[asterisk-users] Customer complains of noise on line I cannot reproduce.

[Steve Totaro]

He said in the OP that he is using a Digium TDM400.  I guess turning
EC off could help diagnose that pretty quickly.

I have diagnosed this issue (when it was hardware failure) by creating
different dialout extensions in the dialplan, to hit zap/1, then zap/2
etc.

Then I found it was only on zap/4 so I shuffled the modules.  One time
the problem moved to zap/1 so it was a module, another time the
problem stayed on zap/4 so it was the port on the card itself.

Thanks,
Steve Totaro

On Wed, Feb 27, 2008 at 4:57 PM, Eric Wieling <eric at fnords.org> wrote:
> Could this be ECFO?
>
>  Echo Canceler Freak Out, this happens when the rxgain is too high and
>  the echo canceler freaks out.  Some users describe it as "screeching",
>  "feedback", "static", or other useless terms.  If users report "static"
>  on a system where there cannot be static (all digital, PRI, SIP, etc),
>  you might be experiencing ECFO.
>
>  Try lowering your rxgain and txgain.
>
>
>
>  Fons van der Beek wrote:
>  > Perhaps irq sharing?
>  >
>  > Royce Souther schreef:
>  >> I have setup a few Asterisk systems for customers using Digium TDM400
>  >> cards and Aastra phones. No problems with sound quality at all except
>  >> at this one site.
>  >>
>  >> Every time I try their system I don't hear any problems but they tell
>  >> me that it is really bad. They describe it a a loud scratching sound.
>  >>
>  >> Are there any tests that can be done to pinpoint the problem? Has
>  >> anyone seen this before? Are there known causes for this?
>  >>
>  >> --
>  >> Open Source: To innovate then create
>  >> Proprietary: To imitate then litigate
>  >> ------------------------------------------------------------------------
>  >>
>  >
>
>  --
>  Consulting for Asterisk, Polycom, Sangoma, Digium, Cisco, LAN, WAN, QoS,
>  T-1, PRI, Frame Relay, Linux, and network design.  Based near
>  Birmingham, AL.  Now accepting clients worldwide.