The ringtone on his cell phone was the sounds of his native jungle, at night.
It was hardly audible to others and if they heard anything at all it was only white noise to them.
But to him it was as the mother hears the voice of a long dead child. The slightest whisper in the most boisterous crowd and she was alive, awake and every sense tingling, aware of every stimuli in the vicinity.
(Just a fragment, collected as with the sounds of the late summer night.)