[Asterisk-Users] Echo on a PRI

[Troy Settle]

On the subject of echo on a PRI, I too get this, but only when calling
people in certain rate centers.  Calls within my LATA (primarily VZ) are
completely free of echo.  Calls to a neighboring LATA (all Sprint) have echo
on almost every rate center.

I wish I knew more about this so I could rip Sprint a new one and tell them
to fix their trunking, but...

--
  Troy Settle
  Pulaski Networks
  http://www.psknet.com
  866.477.5638
 

> -----Original Message-----
> From: asterisk-users-admin at lists.digium.com 
> [mailto:asterisk-users-admin at lists.digium.com] On Behalf Of 
> Steven Critchfield
> Sent: Tuesday, July 20, 2004 7:00 AM
> To: asterisk-users at lists.digium.com
> Subject: Re: [Asterisk-Users] Echo on a PRI
> 
> On Mon, 2004-07-19 at 19:12, David Goldfein wrote:
> > Hi,
> > I recently set up the following in a production system (2.8 
> GHZ Xeon, 1 Gig
> > Memory, Dell 2650).
> > 
> > Telco - PRI - Asterisk - T1 - PBX
> > 
> > I am getting an occasional noticeable echo on some of the 
> phone lines
> > (random inbound and outbound).  Everyone I ask keeps 
> telling me that I can't
> > be having echo since I am on a PRI, which is a digital 
> circuit.  Ok, so I
> > can't be having echo, but I am!  Does anyone have any ideas 
> of what might be
> > causing the echo in this situation?  
> 
> Your PRI and the T1 itself cannot introduce echo on their 
> own. What you
> may see though is that you are introducing a delay as you traverse the
> asterisk link. Asterisk will buffer 8 bits per channel from the PRI
> before it send it down the T1 line to the PBX. This is a new 
> delay that
> is now added on to the latency your PBX introduces. 
> 
> A guess is that you also get the 2 machines fighting against 
> each other
> on the echo. I doubt you can turn off echo cancel in the PBX so you
> should try turning it off in asterisk. It should help reduce some
> latency in asterisk and let the PBX handle the rest of the echo cancel
> on it's own.
> -- 
> Steven Critchfield <critch at basesys.com>
> 
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