[Asterisk-Users] TE405P and echo

[McQuiggan, Mark xt46480]

>Peter Svensson wrote:
>
>>On Tue, 22 Mar 2005, McQuiggan, Mark  xt46480 wrote:
>>
>>  
>>
>>>I am using a SIP softphone (X-lite, SIPPS or Firefly) connected to an
>>>Asterisk v 1.0.3 PBX.  The PBX is also connected via a ISDN-PRI crossover
>>>cable to a Avaya Definity Generic 3 PBX via a TE405P card. All outside of
>>>the office calls go through the Definity.  Here's the issue:
>>> 
>>>Calls to internal SIP extensions, Definity extensions, other offices
within
>>>our private network (through the Definity), and cell phones are great.
When
>>>I call outside of the office to POTS lines (like my home), there is a
most
>>>noticeable echo of my voice.  The party on the line hears no echo.  Any
>>>efforts on the configuring the SIP softphones, and within zapata.conf,
have
>>>been for naught.
>>> 
>>>Is this problem common for ISDN-PRI connections?
>>>    
>>>
>>
>>It is a problem you will see when calling an analogue subscriber over a 
>>link with a long latency (such as VoIP). The echo will most probably be 
>>generated by a 2- to 4-wire hybrid at the far end. In a pure amalogue/tdm 
>>path you would perceive the reflected energy as a plesent sidetone. As 
>>soon as the latency increases to 50-100ms the refelcted energy will be 
>>perceived as an echo instead.
>>
>>The options available to you are to live with the echo of your own voice 
>>or to insert an echo canceller at the pstn interface. Asterisk includes an

>>echo canceller that may or may not be good enough. It seems to like some 
>>pstn interfaces and not others. If the Asterisk echo canceller is not 
>>enough you may consider an expensive inline echo canceller. 
>>  
>>
>
>The definity has echo cancellation. Try turning that on.
>
>-SteveK
 
Thanks for both of your replies.  
 
My Definity connection is on a TN464C (the TN464G has echo cancellation) and
I was hoping to try a software solution first before investing in the
hardware (we would also have to upgrade our Definity software, so the total
cost is quite high).
 
I have noticed that any of the zapata.conf echo cancel parameters seem to
have no effect on an ISDN-PRI line, using pri_net signalling (I used the
voip-info.org wiki for the configuration).  If this is true, and I am not
making some dumb mistake, is there another signalling mode that I can use on
a Definity that will take advantage of echo-cancel?
 
Barring that, I am using a Plantronics DSP-100 headset with X-lite under
Windows.  Can I set up echo-cancelling there?
 
Thanks,
 
Mark.
 
P.S.  Is there a website where I can post replies to this mailing list?
Cutting and pasting into Outlook is just darn goofy.  M.

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