If you can stand for a few minute delay, you can set up a voice mail box and turn on outcall notification. This will allow you to tell the caller to leave name and number and someone will call back within 5-10 minutes. We have done the Dest/Route programming to route to a cell phone. In one case it worked great over PRI, in the second case the cell phone users could not talk to the caller. Go figure. DB loss is the norm. If you have lousy lines coming in, you double it coming in and going out.