We have an audiocodes mp118 fxo, and we have a problem, when someone from the outside world, coming into our fxo, goes to someones voicemail, when they are done recording and hang up, but not press # , the audiocodes fxo doesn't detect they have hung up, and it keeps the phone line tied up for a period of time. Then the voice mail has a blank recording after the message for a period of time. We have a grandstream fxo, and it has no problem detecting when the customer hangs up after a voice mail. Audio codes tech support has been unable to help us with this issue. Anyone have any ideas?