Charging USB devices with Fedora

[Kari Somby]

Don Quixote de la Mancha kirjoitti keskiviikko, 17. maaliskuuta 2010 11:42:14:
> On Wed, Mar 17, 2010 at 2:28 AM, Kari Somby <familyzombie at gmail.com> wrote:
> > It can be something on your USB device or USB port.
> 
> To clarify, your motherboard may not be applying device power to your
> USB ports.  I don't think USB power is actually required by the
> protocol spec, rather its an optional feature.  Even if power is
> provided, the amount provided may be insufficient for your particular
> device.

That's parly true. The protocol says that max current for one USB host is 500 
mA. 
I even have USB -> phone adapter enabling charge my cellphones using USB port.
There are 4 wires in USB cable: 0V, +5V, +data and -data (if I remember 
right).
Almost forgot, I have USB LED light. A simple bright LED that gets its power 
from USB port.
 
> > When using USB purely powering purposes, no drivers are needed - only
> > thing is that USB devices are enabled.
> 
> That's usually the case, but its not true in general.  To charge a
> Motorola RAZR from USB, one needs special software.  There are several
> freeware packages that enable RAZR charging.  I only tried on Mac OS
> X; I don't know whether there is a Linux package that does it.

This must be software for the Motorola RAZR. 
i.e. computer driver sends information to RAZR that it can now charge it's 
battery.

--
Kapi