In message 
          Chris Green  wrote:

> Scott Alfter  wrote:
> > In article , Chris Green  
> > wrote:
> > > All I'm saying is that the USB standard doesn't provide even 2 amps.
> > > Thus a 'USB' cable that conforms to the USB specification doesn't need
> > > to be able to carry that much current.
> > >
> > > If a Pi requires more than the USB specification allows then its power
> > > supply *and* cable are "more than USB".
> >
> > We blew past the 500 mA limit long ago, well before the introduction of
> > the Raspberry Pi.  The iPhone was out 5 years earlier and needed 1 A for
> > full-rate charging.  By the time the Raspberry Pi was introduced, there
> > was a rather large field of devices needing 1, 1.5, 2, or more amps to
> > run and/or charge.  The tricks used to signal current draw with only
> > passive components have even been added to the USB specs, so they really
> > aren't "more than USB," as you put it.
> >
> No, but a USB 2.0 cable that also has data lines really only has to carry
> 500mA to be 'to spec.'.

Sorry, but that simply isn't true.  The USB specs say quite a lot about
USB cables - it's all freely available to the general public, so I
recommend that you download at least one of the specs and read the
section on cables.

You may well realise, after you do so, that lots of "USB cables" out
there really don't conform with the USB specifications.  A lot of them
are clearly too thin.

David

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