I am not sure this is what you are asking. But I guess you want to alternate between the text console and X.
For this you need to use control+alt+f<n>, being n a number from 1 to 12 usually. Most distros start X on vt7, and the first text console in vt1, so using control+alt+f1 will get you to the first free vt, and control+alt+f7 will take you back to the X graphical environment. However it could be a different number for both, it just depends on your configuration, the number of graphical sessions you have open, etc.