Dennis Webb wrote:
This seems to be how AGGRESSIVE_SUPPRESSOR works. To make sure you don't get echo, it does what a speakerphone does, mute the other party if it hears audio from your end. There is a setting in mec2_const.h for AGGRESSIVE_HCNTR=160 that says in the comments 20ms, I'm assuming this is to tell how long to suppress the other party. There is nothing on this that I have found anywhere and since we are live, I can't change until later to see how it works.
We have Polycom SIPS for users, and it doesn't matter what the other party is. It seems from another thread, that the problem midcall is that the electrical properties of the line change midcall causing the echo to return. Without AGGRESSIVE_SUPPRESSOR defined the first minute or so is fine, then a click happens and the echo begins. The phones also seem to go extra sensitive then. You can then hear even keyboard clicks from typing where you don't normally. I've wondered if it's the zaptel cards or poor electricity at my place to the asterisk server. I have put in a SmartUPS 1500 to try to condition electricity there just to make sure.
The problem mid call is due to a bug in the wctdm driver. It slips frames. When that happens, the echo canceller's training is completely wrong, and the echo comes back. It might even be rather worse than with no canceller at all. This is the same problem which prevents the TDM cards working reliably with FAX machines. I don't know if action is being taken to fix this.
As far as echo and PRI, thanks for making me cry since I just knew that would solve it.
Well, it better than buying more stuff, and being disappointed. :-)
Regards, Steve
_______________________________________________ Asterisk-Users mailing list [email protected] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
