Unpowered USB hub range

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I am wondering if unpowered usb hubs are able to extend the range of
usb beyond 5 meters or if that is only possible using one with an
external "ie. wall wart" power supply. That is, I would like to first
connect a 5m cable to the computer, then a hub, then another 5m cable
and finally the peripheral in question, for a total of 10m cable.


//Regards, Johan.

Re: Unpowered USB hub range

On 24 Apr 2007 10:53:03 -0700, armatic@gmail.com wrote:

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Yes they are.

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Yes providing all devices work as USB specs, it is do-able.

Re: Unpowered USB hub range

armatic@gmail.com wrote:
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http://www.usb.org/about/faq/ans3 /

   "You may connect high power devices to self powered hubs only
    and low power devices to either bus or self powered hubs.

    High power devices are devices that draw more than 100mA from
    the USB power line, low power devices are ones that draw 100mA or less."

And this page addresses the reach question, using hubs and cables.


If you use your proposed scheme, of a bus powered hub for a repeater,
then the end device is limited to <100mA loading. So no high
powered device apparently. A hub with its own power supply
will be a more capable solution, for a source of DC power.

Check the label on the USB device. You could also use UVCView to
check the current rating of the device itself, when the device
is connected directly to your computer.


Re: Unpowered USB hub range


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Are you overlooking the possiblity of a bus-powered repeater
hub, connected to a self-powered end hub to which the high
powered devices are plugged into?  

I'm not sure how Windows would interpret this though, if it
would be logically accepted as a high powered device with
the bus powered hub in the middle.

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