The Mode button will reset all the configuration of the device. Please find the details below:
Resetting the Switch
Why you might want to reset the switch:
1. You installed the switch in your network and cannot connect to it because you assigned the wrong IP address.
2. You want to clear all configuration from the switch and assign a new IP address.
3. You are trying to enter Express Setup mode, and the switch LEDs start blinking when you press the Mode button, which means that the switch is already configured with IP information.
Caution Resetting the switch deletes the configuration and reboots the switch.
To reset the switch, press and hold the Mode button. The switch LEDs begin blinking after about 3 seconds. Continue holding down the Mode button. The LEDs stop blinking after 7 more seconds, and then the switch reboots.
The switch now behaves like an unconfigured switch. You can enter the switch IP information by using Express Setup as described in the "Running Express Setup" section.
Hope this help.