[Freeswitch-users] Linksys PAP2-T and echo

[Boris Kovalenko]

Hello!

     I found the root of echo problem - it is DECT. Echo present only 
when we are talking via DECT phones. Yes, I know DECT means additional 
coding + delay. So... it is possible to eleminate echo for DECT phones too?
> Hi Boris, what kind of analogue handsets do you have attached to the
> PAP2-T's? I have found with other ATA's (mostly Grandstreams) that it is
> the impedance settings for the handset that contributes the most to
> echo. Different handsets can be seup for different countries and
> sometimes you have to adjust the ATA to match.
>
>
> Regards
> Brian
>
>
>
> On 01/11/2011 02:39, Boris Kovalenko wrote:
>> Hello!
>>
>>        Steve, my configuration is:
>>
>> PAP2-T (A) ---- FreeSwitch --- PAP-2T (B)
>> I tried Freeswitch in all modes: default, proxy_media, bypass_media. The
>> echo is always present. User A hears its own echo, and user B hear its own.
>>
>>> Hi,
>>>
>>> The echo canceller in the SPA3102 is a disaster, but the ones in the
>>> PAP2T and SPA2102 shouldn't give you problems. If you use the default
>>> gains you shouldn't really notice echo. If you set some wild gains you
>>> might bee poor results. Are you sure the echo originates from the PAP2T,
>>> and not some other part of the signal chain?
>>>
>>> Steve
>>>
>>>
>>> On 11/01/2011 12:42 AM, Boris Kovalenko wrote:
>>>> Hello!
>>>>
>>>> Steve, Darcy, I've played ... no success :( Setting FXS to -15 do echo
>>>> acceptable but I still can hear it. So there is no way to eleminate echo
>>>> with Linksys devices? Only to buy more professional devices like Addpac?
>>>>> on your pap2t web interface, go to voice, advanced, select the line, the
>>>>> settings below will allow you to play with echo cancellation.  However, you
>>>>> also need to go the the regional tab in voice and play with the fxs input
>>>>> and output gains, the voice gain on the pap2t or any linksys gateway, will
>>>>> impact the echo on the line.  This is most likely where your problem is.
>>>>> You might not be able to cure the echo on every call, but you should be able
>>>>> to make it acceptable.
>>>>>
>>>>> Darcy
>>>>>
>>>>>
>>>>> Audio Configuration
>>>>> Preferred Codec:        Second Preferred Codec:
>>>>> Third Preferred Codec:        Use Pref Codec Only:
>>>>> Silence Supp Enable:        Silence Threshold:
>>>>> G729a Enable:        Echo Canc Enable:
>>>>> G723 Enable:        Echo Canc Adapt Enable:
>>>>> G726-16 Enable:        Echo Supp Enable:
>>>>> G726-24 Enable:        FAX CED Detect Enable:
>>>>> G726-32 Enable:        FAX CNG Detect Enable:
>>>>> G726-40 Enable:        FAX Passthru Codec:
>>>>> DTMF Process INFO:        FAX Codec Symmetric:
>>>>> DTMF Process AVT:        FAX Passthru Method:
>>>>> DTMF Tx Method:        DTMF Tx Mode:
>>>>> DTMF Tx Strict Hold Off Time:        FAX Process NSE:
>>>>> Hook Flash Tx Method:        FAX Disable ECAN:
>>>>> Release Unused Codec:        FAX Enable T38:
>>>>> FAX T38 Redundancy:        FAX Tone Detect Mode:
>>>>>
>>>>> -----Original Message-----
>>>>> From: Steve Underwood
>>>>> Sent: Monday, October 31, 2011 11:11 AM
>>>>> To: FreeSWITCH Users Help
>>>>> Subject: Re: [Freeswitch-users] Linksys PAP2-T and echo
>>>>>
>>>>> On 10/31/2011 10:58 PM, Boris Kovalenko wrote:
>>>>>> Hello!
>>>>>>
>>>>>>
>>>>>>            I'm wondering if it is possible to solve echo with Linksys PAP2-T
>>>>>> devices. Does anybody here uses it? I read many articles and still can't
>>>>>> understand how to eleminate echo :( I read
>>>>>> http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation and found
>>>>>> that Asterisk has its own EC. Does Freeswitch has it too? I found this
>>>>>> article http://docs.freeswitch.org/echo_can_page.html but can't
>>>>>> understand - has Freeswitch EC or not? If yes - how to turn it on and off?
>>>>> Neither Asterisk or Freeswitch will echo cancel your PAP2T. Echo
>>>>> cancellation over IP is very problematic, and hardly ever attempted. The
>>>>> PAP2T should be echo cancelling for itself, and they usually do a fairly
>>>>> good job of this. I don't think it is configurable. Its always on.
>>>>>
>>>>> Steve
>
>
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-- 
Regards,
Boris