Echo problem on SIP server

I have SIP server with astersik software installed on fedora Core4, and im using CISCO 7940&7905, and am using POE 48V, every thing is working fine except there is a problem that i hear echo sound, is there any sugestions to solve this problem.

Many thanx in advance

Echo is one of the most common problems in packet switched networks. It can have a variety of causes.

Always keep this in mind:
If you are on extension “A”, calling to “B” and you hear your own voice,
Then the problem is at the “B” end ! After all, it is the “B” extension that reflects your voice back on the line.
Check whether you can enable echo suppression on your “B” end extension.

Happy hunting …unting…ing…


thank u for ur reply, but i have allready done that, for echo suppression on end user extensions, i read this article about echo cancller may solve the problem

I have another problem with my server, that from time 2 time memery and all its process crash even i cannt get in to the system till i reboot the server then every thing went ok, i think there is a process that crash my system, plz help…