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Generic AC USB chargers - Ipods and others

I've searched for this, but haven't found an explanation, and thought someone here might know.

There appears to be a difference in the dedicated (AC) charger requirements for Ipods versus other USB devices (other brands of players, phones, or what have you). Moreover, there appears to be a difference between generations of Ipods, such that some generic chargers will work with older Ipods, but not the latest generation, and vice versa.

Since I know it's true for my Sansa MP3 player, I'm gonna assume that other similar devices that charge through a normal USB port will also charge with a dedicated charger that provides 5VDC at a few hundred milliamps, and such a charger need not be "intelligent" at all. Do Ipods require something different? If so, what? And how does that vary from one generation to the next?

Ideally, there would be Apple documentation providing this info, but I haven't found it. If someone has a useful link on this, it would be most helpful.

Thanks

Reply to
George
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Ditto,I'd like to see it too.

With my 2nd gen Nano,it won't charge no matter what I do. There's a 'trick' to getting some of the others to work from a 'non-smart' charger that involves a couple resistors on the data lines,to either pull them high,or low. This didn't work on my iPod,I guess it needs an actual USB host controller to negotiate with? I dunno.

Reply to
PhattyMo

On further research, it may have something to do with this:

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That's a new standard for USB charging published in March,

2007. It now says that a dumb charger should have the data lines shorted together. Go figure.

So maybe the old and new ipods look for different things. And I guess it's also possible that ipods really want a formal connection to be established anyway.

I just wish I could find an authoritative explanation of what's required. I guess in time everything will comply with the new standard, but in the meantime it would be nice to know what the deal is for each ipod generation.

Reply to
George

Interesting. Thanks. I received an iPod nano (video) as a Christmas gift. (My first iPod, but not my first MP3 player.) Love it.

I was wondering what the charge current was (would be) if the device did not enumerate on the USB bus? For example, if I just wanted to re- charge the battery on a PC that did not have the iTunes software installed. I discovered that in that case, the iPod nano will just enumerate as an external hard drive, so I assume the 100mA "pre- enumeration" limit would not necessarily have to be imposed (since the device was enumerated)? That said, for all I know the charger function may never need more than 100mA anyway... But I was curious about that....

-mpm

Reply to
mpm

Not only that but an installed host application requirement soon to follow. And certainly M$ centric. The SPA, MPAA, and RIAA types cannot tolerate other than anal retentive copyright and DRM.

Reply to
JosephKK

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