[Freeswitch-users] No Audio when dial out via gateway

Hi, I have successfully installed and configured the FS thanks to the community help. Greatly appreciate all. Now I have some basic error:   I can dial out from extension 1000 (all default ext) to any number not in the same network. I got the other number rung, and answered, but cannot hear anything from both ends. Strange thing is I can broadcast an audio into the conversation, and both ends can hear the audio, but just cannot talk.   I just hope that it would be something easy to be pointed out by experienced users.   Thank you,   Will