Why can't I charg Iphone through iMac Keyboard USB

[JRH147]

Finally got down to reading the User Guide (I bought my first iPhone on Friday) and I noticed that in the manual it says do not charge the iPhone through the USB Keyboard (I have an iMac from Oct. 2007).

I've charged it twice through there with no problem. In fact, my phone battery was low last night so I plugged it in, left it in over night and came back in the morning and it was fully charged. The manual says that if you charge it to a computer that is asleep or standby (which mine was- i always hit the button on the back at night) that the battery will drain - but it didn't.

What the heck is going on here?! Thanks for any help.

 

[Macjames]

I believe that the iMacs usb port on the keyboard is much more lower powered than on the back of the iMac, you can charge from it sometimes as you found out, but it is not ideal.

 

[Tankgunk]

The above is correct. The USB ports on your computer supply much more power to devices than the low power ports on your keyboard. You might be able to get a charge that way, but you risk improperly charging (or even damaging) your iPhone.

 

[nick9191]

The USB port on the keyboard is USB 1.1, the USB port on the iMac is USB 2.0.

 

[Tankgunk]

The USB port on the keyboard is USB 1.1, the USB port on the iMac is USB 2.0.

The USB version has to do with speed, not power. The USB ports on the keyboard are low power simply because the keyboard doesn't have a power supply aside from what it gets from the computer's USB.

 

[OllyW]

The USB port on the keyboard is USB 1.1, the USB port on the iMac is USB 2.0.

That isn't quite true. The older white keyboard only had USB 1.1 ports but the newer aluminium keyboard is equipped with USB 2.0 ports.

 

[JRH147]

How could I damage my iphone by charging it with a low-power port? I'll be really upset if I somehow screwed it up and I've only had it for 3 days!

I'll charge from now on through the computer USB ports but would like to know how it could be damaged?

 

[batfink]

How could I damage my iphone by charging it with a low-power port? I'll be really upset if I somehow screwed it up and I've only had it for 3 days!

I'll charge from now on through the computer USB ports but would like to know how it could be damaged?

well if you have the keyboard in the picture above then it really isn't a problem anyway.