A lighting device 12 includes at least one point light source 17, an optical member 15a provided on a light output side of the lighting device 12 from the point light source 17. The mobile phone includes a control circuit and a volume detector. This optical carrier is then electro-optically modulated with an RF frequency chirp, creating an optical chirp probe beam with a frequency chirped optical spectrum having upper and lower frequency chirped sidebands that have amplitudes sufficient to be detected at a detector. A second crew and a second sequence associated with the second leg of the at least two broken legs is identified.