The phone number just made me dig, because I forgot what it was.
One of the resulting pages was an article that mentions "Though the "red telephone" seems to have become obsolete, it frequently pops up in fiction and political propaganda — Hillary Clinton's 3 a.m. phone call ad"
https://theweek.com/articles/496043/who-answers-white-house-phone-anyway
So here's that ad https://www.youtube.com/watch?v=7yr7odFUARg