Have 2 FXO cards inserted with Cisco 1760. The problem is on the IP Phone side when no one is talking there is dead space. That is with vad turned off and Noise Regeneration enabled or disabled. Also when the client is talking on the IP Phone side there is no echo back while he is talking. Only time there is echo back is when the PSTN side is talking. Soon as the PSTN side stops talking there is dead space until PSTN side starts talking again. Any suggestions Thanks