if you have measured specific gear) of what the hub itself might draw.
        Example:
        mobo -> Powered hub -> GPS

        When I remove the power, and put the mobo in standby, how much will the hub draw above the GPS draw (which I've measured at about 30mA).
        My worklog.
        Status: VM GTI sold, got out of the CarPC tinkering hobby, but I still think about getting back in.

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        • #5
          Do you have an extra PCI slot? If so, you can buy a USB PCI card which will cut power when the computer goes off
          2005 Black Chevy Impala
          Current Status: Installed in Vehicle/Testing 75%

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          • #6
            Originally posted by Shelbrain
            Do you have an extra PCI slot? If so, you can buy a USB PCI card which will cut power when the computer goes off
            Not right now, I've got a PCI wifi card there. But, that's an good idea.
            My worklog.
            Status: VM GTI sold, got out of the CarPC tinkering hobby, but I still think about getting back in.

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