IS the echo only on station to station calls or on co line calls to thru the system? Most of the time echo is a result of utilizing copper phone lines on a system with an IP phone. If you are having the problem boost open your codec (G711) and test. What are the IP phone users using for there service? DSL, cable? I'm still learning as well and am a novice. I just keep telling the sales force that VOIP is not audio quality of copper or T-1/PRI lines, not yet. Hope some of this helps!