Re: Cig lighter to USB for iPhone 3G?

On 21 Nov, 16:25, m...@xxxxxxxxxxx (zoara) wrote:
Ric <infobub...@xxxxxxxxx> wrote:
if I could copy and paste a link from my iphone I would, but engadget
have a preview of a neat little inline adapter that converts old
iPhone charging devices using FireWire power to charge iphone 3g
models that need USB.  About 30 dollars.

I spotted that. Unfortunately it wouldn't help in this case as
(presumably!) the headset's travel cable has connected the correct pins
to power. The cable (and phone) both charge when connected to other USB
power sources.

I have my suspicions that the phone is detecting any power fluctuations
(or something) in the source and just refusing to accept power from
devices it considers unreliable. Probably some kind of safety measure?
So the 'emergency' battery pack that I have that works is giving a clean
5V signal, but the battery pack that doesn't is fluctuating in a way
that iPods and other devices find acceptable but the iPhone turns its
nose up at.

I just need to find a cig/USB charger that someone else has used to
charge the iPhone, or take a(nother) risk buying something that claims
to charge iPhones...

        -z-

--
am forget my password of mac,did you give me
password on new email marko.[redacted]@yahoo.com

It may not just be the iPhone. My last WinMo device (but not previous
ones) was fussy about USB *** lighter adaptors, too. One worked and
charged it, one didn't. Both would charge "dumb" devices though so
the adaptors weren't broken as such.
I did some digging and I believe part of the USB specs cover a
"handshake" when a device would like to draw more current than the
base standard (500mW?). There's provision for some sort of
intelligence so the device can say "I'd like more power - can you
deliver it?" and the host says yes/no.
I suspected this is what was causing the problems. From memory,
hardwiring a couple of USB contacts inside the USB female connector
jammed this to "yes you can" and fixed the problem.

This may be what's happening in iPhone land?
.

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