In my case, when my towns fd gets a test, tone A and B go out, but not tone C. You see tone A and B will set off my pager, but tone C will set off the town siren, and open the bay doors. In most cases though, you will only need tone A and B.
Now for the siren that wistles at the end of the page: it is very difficult to make that siren, and has nothing to do with activating the pagers.....so no need to worry about that...