Numbers that can be pressed when the Mobile Phone is locked

Today, when I was so boring that I took out my cell phone and dialed some strange numbers, such as 12345678900, 13400000000, etc, which are all empty numbers. Just for a while, I have not pressed any button, the keyboard got locked. Before I unlocked it, I pressed 1, then it appeared on the screen. I was so strange that I tried all the other keys. I found just 0,1 and 9 could be shown on the screen when the phone is locked. 0,1,9...0,1,9...what number can I get from these three numbers? Yeah, 911, 110, 119, er... just these. Then I tried those out, however, just 911 could effect, that means when the phone is locked, you can alse press number 911, then on the left corner of the screen, there comes out a function "call", yes, you can dial it out!