Ring back is sent from trm end to org end. Does call ever connect and do you get 2way voice? If the answer is yes, then most likely your org device is not set correctly and needs to open the media path on ringing. If you do not get voice in both directions, then you need to look at the config of your CR and test direct to the end device to see if there is port blocking.
MikeM
mike_voip@hotmail.com