asterisk users - Nov 2010 - "scratchy" sound on TE410P

asterisk 1.4.35
dahdi 2.3.0.1+2.3.0
one span on a 4port T1 card

Got complaints this morning that outbound and inbound calls were 
"scratchy" and I made a few test calls.  It kind of sounds like the
gain
is too high somewhere, and the audio is overdriven.  Is this a problem at 
the carrier?  I'm trying to call them now, but it's Sunday morning in
the
sticks, and my chances of getting someone with a clue are slim to none.

I restarted dahdi but that had no effect.

I watched dahdi_tool as calls came in and out but there isn't really a lot 
of information there.

Sangoma has a cool tool "wanpipemon" that shows error stats and such
on
the span.  Is there such a tool for Digium cards?

Any suggestions?

Thanks,

-- 

Jeff LaCoursiere
SunFone
jeff at sunfone.com

On 11/7/10 9:26 AM, Jeff LaCoursiere wrote:
>
> asterisk 1.4.35
> dahdi 2.3.0.1+2.3.0
> one span on a 4port T1 card
>
> Got complaints this morning that outbound and inbound calls were
> "scratchy" and I made a few test calls.  It kind of sounds like
the gain
> is too high somewhere, and the audio is overdriven.  Is this a problem at
> the carrier?  I'm trying to call them now, but it's Sunday morning
in the
> sticks, and my chances of getting someone with a clue are slim to none.
>
> I restarted dahdi but that had no effect.
>
> I watched dahdi_tool as calls came in and out but there isn't really a
lot
> of information there.
>
> Sangoma has a cool tool "wanpipemon" that shows error stats and
such on
> the span.  Is there such a tool for Digium cards?
>
> Any suggestions?
dahdi_maint -s <spanno> will provide the error counters that are 
available for the span.  i.e.:

]# ./dahdi_maint -s 1
Span 1:
 >FEC : 0:
 >CEC : 0:
 >CVC : 0:
 >EBC : 0:
 >BEC : 0:
 >PRBS: 0:
 >GES : 0:

You can see verify if the drivers are adjusting the gain on a channel 
with the dahdi_diag tool.  'make dahdi_diag' in dahdi_tools in order to 
build it, since it's not built by default.  Then:

']# dmesg -c > /dev/null  && ./dahdi_diag 1 && dmesg
-c'

And look for the gainalloc output to see if DAHDI is gaining the channels.

Cheers,
Shaun

-- 
Shaun Ruffell
Digium, Inc. | Linux Kernel Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: www.digium.com & www.asterisk.org

On Sun, Nov 07, 2010 at 10:26:59AM -0500, Jeff LaCoursiere
wrote:
> asterisk 1.4.35
> dahdi 2.3.0.1+2.3.0
> one span on a 4port T1 card
> 
> Got complaints this morning that outbound and inbound calls were 
> "scratchy" and I made a few test calls.  It kind of sounds like
the gain
> is too high somewhere, and the audio is overdriven. 
It could be the echo canceller, I had this kind of problem with OSLEC. I
also thought the PRI provider was sending clipped audio. I switched to
the VPM450 daughterboard and since audio has been crystal clear. What is
your setup for echo cancelling?

-- 

   Daniel Tryba