When Mance gives the SIGNAL
and we hit Castle Black,
Game of Thrones Season 3, Episode 7
The point of a secret knock
is to establish a nonverbal SIGNAL...
The Big Bang Theory Season 1, Episode 16
No SIGNAL, no plan.
Game of Thrones Season 2, Episode 9
The radio SIGNAL indicated
they were moving. They're around here.
Money Heist Season 3, Episode 7
-perhaps we could come up with a SIGNAL!
The Big Bang Theory Season 10, Episode 16