How to hard reset ZyXEL Prestige 660H-D1
In order to factory reset your ZyXEL Prestige 660H-D1:
1. Power on your device.
2. Locate the Reset pinhole on the bottom of the unit.
3. Press with a paperclip or a sharp object for at least 5 seconds.
The default factory settings are:
Default IP address: 192.168.1.1
Default username: blank
Default password: 1234