we seem to have lost nbc s katy tur on the phone there for us. reporter: hey, craig, craig, craig. we have you back. i have you. thank you. keep going. reporter: i m sorry. one more time. so the pulse from the black box, 37.5 kilohertz, gives off that frequency because nothing else in the ocean sounds quite like that and why the chinese hopeful it could be it. a lot of skepticism of experts saying the chinese don t have the technology to find that. that s why hms echo rushed to the scene. also ocean shield, that is an australian ship going there, as well, but the first it heard its own awe kousic technology.