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Old December 30th 07, 06:44 PM posted to comp.sys.ibm.pc.hardware.chips,microsoft.public.windowsxp.hardware,alt.os.linux.ubuntu,comp.os.linux.hardware
Yousuf Khan
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Posts: 102
Default Generic USB 2.0 hub showing up as USB 1.1

VanguardLH wrote:
Have you visited the manufacturer's web site to get the specs on those
USB hubs? Having the same hardware (i.e., chipset) says nothing about
how the manufacturer utilized that hardware. Lots of analog modems use
the same Conexant chip but the *cards* don't have the same feature set.
Same subsystem components do not enforce the same system features.
Could be one of the hubs really only is 1.1 compliant and that using it
as a 2.0 device is not recommended. Of course, the device could be just
a crappy low-grade cheap unit that doesn't properly respond to report
itself correctly, or you need a better USB cable.


Well, as I said previously, these are "generic" hubs, very generic. I
doubt any of us have heard of the manufacturers' names: there isn't much
point in checking their websites, they probably sell tons of little
products. One is from Vantec and the other is Acrox. The Acrox is the
older more reliable one. Both of them are advertised as USB 2.0 hubs,
and both of them are identified as "USB2.0 Hub" internally, polled from
the USB configuration itself.

Are both of these a self-powered hub (i.e., they have a power adapter)
or a low-power hub that relies on the current supplied from the USB
controller at the motherboard? If they are bus-powered hubs, they
CANNOT be on the same USB controller. Each controller provides 2 ports
(channels) but these 2 ports still share the same controller and so both
are limited by a total amperage that can be supplied by the same
controller.


Both can be self-powered or bus-powered, they have the power inputs.
Only one of them came with an included power cord though. And
surprisingly it's the less reliable one that has the power cord. The
more reliable one doesn't have one. I have tried that one with and
without the power cord, but it made no difference.

I have resorted to putting my fast peripherals on the older hub, such an
external hard drive, a digital camera, and a Skype phone. They all have
their own power cords so they don't need to be powered by the hub
anyways. The hard disk and camera show up under the mass storage device
class.

The slower hub is being used for slow peripherals like mice and
keyboards now.

USB devices are supposed to report their power consumption. Maybe you
hubs don't. Or maybe they report too high a consumption to guarantee
USB 2.0 mode to work so the controller degrades to USB 1.1 mode.


Both are reporting 100mA.

Yousuf Khan
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