An isolinear rod was a type of information storage technology used by the Cardassian Union.
Quark used isolinear rods to gain access to the various Cardassian systems on Deep Space 9. Different colored rods, which included crimson, jade, topaz and sapphire, had different chances of being detected. (DS9 episode: "Babel", DS9 novel: The 34th Rule, DS9 - Mission Gamma novel: Twilight, DS9 novel: Warpath)
- DS9 episode: "The Forsaken"
- DS9 episode: "The Homecoming"
- DS9 episode: "Shadowplay"
- DS9 episode: "Improbable Cause"
- DS9 video game: The Fallen