[Asterisk-Users] EADS6550 and asterisk - echo on PSTN call

[Rich Adamson]

> >>would like to know if some of you have tested asterisk connected to an 
> >>EADS 6550 analogique PBX (also know as Nexpan50).
> >>
> >>Our set up is a Dell Optiplex with 1 TDM400 4 FXO, 1 TDM400 4 FXS, (no 
> >>other card, each of them have their own IRQ) all ports connected to the 
> >>EADS. We have GS ATA286 as EP. Calling from ATA to ATA give a perfect 
> >>sound. Calling to PSTN numbers or reverse side, give echo.
> >>
> >>We can do what we want in zconfig.h (STEVE2, MARK2, MMX, 
> >>AGGRESSIV_SUPPRESSOR, NOECHOCAN_DISABLE) or zapata.conf (tx gain=-10.0, 
> >>echocancel=32 ... 256,), test with differents POTS phone, it change 
> >>nothing. We even didn't notice changes between our various changes in 
> >>those files (and yes modules where unloaded between each test). Always 
> >>the same echo.
> >>
> >>So know we start to doubt that this echo problem is asterisk related but 
> >>perhaps more to the PBX. That's why we ask if some of you have/had 
> >>similar setup with this PBX and if there is a solution.
> >>    
> >>
> >
> >You didn't mention what country your in; if you outside the US, be sure
> >to config the TDM-fxo card for your country (eg, line impedance).
> >  
> >
> France.
> 
> >You mention echocancel=32, etc, did you try echotraining=800?
> >  
> >
> Yes. It create a second echo :-(
> 
> >For my TDM-fxo in the US, using the following on each channel works fine:
> >
> >echotraining=800
> >echocancel=yes
> >echocancelwhenbridged=yes
> >rxgain=5.0
> >txgain=0.0
> >  
> >
> Do you have this setup with the standard zconfig.h (MARK2)?

I might have missed some of your earlier posts relative to this; just
catching up on over 500 emails from this list.

I've not had to configure a TDM for non-US support, but I know
for an absolute fact (based on 20 years of detailed telephony
engineering experience) that you have to config the TDM card for
line impedance, etc, for your country. If you've not done that,
start there. (Think that's an optional parameter when loading 
the drivers.)

I update asterisk from cvs-head about every two weeks or so, and
always stick with default values (including zconfig.h). So, yes
I'm using the default echo cancellation, etc.

There has not been very many changes associated the the zaptel
source code and the TDM-fxo drivers. Certainly not necessary to
use the latest cvs-head at all; anything from the last few months
should work.