Mio c320 - Manual (Page 14)

1.3 Charging the Battery via the USB Cable
1. Turn on the computer.
2. Connect the mini-USB end of the USB cable to the bottom of your device and
the other end to a USB port on your computer.
3. If your device is on, the screen as shown below appears. Whenever your
device is connected to a computer, you will not be able to use it.
4. The charge indicator glows amber when charging is in progress. Do not
disconnect your device from AC power until the battery is fully charged, the
charge indicator will turn green. This will take a couple of hours.
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