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Thread: power requirements for 2 USB hubs (urgent)

  1. #1
    Variable Bitrate ramy_zohair's Avatar
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    power requirements for 2 USB hubs (urgent)

    I know the VIA M10000 MB has 2 backpanel USB 2.0 ports. Is it possible to connect 2 X 4 port USB 2.0 hubs, making those 8 port. I will be using a lot of self powered USB devices such as TV/FM receiver, GPS mouse, Blutooth, Wifi dongle, OBD II ....and so on. I will also be using the M1-ATX for more (90W).

    Do all these USB powered devices consume the same power. Or do some use more considerable power than other, taking in mind that they all get it from the 5V usb cable.

    Will there be any power issues regarding this setup. I have had bad experience with those small self powered USB hubs before regarding power, and so would like to make sure.

    Ramy
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    Raw Wave EsKALad's Avatar
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    IQRA BISMI RABIKA ALATHEE KHALAQ!!! you need to power the hubs in order for this to work out!
    i got dat ***** sittin on 22s! SUPERMAN EDITION!

  3. #3
    Variable Bitrate ramy_zohair's Avatar
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    Quote Originally Posted by EsKALad
    IQRA BISMI RABIKA ALATHEE KHALAQ!!! you need to power the hubs in order for this to work out!
    Nice to know you can speak arabic

    The hubs are bus powered. no power except from the usb cable.
    Something like this


    http://www.radioshack.com/product/in...ub&tab=summary

    I'm not worried about it powering up, i'm worried about it powering up the other bus powered devices (which also can't have separate power).
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    Variable Bitrate StrataG's Avatar
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    Quote Originally Posted by ramy_zohair
    power requirements for 2 USB hubs (urgent)
    Quote Originally Posted by ramy_zohair
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    If you search, you'll find that a USB port can only output 500mA. You'll be drawing 1A @ 5V to the hubs. You then leave each of your devices with 125mA each (500/4). If your devices (which you will need to read the specs) don't require more than 125mA each, then you'll be fine. Otherwise, go with a self-powered (not bus-powered), to power the devices properly.

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    Maximum Bitrate 3onDubs's Avatar
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    Quote Originally Posted by EsKALad
    IQRA BISMI RABIKA ALATHEE KHALAQ!!! you need to power the hubs in order for this to work out!
    ALATHEE KHALAQAL INSANA MIN ALAQ.... ...Does a powered hub offer 500mA to each port on the hub? In other words...if I have a powered hub, can I run 4 seperate usb-powered devices on this hub? Does this depend on how many amps are available on the 5V line powering my hub?
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  6. #6
    Variable Bitrate StrataG's Avatar
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    Quote Originally Posted by 3onDubs
    ALATHEE KHALAQAL INSANA MIN ALAQ.... ...Does a powered hub offer 500mA to each port on the hub? In other words...if I have a powered hub, can I run 4 seperate usb-powered devices on this hub? Does this depend on how many amps are available on the 5V line powering my hub?
    A self-powered (i.e. one that has it's own power input) hub will provide up to 500mA on each port if it is up to spec. So long as your self-powered hub requires at least 500mA * number of ports (plus a little power for it's own operation), it should be able to give 500mA to each port. So the answer is almost definately you can run 4 seperate bus-powered devices on the hub. Keep in mind you will be wasting money (if you will be replacing a bus-powered hub), if your devices don't need more juice. 7-port bus-powered hubs are more problematic as you are splitting that 500mA into 7 devices. Most USB devices don't need more than 100mA, but of course check your hardware specs to be sure.

  7. #7
    Variable Bitrate ramy_zohair's Avatar
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    From what i see, self powered hubs (external power) are better than the bus powered ones (as the supply 500mA to each port instead of 500mA to all of them) if i'm not wrong. The question is how do u power those self powered ones effectively in a car, from a 5V molex connector, or what?? will it be enough??

  8. #8
    Maximum Bitrate DeltaFX's Avatar
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    Written on the powerbrick of a small USB highspeed 4-ports Hub :

    5v, 2200 mA. Soo... 200mA to powerthe hub itself, and 4*500mA for the ports.

    If you plan mixing USB1.1 and USB highspeed devices, make sure all your Highspeed stuff is connected to the same hub, and that all Lowspeed devices are linked to the other hub. That's just a rule of thumb, not all hub can deal with mixed devices, and they'll probably drop down to USB 1.1 if there's a lowspeed device.

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