[Asterisk-Users] Static and echo on PRI

[Matt Klein]

ask your upstream.....

On Wed, 27 Apr 2005, Mark Johnson wrote:

> Andrew Kohlsmith wrote:
>
>> Try these things:
>> 
>> Software:
>> - don't play with gains on PRI or T1 unless you have echo or too 
>> loud/quiet.  Static isn't caused by screwy gains and on digital circuits it 
>> technically shouldn't ever need to be adjusted
>> - turn echocancel off for now
>> - I notice you've got span=1,0,0 -- if you're talking to the telco make 
>> sure you're synchronizing the clock to them.  Use span=1,1,0.
>> - remove all modules except those absolutely necessary
>> - Have you tried span 2, 3 or 4 instead of 1?
>> 
>> Also is this a *stock* kernel or some distro-"enhanced" version?  Grab a 
>> stock kernel of the same version from ftp.kernel.org.
>> 
>> Finally, don't use the agressive canceller unless you REALLY can't get rid 
>> of it any other way (I seem to have very good performance with MARK2, using 
>> the MMX-friendly implementation (zconfig.h) and making sure my CFLAGS for 
>> the zaptel code was optimized for my processor (-march=pentium4).
>> 
>> Also see 
>> http://lists.digium.com/pipermail/asterisk-users/2004-November/071301.html.
>> 
>> Hardware:
>> - *remove* the TDM22P from the system.  Don't just unload the modules.
>> - pull the TE405P out and put it in another (not same motherboard) system. 
>> I've seen this clean things up several times.
>> 
>> Wetware:
>> It's getting a little late for this now, but you paid for support from 
>> Digium when you bought the card; You might want to give them a call. 
>> Unfortunately I don't think this is an issue they will be able to solve 
>> over the phone, and their likely recommendation would be to replace the 
>> system.  I'd love to know what they do find, if you try this route.
>> 
>> Again, my apologies, for blasting you; I had you mixed up with someone 
>> else.
>> 
>> -A.
>> 
> This is perfect stuff!!!  Thank you!!  I actually pulled the TDM22P today, 
> removed all of those drivers and get the same results.  I have built another 
> box and am installing asterisk as we speak.  I tried the span=1,1,0 with the 
> same results and have been running that line for a day now.  What I find 
> strange is this...  If I speak at a normal tone, it sounds OK.  I still get 
> static noise when the other person speaks.  If I talk louder, I start to get 
> what sounds like a partial echo.  If I yell, I get a definite echo.
>
> Have not tried a different slot on the quad, will try that tomorrow.
>
> When monkeying with the echo cancel, I never really noticed a difference.  I 
> would even reboot the machine between changes to see if it made a difference.
>
> I am running this on Fedora Core 1.  I will try any OS you recommend, but I 
> have always had great luck with RH type distro's.  I keep 400 and 500 day 
> uptimes on those machines and they run many, many services.  Uptimes would be 
> higher but it seems whenever I find a good place to work, they close up or I 
> move.  Admittedly, I don't use RPM's for the core services, I typically 
> compile those myself.  I also shut down every module and service I don't 
> need.  I did alot of reading and it seemed like Digium cards were the real 
> deal and I also found many users that had luck with the same setup.  Should I 
> try a different approach/OS/system?
>
> Mark
>
>
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