Subspace signal

A subspace signal or subspace radio signal was a quick signal through subspace to attempt to initiate communication or to check for responsiveness.

In 2369, Odo and Croden were in the USS Ganges when a subspace signal came in on the Vulcan band frequency. It was a communication from the captain of the T'Vran asking if the runabout needed assistance. (DS9: "Vortex")

Later that year, Benjamin Sisko proposed using a class-2 probe to investigate a narrow band subspace signal emanating from a moon in the Gamma Quadrant. (DS9: "Battle Lines")

In 2371, Miles O'Brien attempted to contact the planet from the USS Defiant by aiming a subspace signal at one of Earth's satellites, although they had been erased from time by the death of Gabriel Bell in 2024. (DS9: "Past Tense, Part I")