The
user interfaces include user interfaces of the Console port, AUX port and VTY.
When the user enters the lock command, the system prompts to input a
password for the screen saver twice and if the passwords input twice are the
same, the current user interface is locked successfully. After that, if you
want to enter the system, you should press Enter first and input the
password when being prompted to. When you enter the password configured just
now, you can unlock the user interface and enter the system