Canon PIXMA MP620 Series Getting Started page 26

When the Setup Completion dialog box appears, remove the USB cable,
then click Next.
Turn off the machine, then place the machine in the location where you
will use it, and turn on it.
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USB
To change the port name, click View Setup Results, then click Set Port Name.
For details, refer to "8 Changing the port name" in the printed manual:
Network Setup Troubleshooting.
If Unsafe Removal of Device is displayed, click OK.