iPod charge voltage?

I've got an iPod AC adapter with FireWire connector for charging the iPod.
Since all interface with computers is now via USB, I'd like to adapt this
charger by cobbling together a USB-to-FW cable that connects -- power
conductors only -- from a male FW connector to a female USB connector.

My question is whether these two AC adapters (let's say Apple brand, both)
output the same voltage. I presume so, but that's enough to get me into
trouble.

Any help -- toward this end -- would be warmly received.

Happy Holidays, and
Thanks,
--
John English

> My question is whether these two AC adapters (let's say Apple brand, both)
> output the same voltage. I presume so, but that's enough to get me into
> trouble.

Well, according to this diagram:

http://pinouts.ru/Devices/ipod_pinout.shtml

the iPod has accommodation on its connector for both FireWire power (12vdc)
and USB power (5vdc).

Probably not worth the trouble to change this adapter (change output voltage)
so it will work with the USB cable...

Never mind...

Thanks,
--
John English

> the iPod has accommodation on its connector for both FireWire power (12vdc)
> and USB power (5vdc).

Hmm... according to this paper, both the USB and FW supplies output 12vdc:

http://docs.info.apple.com/article.html?artnum=60939

Which begs the question: how can you plug the iPod-to-USB cable into either a
computer (which outputs 5vdc) and the USB AC adapter (which outputs 12vdc)
and have no problems?

I must have some incorrect information... ?
--
John English

On Wed, 20 Dec 2006 02:00:39 -0800, John E. Has Frothed:

>> the iPod has accommodation on its connector for both FireWire power (12vdc)
>> and USB power (5vdc).
>
> Hmm... according to this paper, both the USB and FW supplies output 12vdc:
>
> http://docs.info.apple.com/article.html?artnum=60939
>
> Which begs the question: how can you plug the iPod-to-USB cable into either a
> computer (which outputs 5vdc) and the USB AC adapter (which outputs 12vdc)
> and have no problems?
>
> I must have some incorrect information... ?

Yes you do. USB is 5 vdc.
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

Meat Plow wrote:
> On Wed, 20 Dec 2006 02:00:39 -0800, John E. Has Frothed:

>> Hmm... according to this paper, both the USB and FW supplies output 12vdc:
>>
>> http://docs.info.apple.com/article.html?artnum=60939
>>
>> Which begs the question: how can you plug the iPod-to-USB cable into either a
>> computer (which outputs 5vdc) and the USB AC adapter (which outputs 12vdc)
>> and have no problems?
>>
>> I must have some incorrect information... ?

> Yes you do. USB is 5 vdc.

It is, but that doesn't imply that the USB-shaped output on Apple's
charger only provides 5v. Presumably the iPod is designed to handle the
higher voltage; perhaps it results in a faster charge? On the other
hand, it seems like a problem waiting to happen as far as plugging in
other USB-powered devices is concerned.

Pete

On Wed, 20 Dec 2006 14:28:22 +0000, Pete Verdon Has Frothed:

> Meat Plow wrote:
>> On Wed, 20 Dec 2006 02:00:39 -0800, John E. Has Frothed:
>
>>> Hmm... according to this paper, both the USB and FW supplies output 12vdc:
>>>
>>> http://docs.info.apple.com/article.html?artnum=60939
>>>
>>> Which begs the question: how can you plug the iPod-to-USB cable into either a
>>> computer (which outputs 5vdc) and the USB AC adapter (which outputs 12vdc)
>>> and have no problems?
>>>
>>> I must have some incorrect information... ?
>
>> Yes you do. USB is 5 vdc.
>
> It is, but that doesn't imply that the USB-shaped output on Apple's
> charger only provides 5v. Presumably the iPod is designed to handle the
> higher voltage; perhaps it results in a faster charge? On the other
> hand, it seems like a problem waiting to happen as far as plugging in
> other USB-powered devices is concerned.
>
> Pete

Guess I misread the OP's post a bit. And yes if the output is 12vdc it
could cause problems with 5vdc USB devices.

--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

> Yes you do. USB is 5 vdc.

Right you are. This Appple doc states the obvious, that the USB power adapter
outputs 5vdc:

http://manuals.info.apple.com/en/iPo...Adapter-EN.pdf

Just a misprint in the original doc.

Thanks,
--
John English

On Wed, 20 Dec 2006 08:39:47 -0800, John E. Has Frothed:

>> Yes you do. USB is 5 vdc.
>
> Right you are. This Appple doc states the obvious, that the USB power adapter
> outputs 5vdc:
>
> http://manuals.info.apple.com/en/iPo...Adapter-EN.pdf
>
> Just a misprint in the original doc.
>
> Thanks,

That's good to know since there was some controversy.
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

Meat Plow wrote:
> On Wed, 20 Dec 2006 02:00:39 -0800, John E. Has Frothed:
>
>>> the iPod has accommodation on its connector for both FireWire power (12vdc)
>>> and USB power (5vdc).
>> Hmm... according to this paper, both the USB and FW supplies output 12vdc:
>>
>> http://docs.info.apple.com/article.html?artnum=60939
>>
>> Which begs the question: how can you plug the iPod-to-USB cable into either a
>> computer (which outputs 5vdc) and the USB AC adapter (which outputs 12vdc)
>> and have no problems?
>>
>> I must have some incorrect information... ?
>
> Yes you do. USB is 5 vdc.


The back of my 2nd Gen. Nano says "5-30V 1A max."

PhattyMo wrote:
> Meat Plow wrote:
>> On Wed, 20 Dec 2006 02:00:39 -0800, John E. Has Frothed:
>>
>>>> the iPod has accommodation on its connector for both FireWire power
>>>> (12vdc) and USB power (5vdc).
>>> Hmm... according to this paper, both the USB and FW supplies output
>>> 12vdc:
>>>
>>> http://docs.info.apple.com/article.html?artnum=60939
>>>
>>> Which begs the question: how can you plug the iPod-to-USB cable into
>>> either a computer (which outputs 5vdc) and the USB AC adapter (which
>>> outputs 12vdc) and have no problems?
>>> I must have some incorrect information... ?
>>
>> Yes you do. USB is 5 vdc.
>
>
> The back of my 2nd Gen. Nano says "5-30V 1A max."


By the way,Does anyone know how to get a 2nd Gen. Nano to charge from a
USB port *without* a host controller?
(IE,just +5V and GND connected to a USB jack.)
I tried the pull-up/pull-down resistor thing on the Data+ and Data-
lines,Nada.Leave them floating,Nada.
It charges for ~3 seconds,then stops once it discovers that there's no
host to negotiate with.

I wonder if it needs to negotiate with the host over the Firewire
connection also? Wish I had the firewire cable to try it!