I have several users that are using phones over asa phone proxy (ASA v8.2) and when they make calls from their phone to phones that are not on the proxy, two way audio is established. If a phone proxy user calls the phone of another phone proxy user, the call results in one way audio from the originating caller. so on the originating side, the user cannot hear the called party and also the originating caller has no recvr packets.
any ideas? i've triple checked the MTP config on the ASA phone proxy and it looks fine.