It's a reference to this scene from Star Trek IV: The Voyage Home (1986).
Explanation without video
Scotty, having traveled back in time to the year 1986 as part of a mission to rescue some whales, attempts to use a computer by speaking to it and then mistakenly tries to use the mouse as a microphone when the machine does not respond. He is prompted to use the keyboard instead of verbal commands and gives information on how to manufacture transparent aluminum. This material was not invented until about 150 years later according to the pre-trip history of the Star Trek future but Scotty has given it a head start.