Quindar sounds were used by nasa for controlling the ground station transmitters that allowed communication with spaceships through the space shuttle era. Fiber optic cable has made quindar sounds obsolete. This sound, at 2525 hz, was generated when the capsule communicator pressed the ptt button on his microphone, and the pitch told the ground station transmitters to start broadcasting. You can read more about quindar sounds at https://www. Hq. Nasa. Gov/alsj/quindar. Html. This sound was generated in audacity.
Author: Lilithvf