[Asterisk-Users] Echo and crackle

[Mojo with Horan & Company, LLC]

I will agree that switching to the TDM card significantly helped my echo 
and sound quality, I would take a second to point out that interrupt 
sharing on your * server might cause crackling-like noises.  Try

lspci -vb
  and
cat /proc/interrupts

to see if you discern any hardware using the same irq the x101p is.

Also run zttest in the zaptel source directory and see what the average 
number is.  s/b 100%, but I believe as low as 98% or thereabouts should 
have pretty acceptable call quality.  If it dips even lower than that 
regularly, or concurrently with the crackling sounds, then your server 
is probably working too hard on irrelevant processes or has irq sharing 
issues.

Moj

M.Hockings wrote:
> We are running asterisk with a single POTS line for local calls and a 
> voip line for long distance.  Whenever we receive a call on the POTS 
> line it is more than likely, but not always, going to have significant 
> distracting echo.  In addition to that there is occasional heavy crackle 
> or static.  I have tried to follow the guidelines at :
> http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation
> but it does not seem to have made much difference.
> 
> Currently we are using a X101P for the POTS line and a TDM401B (TDM400P 
> with one FXS port) for the conventional telephones.  From what I have 
> read, it may help to use an FXO port on the TDM400P rather than the 
> X101P for the POTS line.
> 
> What is the "conventional wisdom" about the echo in this configuration 
> and what causes the crackle and how should I tackle that?  I have tried 
> rebooting/power-cycling the machine to reset the hardware but it really 
> hasn't noticeably helped.
> 
> Is there anything else that I can try?
> 
> Thanks,  Mike
> 
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-- 
Mojo <mojo at horanappraisals.com>
Office Manger, Horan & Company, LLC
(907) 747-6666 x112