I work with Linux off and on. While I am not what you would call expert I can handle it. I go way back with OSs like DOS, VMS and others. If I can download the Asterisk system I can load it on a virtual machine here. If I cannot handle it I will pass it on but at least I can get a little something for perhaps fixing the existing issues.

But please, where would one begin to troubleshoot this? Is it a software issue or is it just a bad handset? The problem is reported as intermittent. They have Aastra phones, models 6755i and 6731i.

The main problem is excessive echo on some calls. My first hunch is they have Dlink switches bought from Costco and have their phone network on the same LAN as their classrooms with 50 students accessing the Internert at the same time.