dvdr that has the pingers attached to them, which one is which in order to locate this signal? >> well, they have to know what to be listening for. it's like trying to listen for extra terrestrial life. you have to know which direction to point your antenna. which frequency range to listen on. what the duration would be. whether or not what you're receiving is noise or is, in fact, what you're looking for. and the manufacturer as well as the installation and operation can no doubt tell you exactly how each of these was programmed. >> are they all 37.5? >> i believe it's programmable. >> okay. >> rob mccallum, you have a question for paul? or anything you want to add? >> i'd like him to comment, really, in that, you know, pingers are used widely in the deep water industry for