transmitting from a part of the aircraft. that's better than debris. debris, that doesn't mean there's a wreck. the wreck could be 1,000 miles away. >> the fact that it's a ping. everybody's talking about 37.5 kilohertz. >> kilohertz. >> does that mean something special to you? >> yes, it does because there's only one device that i know that emits that frequency and that's this emergency locater. now, if someone wants to mix that up with oceanographics and the song of the whale's call or the tortoise's mating call, they could give you thousands of them. but i'm hopeful this is the sound coming out of that flight data recorder. >> my previous guest told me with this ping from a black box -- and they manufacture the pinger -- that it continuously pings and that it gets a little weaker in frequency as time goes on. they only heard this for 90