[Asterisk-Users] echo cancellation: the never-ending quest fortruth

[Robert Rozman]

Hi,

is there any list of problematic motherboards ?

How does Asus P4P800 behave in this manner or Asus boards in general ?


Regards,

Robert.

----- Original Message ----- 
From: "Rich Adamson" <radamson at routers.com>
To: "Asterisk Users Mailing List - Non-Commercial Discussion"
<asterisk-users at lists.digium.com>
Sent: Tuesday, October 05, 2004 10:17 AM
Subject: Re: [Asterisk-Users] echo cancellation: the never-ending quest
fortruth


>
> > Asterisk apparently has five echo cancellation algorithms: STEVE,
STEVE2,
> > MARK, MARK2 and MARK3.  The current default appears to be MARK2.
> >
> > My question is, has anyone had any experience with any of the others
> > (other than MARK2), and is there some conventional wisdom as to when to
> > use one over another?
>
> Most of those were variations that attempted to address echo issues with
> the old x100p card. If you look at the source code dates, none of those
> have really been touched in well over a year.
>
> According to Steve, the echo cancellation algorithms do not have a very
> wide operational range, and as a result its not all that difficult to find
pstn
> situations were the echo characteristics fall outside the usable ranges.
> Its basically a trial & error test to see which one works the best given
> "your" pstn line characteristics. Your neighbors line characteristics
> may be completely different.
>
> Following Mark's echotraining=800 changes around June 2004, it seems
> most echo problems were minimized, and there hasn't been any list
> activity relative to those algorithms since then.  Those that still had
> objectionable echo found that swapping motherboards cured their issues.
> That seemed to be related to interrupt latency and/or pci bus controller
> chip problems that are apparently well known to those that work heavily
> with audio applications.
>
> Rich
>
>
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