A search-and-rescue effort has two phases, says M.J. Lewandowski, the research center project manager. The first is the notification phase, in which the distressed sailor lets it be known that the vessel requires assistance. This can be done with pyrotechnics or other visual devices, but usually occurs through the use of an EPIRB, DSC emergency-calling-equipped radio, a VHF voice call, or cellphone or satellite phone. The second phase, locating the boat, is where the ability to use a good signaling device is paramount. As potential devices are analyzed by the Coast Guard, some of the criteria examined include light-signal characteristic, intensity, color, ease of use, duration of use, range in different conditions and the overall effectiveness of present technologies.