The Lighthouse

Taken from a friend's journal:

A little backstory.  R is a somewhat goofy nerd.  He's a physics and math major (this is VERY important for this story).  We were at T's housewarming party when it was time to go.  T now lives in a gated community and she told us that the code was #1020 to get in.  So myself, J, A, R and B all get in my car.  I'm driving us out to drop A and R off at A's car and we get to the gate.  Apparently it was enter only and so we couldn't easily get out.  I tell R and A to hop out, go through the walk through gate and let us through.

Me: "Just press Pound Ten Twenty and we can get through!"
R: "Ok!" *runs to keypad* "...IT ONLY GOES TO NINE"
Me: "...........press pound one zero two zero"
R: ".....OK!"