To return your unit to its factory settings and reset the password:
Connect a serial terminal to your unit's console port using the settings given on the back panel label.
Reboot the unit and watch the output on the serial terminal. After a few seconds you will see the message 'Cisco TelePresence MCU 8510 4.2(0.36) (Build 6.17(0.36)) starting' or similar.
Type reset_config and press Enter. (Type reset_password and press Enter if using an IP Gateway. Note this command can be used at any point, not just when the unit is rebooting, and no settings except the admin password details will be restored.)
Type yes or y and press Enter. The unit will now reboot again.
When bootup is complete, type status on the serial terminal to see the IP address that the unit has acquired using DHCP. Alternatively, set a static IP address on port A using the static command.
Connect to the web interface of the unit and log in using 'admin' and no password. A warning message on the web page banner will tell you that a product activation key is required.
Go to Settings > Upgrade and enter the unit's activation keys. After the activation keys are applied, you will be able to use your unit again.
记得先保存license key