Ahhh so this is why you get “Charging is not supported”

Seems that everything Audio has an iPod charger on it these days which is great. However every time I upgrade my iPhone/iPod Touch I find yet more of them don’t work any more, with a “Charging is not supported with this accessory”.

So Via BoingBoing I found this seriously geeky explanation of how Apple Devices decide what charger they are connected to and what they can do with it quite enlightening.

Basically the charger tells the iPhone/iWhatever device what current it can draw (0.5 Amp or 1 Amp it seems) by putting a voltage on the data line, which the iPhone senses. So when older chargers don’t put this voltage on the line, that’s why you get charging not supported….