[Asterisk-Users] sip call echo cancellation

[Matt Hess]

I have echo cancellation on in the mp-108 as well as silence 
suppression.. tinkering with these two settings has not yet yielded any 
happy results.. which is why I'm asking if the asterisk system has any 
possible echo cancellation that may help alleviate this issue as it's 
not only seen on the mp-108 but a few sip phones as well such as a 
budgetone 2 and an ipdialog.. I have a feeling this has to do with voice 
output levels.. but it's just a hunch that adding a bit of a reduction 
to the output audio on the pri trunks will help..

as I remember it.. if point A calls point B and point A hears echo and 
point B does not then it's something like an impedance problem on the 
far end.. or wire center (CO) at that point.. but an impedance mismatch 
can occur also at a pstn ingress point such as the ILEC side of the pri 
lines.. or maybe I'm wrong..




Steve Clark wrote:

> Matt Hess wrote:
>
>> I haven't found much info that stands out to me in regards to echo 
>> cancellation in sip to sip calls..
>>
>> My setup is this..
>> I have a key system connection to an audiocodes mp-108 which connects 
>> to asterisk via sip and asterisk passes the call over to a ser proxy 
>> and ser passes the call to either an internet voice terminator for 
>> long distance or a local pstn gateway.. the local gateway is a lucent 
>> max tnt with 10.1.1 software load.. it dumps the sip calls onto pri 
>> trunks..
>>
>> I'm still getting feedback from the office as to whether or not echo 
>> is heard on local or long distance.. incoming outgoing etc.. so I 
>> know which part to troubleshoot.. if the echo is on egress or 
>> ingress.. I know it isn't the local key system with echo as it's 
>> almost all digital apart from the analog connection from key system 
>> to audiocodes sip gateway as I also have a few ip phones which 
>> connect to asterisk that experience similar echo issues.. remote 
>> callers don't seem to hear any echo so it would appear to be an 
>> impedance issue somewhere remotely on the pstn..
>>
>> My thinking is that the mismatch may be on the local tnt gateway but 
>> I'm not 100% positive of that.. I know ingress calls to the sip 
>> network have echo and those flow through the pri lines to the tnt so 
>> I'm starting there with that gateway but I'm looking for something 
>> possibly on asterisk that can help with pure sip call echo 
>> cancellation.. does anyone have any ideas as to what may help?
>>
>>
>>
>>
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>
>
> In the MP-108 try turning on Silence Suppression and Echo Cancellation.
>
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