[Freeswitch-users] What is the difference between preAnswer and ring_ready?

Hi, Assuming an inbound call, I have trouble understanding what the supposed difference between the following two set of instructions is: session.execute("ring_ready"); session.set("set", "ringback=/home/ring.wav"); and session.preAnswer(); session.streamFile("/home/ring.wav") In practice, however, the first scenario doesn't work for me although the example here suggests otherwise: http://wiki.freeswitch.org/wiki/Misc._Dialplan_Tools_ring_ready Any idea? Thanks, Max.