Quindar tones, most often referred to as the "beeps" that were heard during the American Apollo space missions, were a means by which remote transmitters on Earth were turned on and off so that the Capsule communicator (CapCom) could communicate with the crews of the spacecraft. It was a means of in-band signaling to simulate the action of the push to talk-release to listen (commonly referred to as PTT) button commonly found on walkie-talkies.
Read more about Quindar Tones: The Need For Quindar Tones, Implementation of Quindar Tones, Common Misconceptions About Quindar Tones, Origin of The Name
Famous quotes containing the word tones:
“There sighs, lamentations and loud wailings resounded through the starless air, so that at first it made me weep; strange tongues, horrible language, words of pain, tones of anger, voices loud and hoarse, and with these the sound of hands, made a tumult which is whirling through that air forever dark, as sand eddies in a whirlwind.”
—Dante Alighieri (1265–1321)