If you forgot the IP address that is assigned to the switcher, the C200 will display it's ip address during boot.

You can temporarily set the IP address back to the default IP address of by holding down the config button (button one on the preview row) and button 1 on the program row at the same time then apply power to the device.  This will boot the switcher into configuration mode using the factory default IP address.  If you do not change the IP address in configuration mode, net time you reboot the device it will return to the previous IP address.

The default IP address is put back in permanently if you do a factory reset.  For details on how to perform a factory reset visit the How Do I Perform A Factory Refresh? article.