[Asterisk-Users] Weird Echo Problem

[Martin Roy]

Well I have 3 Digium TDM04B (4 port FXO) installed in my server. I use 
10 channels out of 12. There's 5 PCI slots on my motherboard, currently 
they fill the first 3 PCI slots. I can try to move them arround leaving 
one free PCI slot between each of them. The motherboard I use is a Tyan 
S2875ANRF with dual opteron, 1GB of RAM, 2x 74GB WD Raptor SATA 10k rpm 
HD, GeForce 4 MX400 AGP graphic card. I have Fedora Core 3 AMD 64bits 
installed on it. The motherboard is installed in an Antec 3U Rackmount case.

I have a Clipcomm device with 4 FXS ports so it's not part of the server 
and since I have currently only one user using a wireless analog  phone 
I don't know if I do have echo problem on this phone but I have 30 Cisco 
7960 phones working with SIP and my main concern is to have the echo fix 
on the Cisco phones.

I have a lot of stuff in my Rackmount cabinet could it create 
interference that create the echo? It's a real mess in there for now I 
have to clean it up but I can't put the entire network down during the 
week so I'll have to do it in the weekend... Otherwise I'll have a lot 
of people complaining hehe.

Thanks

Martin



Brian M. Arlinghaus wrote:

>> Ok I know I'm not the only one having echo problem with asterisk but 
>> the weird thing is that when I receive a call from a PSTN line on my 
>> TDM04B card I don't have any echo problem at the beginning of the 
>> call then after a few minutes I start having echo on my side only
>
>
>> (the person calling from a regular phone doesn't have any echo),
>
>
> I think that's the way it usually works... (i.e., only you hear the 
> echo).
>
>
>> then it stops and comes back all the way until the call is finished. 
>> It does the same thing on outgoing calls from my Cisco 7960 phone to 
>> the PSTN line.
>
>
> The echo happens when you make a call from IP to a 2-wire PSTN Phone.
>
>
>> I have no problem when it's an internal call from one 7960 to another 
>> one.
>
>
> And you shouldn't.
>
>
>> I tried a lot of different config in zapata.conf and the one that 
>> seems to work the best for now is this one :
>>
>> context=incoming
>> signalling=fxs_ks
>> echotraining=800
>> echocancel=yes
>> echocancelwhenbridged=yes
>> rxgain=0
>> txgain=0
>> immediate=no
>> busydetect=no
>> callprogress-no
>> musiconhold=default
>> usecallerid=yes
>> callerid=asreceived
>> group=1
>> channel => 1-8
>>
>> Any suggestion why it starts doing echo after 5 minutes or so?
>
>
> Martin,
>
> I had a similar problem, but the echo would just come and go.  What 
> are you using for your FXO ports?  Do you have the echo cancel turned 
> on when you create those channels?  I'm assuming you do since your FXS 
> ports start at one, and unless you specifically turned it off for your 
> FXO ports, the echo cancel setting (and all other settings) will carry 
> over from the previous channel settings.
>
> I have a T100P/PRI for my PSTN connection, and I changed the T100P 
> card to another pci slot on the same motherboard.  After that, the 
> echo problem disappeared.  I just used echocancel=yes and 
> echotraining=yes.  The default for echocancel is 128.  You can change 
> that number too.
>
> I never thought moving the cards around on the motherboard would 
> matter, but after reading a few other posts and seeing that this fixed 
> some other problems for people, I thought I would try it for my echo 
> problem.  In fact, my echo problem started after a support guy at 
> Digium had me move some cards around.  I erroneously attributed my new 
> echo to the latest version of Asterisk that he installed and not to 
> the moving of the pci cards.
>
> I have also heard that changing motherboards will change things too.  
> But that might introduce different issues....
>
> Regards,
> Brian