I'm working to use a TA904 as an ATA on my Asterisk box. I have the the FXS Port registered as an extension, and it mostly seems to work ok, but when a Handset make a call, the handset never hears the 'ringing' of the phone. So you don't know if a call is progressing until the remote party answers. Once they answer, 2way audio is fine. I'm thinking it's something simple. Here are the relevant parts of my configuration. Hopefully someone can point out my error. Is there anything more than this needed for an ATA setup?