Just an update to my progression with this problem. The V3000s that I got back from 3COM came in with 4.4.2 code, and I left them with 4.4.8 because it was late in the day and I hadn't got 5.x the license codes yet. This has been nagging at me, so I took one off the shelf that had 4.4.2 today and put it through the wringer checking for echo. It worked well until I upgraded it to 5.0.6, and I immediately got the echo. Problem is, when I went back to 4.4.2, the echo did not go away. If you watch the console screen while you're doing the upgrade to 5.x, it does a firmware update. I'm wondering if it's changing the charactaristics of the hardware somehow and causing this echo problem. I am opening a case on this box Monday morning, and I'll let you know what I find out. In the meantime, has anybody else seen anything similar?