[Asterisk-Users] Static and echo on PRI

[Andrew Kohlsmith]

On April 26, 2005 10:28 pm, Mark Johnson wrote:
> Um...  If you read my orginal post, this was unplanned as I had a Cisco
> hardware failure.  I have been working on building Asterisk for over 6
> months and don't have the luxury of forking out over $5,000 for a test
> T1.  I also have noticed that in looking through this particular thread
> that I have never seen your name in it.  Just double checked the
> archives and, nope, you aren't there...

Who needs a test T1?  Two back-to-back TE110Ps work great for testing most 
aspects.

And I need to apologize; I have your posts mixed up with someone else's with 
similar problems and who didn't seem to follow up.

At any rate, I'm sorry.

> If you don't have any facts to share, please don't bother.  I am
> desperate and don't have alot of time left and am begging for the list's
> advice.  I left probably the largest post this month with EXACTLY what I
> have tried, the results, debug information, etc...  I have removed
> drivers, swapped cards, changed IRQ's...  I am open to any suggestions.
> If you tell me to go buy a different card, I will do that.  You guys
> know more about than I do.  What do you suggest, exactly?

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.