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

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

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

Hi!

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.

You should be *extremely* careful if you do this. The voltage provided on
the Firewire bus is 48 volts! USB only puts out 5 volts. The difference
would likely cause immediate destruction of the USB circuitry or even the
whole iPod.

I have an Apple-made Firewire-style charger for an iPod. I believe it puts
out 48 volts as well, but I'll have to check.

William

In article y2oih.322661$1i1.178242@attbi_s72,
William R. Walsh m
wrote:
You should be *extremely* careful if you do this. The voltage provided on
the Firewire bus is 48 volts! USB only puts out 5 volts. The difference
would likely cause immediate destruction of the USB circuitry or even the
whole iPod.

Why 48 volts? Seems strange to use a non native voltage.

--
*Sleep with a photographer and watch things develop

Dave Plowman London SW
To e-mail, change noise into sound.

On Thu, 21 Dec 2006 04:27:10 GMT "William R. Walsh"
m wrote in Message id:
y2oih.322661$1i1.178242@attbi_s72:

You should be *extremely* careful if you do this. The voltage provided on
the Firewire bus is 48 volts!

Huh?

http://www.interfacebus.com/Design_C..._Firewire.html

30 volts.

I thought the spec is something like 9v-40v.. I'm pretty sure the 1394 ports
on my computer are 12v. I made a car charger for my old firewire ipod with a
firewire cable and a cigaret lighter plug. I havn't had any problems.

- Mike


"Meat Plow" wrote in message
news
On Thu, 21 Dec 2006 10:06:40 +0000, Dave Plowman (News) Has Frothed:

In article y2oih.322661$1i1.178242@attbi_s72,
William R. Walsh m
wrote:
You should be *extremely* careful if you do this. The voltage provided
on
the Firewire bus is 48 volts! USB only puts out 5 volts. The difference
would likely cause immediate destruction of the USB circuitry or even
the
whole iPod.

Why 48 volts? Seems strange to use a non native voltage.

Full spec firewire can deliver 40 volts at 1500mh. Never heard of it being
higher than 40.

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

COOSN-266-06-25794

In article ,
JW wrote:
You should be *extremely* careful if you do this. The voltage provided
on the Firewire bus is 48 volts!

Huh?

http://www.interfacebus.com/Design_C..._Firewire.html

30 volts.

Well that's three 'specs' so far. ;-)

But why the non native voltage? Only reason I can think of is long cable
runs - but then why power such a device off the cable?

Incidentally I've got a FireWire PCI card on my PC and there's no sign of
a voltage convertor on it. It does have a 5/12volt input as well as the
edge connector, though.

--
*Whatever kind of look you were going for, you missed.

Dave Plowman London SW
To e-mail, change noise into sound.

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!

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!

IIRC the Nano does not support FireWire as the earlier iPods did.

Well I know that the newer ipods don't support firewire, but they will still
charge from it.

- Mike

"James Sweet" wrote in message
news:1uFmh.3083$T%3.1644@trndny08...


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!

IIRC the Nano does not support FireWire as the earlier iPods did.