(original series) Star Trek episode: The Menagerie
At some point prior to “The Menagerie”,[7] Pike is promoted to fleet captain. He is severely injured while rescuing several cadets from a baffle plate rupture on board a J-class training vessel, the delta ray radiation leaving him paralyzed, mute, badly scarred, and dependent on a brainwave-operated wheelchair. His only means of communicating is through a light on the chair: one flash meaning “yes” and two flashes indicating “no”.
https://en.wikipedia.org/wiki/Christopher_Pike_(Star_Trek)#The_Menagerie
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“The Menagerie” is a two-part episode of the American science fiction television series, Star Trek. It consists of episodes 11 and 12 (production #16) of the show’s first season and is the only two-part story in the original series. Part one of the episode was broadcast on November 17, 1966, with part two broadcast on November 24, 1966.
https://en.wikipedia.org/wiki/The_Menagerie_(Star_Trek:_The_Original_Series)
"Two Beeps. Yes, Yes."