In text mode, press the left Alt-F1 to Alt-F12 to select the consoles tty1 to tty12; Right Alt-F1 gives tty13 and so on.

 

To switch out of X you must press Ctrl-Alt-F1, etc; Alt-F5 or whatever will switch back.

 

However, If you have a non-PC compatible system, please see the note below.

 

If you want to use a VC for ordinary login, it must be listed in /etc/inittab, which controls which terminals and virtual consoles have login prompts. The X Window System needs at least one free VC in order to start.