Archived from groups: alt.comp.hardware,alt.comp.hardware.pc-homebuilt,uk.comp.homebuilt,alt.comp.hardware.homebuilt (
More info?)
"Tim Auton" <tim.auton@uton.[groupSexWithoutTheY]> wrote in message
news
5pq70lh2lct7aejahh8sjlfg72at6d74o@4ax.com...
> "Alex" <me@privacy.net> wrote:
> >"DCA" <MAPSdca860@MAPSntlworld.com> wrote in message
> >news:tlNec.16$KC6.12@newsfe1-win...
> >> "Piotr Makley" <pmakley@mail.com> wrote in message
> >> news:94C9D878D1A1A31E75@130.133.1.4...
> >> | What is the maximum current or power which the USB specs say can
> >> | be drawn from a USB port?
> >>
> >> 500mA I believe
> >
> >Or 100mA for:
> >
> >- a downstream port on a bus-powered hub,
> >- a port on a root port hub on a battery-powered system (possibly), or
> >- a downstream port on a battery-powered self-powered hub (possibly).
>
> - a port which doesn't think it's talking to anything (according to
> the spec anyway, in reality you can often get 500mA or more just by
> hooking up to the power lines).
True, but in normal operation this is a temporary state of relevance only to
developers of USB devices. And maybe hubs... are they supposed to limit the
current?
Alex