[asterisk-users] TDM400 native bridge echo

[Shaun Kruger]

I have a TDM400 with an FXS and FXO interface.  I have adjusted the TX
and RX gain for both the FXS and FXO channels so that everything is
balanced.

I hear myself very loudly with no lag.  I also get alot of background
noise when the bridge is formed between the FXS and FXO channels.  I
have read the following articles:
http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation
http://www.voip-info.org/wiki/view/Causes+of+Echo

I have read these multiple times.  My system is now useable, but it's
definitely worse than when I plug the phone directly into the wall.

My loadzone is 'us'.
I have the following in my zapata.conf
usecallerid=yes
transfer=yes

channel => 1
context=outbound
mailbox=00
channel => 2

echocancel=yes
echocancelwhenbridged=yes
context=inbound
signalling=fxs_ks
faxdetect=incoming
busydetect=yes
busycount=5
rxgain=5.2
txgain=-0.5
channel => 3

Is there anything I'm missing?  I assume there is because it's not
working as well as I had hoped.  Any suggestions of what to try next,
what to look for, or what additional documentation I should be reading
would be much appreciated.

Shaun

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