- You may also be looking for Code One alert, the Starfleet signal that denotes the declaration of war.
In the late 23rd century, the Code Factor 1 designation on a message meant that it concerned an invasion of the United Federation of Planets. Such messages were of extraordinary importance. In 2267, the galaxy wide "winking out" effect caused by Lazarus and Anti-Lazarus as they transited the negative magnetic corridor was at first believed to be the prelude to an invasion. Commodore Barstow issued a Code Factor 1 message regarding this phenomenon, and ordered the USS Enterprise to investigate. (TOS: "The Alternative Factor")