[Asterisk-Users] Some echo?

[jj]

yes it sounds very familier. I would suggest not tweaking settings  
for gain on a T1, it should work fine at 0db.

I got tired of chasing down these issues with our/other carriers  
because the software echo cancellor on the system is just not capable  
of performing this task. I suspect the new cards with the onboard DSP  
will be much improved. I broke down and bought dedicated gear to  
handle and it has been flawless - zero complaints since installed.  
But if you go this route get your checkbook out, they are not cheap  
unless you go the ebay route.

As a side note the echo gear has been keeping a running tab on the  
worst connections on each of the channels. per the asterisk docs  
"Accordingly the number of taps equate to a 2ms, 4ms, 8ms, 16ms or  
32ms tail length." or a maximum of 32ms cancelling. In a good world  
this would be sufficient. From my measured stats you can see where  
this is not even close to doing the job. This particular hardware  
performs upto 192ms with no problem.

Good Luck

CHANNEL           1         2         3         4         5         6
WORST DLY        --        --        --        --        --        --
TIME             --        --        --        --        --        --
DATE             --        --        --        --        --        --
CHANNEL           7         8         9        10        11        12
WORST DLY        --      9 ms     10 ms     10 ms     25 ms     21 ms
TIME             --  14:21:51  11:20:26  15:45:22  10:43:54  13:22:52
DATE             --  07/13/05  06/15/05  07/19/05  07/18/05  06/07/05
CHANNEL          13        14        15        16        17        18
WORST DLY     27 ms    108 ms     36 ms    159 ms     37 ms    150 ms
TIME       14:33:13  10:15:25  15:09:07  11:30:02  10:41:32  15:09:07
DATE       07/13/05  06/28/05  07/06/05  07/14/05  07/11/05  07/07/05
CHANNEL          19        20        21        22        23        24
WORST DLY    123 ms    168 ms    135 ms    144 ms    184 ms        --
TIME       13:30:32  13:22:28  08:05:15  12:02:27  07:47:07        --
DATE       05/27/05  06/23/05  06/02/05  06/24/05  05/31/05        --

On Aug 4, 2005, at 4:10 PM, Robbie Hughes wrote:

> I have a 12 channel PRI with SNOM 190's and asterisk CVS from January.
> Most calls are fine, all incoming calls are fine, but I am getting  
> echo on a significant number of outgoing calls.
> The person on the other side hears a perfect call, but the SIPphone  
> side gets to hear themselves.
>
> It happens 100% of the time to some numbers (outgoing only), and  
> only sporadically to others.
>
> Has anyone ever experienced this?
> the RTT to the phones from the server is less than 10ms and it is a  
> 100mbit network with no traffic and cisco switches.
>
> zapata.conf attached below:
> Note: The commented out gain of +2 on outgoing seems to make no  
> difference to the effect.
>
>
> Has anyone got any ideas?
>
> ;
> ; Zapata telephony interface
> ;
> ; Configuration file
>
> [trunkgroups]
> group => 1,16
> [channels]
> spanmap => 1,1,1
> language=en
> context=from-pstn
> rxwink=300              ; Atlas seems to use long (250ms) winks
>
> usecallerid=yes
> hidecallerid=no
> callwaiting=yes
> usecallingpres=yes
> callwaitingcallerid=yes
> threewaycalling=yes
> transfer=yes
> cancallforward=yes
> callreturn=yes
> echocancel=yes
> echocancelwhenbridged=yes
> echotraining=800
> ;txgain=2.0
> txgain=0.0
> rxgain=0.0
>
> group=1
> callgroup=1
> pickupgroup=1
> immediate=no
> pridialplan=unknown
> overlapdial=yes
> signalling=pri_cpe
> switchtype=euroisdn
> channel=> 1-12
> faxdetect=both
>
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