[Asterisk-Users] how do i get rid of this blasted echo !!!

[Andrew Kohlsmith]

On March 3, 2005 07:02 am, Brett, Gary wrote:
> I have 2 TDM400P's, 2 asterisk servers (running on powerful boxes with FC1
> and * v CVS 1.0.02), and 4 analogue PSTN lines from BT and whatever I do, I
> cannot get rid of this damn local echo. Ive tried setting the echoTraining,
> echoCancel (in phone.conf and Zapata.conf) , echocancelwhenbridged to every
> possible combination , Ive even tried running the fxotune utility to no
> avail. Ive swapped cards, telephone lines, servers and also tried different
> phones (budgetone, x-lite, 7940) but still it's the same.

You haven't told us what hardware (platform) you're on, nor have you told us 
if your FXO ports are in whatever mode they need to be in for UK impedances 
(I think they default to FCC or North American).

For echo on my PRI I could not get rid of it until I recompiled the zaptel and 
wct4xxp drivers with MMX support enabled and with the instructions reordered 
and used for the pentium 4 processor (which I'm using, Xeon 2.6 to be exact).

After that, the echo magically disappeared.  I haven't reverted back to my 
original (non-processor-optimized, non-MMX-enabled) drivers to see if it 
comes back, but that's all that's changed and it's in production so I am 
hesitant to screw around with it any more.  

-A.