[Asterisk-Users] Tiny Echo on PSTN via Zaptel

Tony Nichols tony.nichols at gmail.com
Thu Sep 29 05:33:03 MST 2005


I have had problems between the sip/FXO lies and was able to "kill" the echo
by trying different combinations of the echocancel line to 64 (I think it
has settings in 32 bit increments)
Just kept trying different ones till it went away. Here is my config:

group=1
context=line1
signalling=fxs_ks
usecallerid=yes
callerid=asreceived
echocancel=64
echocancelwhenbridged=yes
callgroup=1
rxgain=1.2
channel => 1

context=line2
signalling=fxs_ks
usecallerid=yes
callerid=asreceived
echocancel=64
echocancelwhenbridged=yes
callgroup=1
rxgain=1.2
channel => 2
musiconhold=default
context=line3
signalling=fxs_ks
usecallerid=yes
callerid=asreceived
echocancel=64
echocancelwhenbridged=yes
callgroup=1
rxgain=1.2
channel => 3

group=2
context=line4
signalling=fxs_ks
usecallerid=yes
callerid=asreceived
echocancel=96
echocancelwhenbridged=yes
callgroup=2
channel => 4

Hope this helps!

t o n y

On 9/28/05, Shaw Terwilliger <sterwill at sourcegear.com> wrote:
>
> I'm using Asterisk 1.0.9, a Digium TE210P dual T1 card, and two Rhino
> channel banks (one 12FXO/12FXS, the other 24 FXS). So it's an analog
> phone on the inside connected to one of the FXS ports, and PSTN line
> connected to one of the FXO ports.
>
> My problem is that as soon as I hear the _first_ ring when I dial out
> through the PSTN line, I hear a tiny echo on the phone (I estimate
> between 20ms and 40ms), which never goes away for this call. It's just
> loud enough to bug the heck out of me when I'm talking (I could estimate
> the gain relationship with ztmonitor if it would help). The sound
> on the recipient end of the connection is perfect.
>
> If I make a call from the phone to the another internal extension (another
> phone on an FXS port), there is no echo. If I call into Comedian mail,
> there is no echo.
>
> I've checked all my gains. The "internal" gains were a bit loud to start
> with because of the powered phones, but now they all fall comfortably
> within
> ztmonitor's dynamic range display. The PSTN line is pretty good at tx 0
> and
> rx 0, so I left it. I've tried turning them down, but that didn't kill
> the echo.
>
> My zapata.conf includes these lines at the bottom:
>
> echocancel=yes
> echocancelwhenbridged=no
> echotraining=yes
>
> context=companyA-pstn
> txgain=0.0
> rxgain=0.0
> signalling=fxs_ks
> group=1
> channel=1-7
>
> context=companyB-pstn
> txgain=0.0
> rxgain=0.0
> signalling=fxs_ks
> group=2
> channel=11-12
>
> context=internal
> txgain=-12.0
> rxgain=-8.0
> signalling=fxo_ls
> callerid=asreceived
> group=3
> channel=13-48
>
> When the calls are connected, I can use "zap show channel 11" and verify
> that the echo cancellation is ON. But I can still hear one.
> I've also tried echocancelwhenbridged=yes, but it didn't make any
> difference.
>
> --
> Shaw Terwilliger <sterwill at sourcegear.com>
> SourceGear LLC
>
>
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--
A.G. (Tony) Nichols
I.S. Manager
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