[asterisk-users] Asterisk 1.6 vs 1.4?

[Tzafrir Cohen]

On Thu, Jun 05, 2008 at 09:28:52PM +1000, Rob Hillis wrote:
> 
> 
> Tzafrir Cohen wrote:
> > On Thu, Jun 05, 2008 at 03:40:14AM +1000, Rob Hillis wrote:
> >   
> >>> If you use a hardware EC (or technically: a span-specific echo
> >>> cancellation method) the generic Zaptel echo canceller (software-based,
> >>> OSLEC in this case) will not be used.
> >>>       
> >> That's not always been my experience with OSLEC.  HPEC and the generic 
> >> Zaptel echo canceller seem to work this way, but as I've said, I've had 
> >> two cases where I've had to remove OSLEC to stop it degrading voice 
> >> quality where there is a hardware echo canceller in play.
> >>     
> > Unless there are some really strange OSLEC patches floating around, of
> > which I'm not aware, this should not be the case.
> >
> > OSLEC uses exactly the same EC interface to Asterisk as the built-in
> > one and HPEC do. Any chance you didn't actually fully unload zaptel?
> >   
> 
> These weren't installs that we'd done - in both instances, they were 
> companies who had bought Trixbox based systems from someone else who had 
> subsequently gone out of business.  Granted, I had /assumed/ that OSLEC 
> was causing problems by not disabling itself properly when hardware echo 
> cancellation was found - and I guess that assumption stuck when the 
> removal of OSLEC resolved the problem.

Trixbox has (had?) an earlier version of OSLEC that failed to properly
handle the echo training function. And it also sets echotraining=800
(which is probably is not such a good idea anyway nowadays).

That combination causes bad audio. Disable echo traning and/or upgrade
OSLEC.

-- 
               Tzafrir Cohen
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