In article <6Czlf.13779$>, "Bushy"
<ex(underscore)> wrote:
> speaking of current draw through a usb port, does an externally powered usb
> hub provide power to the peripherals attached to it (assuming this is how
> they get their power) even when the computer is turned off? I ask with
> relation to the ipod i have just ordered, which doesn't come with an ac
> power cord, but must be charged through a usb port. Unfortunately, with a
> regular motherboard usb port, i am led to believe the usb port will provide
> no power when the computer power is switched off, and so the ipod will only
> charge if/when the computer is turned on.
>
> Any ideas? For the record i bought the AC power adapter 'accessory' as well,
> but it pains me that apple doesn't provide a means of charging the ipod as a
> part of the package.
>
>
> Bushy
>
On older motherboards, there is an option header called USBPWRxx,
where the xx is the number of the port pair. Selecting the +5VSB
option will leave the USB ports powered when the computer is sleeping.
Some of the newest Athlon64 motherboards, which have a large number
of USB ports, no longer have those headers. I can only guess that
all the USB ports are already set to +5VSB, because I don't see any
additional power management devices on those motherboards.
Plugging a USB mouse that has LED illumination on it, can be
used as a quick means to see if a port has power. I presume the
Ipod has a charging indicator as well ?
No idea on a USB hub. You'd have to test it. Most likely to work
if the USB hub is self-powered with its own brick power source.
Paul
>
> "Patrick Keenan" <> wrote in message
> news:LAtlf.1946$.. .
> > "JB" <> wrote in message
> > news:...
> >>> The PS would make no difference. <
> >>
> >> I take that back. It could make a difference but in my case it would not
> >> as I have enough slack in the available current to take care of what I
> >> have in mind.
> >
> > The external hub w/power supply certainly can make a difference with
> > higher-draw external devices, and can protect the system itself from
> > instability caused by too high a draw on one port (I've had this happen
> > when connecting a 1Amp laptop drive to a port; the hub locked up, but not
> > the system. When this was done on a laptop port, the laptop crashed
> > badly enough to require removing the battery and resetting the BIOS).
> >
> > As resources, the controller chips and ports are going to be found,
> > drivers loaded and resources allocated regardless of whether they
> > physically are located externally or internally, so resource use should be
> > very similar if not identical.
> >
> > Then, there's the convenience factor of having the external hub placed a
> > little closer to hand or just a bit closer to where the gear actually
> > goes.
> >
> > HTH
> > -pk
> >
> >
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