[Asterisk-Users] Question on echo's for Canadian Asterisk users ...

[paul at freestylenetworks.com]

Thanks for the tips ...

Like you said, dealing with carrier is not going to get me anywhere.
The only thing GT recommended was grounding the server chasis :P


I turned the echo cancellation with the same parameters you used and 
It doesn’t even make a difference. I dug further into the 
zaptel/Makefile
To find the the echo cancellation algoriths:

#KFLAGS+=-DECHO_CAN_STEVE
KFLAGS+=-DECHO_CAN_STEVE2
#KFLAGS+=-DECHO_CAN_MARK


None of these were listed at all in the Makefile, so I added them
And tried a recompile. Still a bad echo. It is like the echo 
cancellation
Is not even working. Is there a way to verify its active or not?

Cheers,

Paul Seniuk 




-----Original Message-----
From: akohlsmith-asterisk [mailto:akohlsmith-asterisk at benshaw.com] 
Sent: September 4, 2004 3:51 PM
To: asterisk-users
Subject: Re: [Asterisk-Users] Question on echo's for Canadian Asterisk 
users ...


On Saturday 04 September 2004 16:57, paul at freestylenetworks.com wrote:
> Has anyone has issues with echo using a Wildcard with a PRI from a 
> major Canadian Telco? (Bell, Telus, AllStream, Sprint, Group 
Telecom).

I have a PRI with Bell Canada in Listowel, ON  (519-291-XXXX).

I have echo on some calls but not all -- it doesn't seem to have 
anything to 
do with what switch it's terminating on.  Calling anywhere in Fordwich 
echos 
rather badly as do some Toronto numbers.  The echo occurs on incoming 
and 
outgoing calls.  (we only call out on the PRI for local, 800 and fax 
numbers).

> We are using a T1 from GT that is giving use annoying echos whenever 
a 
> SIP/IAX2 client calls a local analog line. Calling cells phones is 
no 
> issue since its digital. Regardless, there should
> be no issue with echo on a PRI at all.

All that PRI gives you is one less hybrid in the circuit.  That's it.

> NOC at GT is telling us that there is no echo cancellation enabled 
on 
> this PRI. 'Talk to your rep' was the response I got .... To me 
that’s 
> crap, because they shouldn’t be selling PRI's without this essential 

> feature.

Depending on who you talk to you will hear responses like
1. "I have no idea what you're talking about."
2. "We don't have echo cancellation hardware available on any PRI." 3. 
"You must specifically provision the PRI with echo cancellation."

I've found acceptable echo cancellation on the PRI with Asterisk's 
echo 
cancellation software on the TE405P with the following:

- agressive cancellation
echocancel=yes
echocancelwhenbridged=yes
echotraining=500

No need to worry about the echo canceller killing fax/data connections 
since 
just like the real echo cancellation hardware, asterisk will disable 
the echo 
cancel routines when it hears the correct disable tone on the line.  
You'll 
see something like "zaptel Disabled echo canceller because of tone 
(tx) on 
channel 13".

We were really having a lot of echo troubles but 20040831 CVS HEAD 
seems to 
have really helped, although it was certainly acceptable with 20040806 
CVS 
HEAD.

I haven't been able to locate a good hardware echo canceller on ebay 
yet (I 
keep missing the auctions).  :-)

-A.
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