Code Factor 1
In the late 23rd century, the Code Factor 1 designation for a coded  message meant that it concerned an invasion of the United Federation of Planets. Such messages were of extraordinary importance. 

In 2267, the galaxy wide magnetic effect caused by Lazarus and  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  to investigate. ()

Communications technology