How to make a usb device recognize a device

If enough current is provided through the cable at the correct voltage, the ipod will charge.

What you observed is, I think, the computer cannot recognise the ipod and find a driver for it.

It does not have anything to do with charging.

Device can still be charged on USB port if they are not recognised.

Check your ipod's battery indicator to verify that the battery is indeed charging.

If it is not, then there is some hardware problem with the USB port or the ipod.