[Asterisk-Users] Echo and crackle

[Steve Jones]

I went through the same thing on my home system a couple months ago, and
asked similar questions..  The "conventional wisdom" is that "it
depends"...  It depends on your local loop length, quality, taps on the
line, etc..  

It seems that most people who have the sangoma cards with hardware echo
cancellation are happy, but I didn't have that kind of money to spend on
my home system, so I bought the TDM400 card.  In my case, I bought two
FXO and one FXS....  Also just "in my case", the difference was huge -
All of a sudden my echo problems were gone.  So, although I probably
would have been better off with the hardware echo, in my particular
case, the Digium works great, and did make a huge difference over the
voice modem I had been using.

Just for comparisons sake, my two FXOs are connected to:  1 Vonage ATA
(Motorola), and one Verizon pots line.  I am about 2.5 miles from the
CO, but I don't know the path that the cable takes, or if there's a SLC
somewhere, so I don't know how long the loop is.  The line is DSL
qualified, so I don't think there's a SLC, but I'm not positive..

Since you've already got the card, you'd probably be able to get the FXO
for around $65, right?  I'd say that is your best bet, with very little
money risked..

Good luck!!

-Steve

-----Original Message-----
From: M.Hockings [mailto:veeshooter at hockings.net] 
Sent: Saturday, June 17, 2006 1:23 AM
To: asterisk-users at lists.digium.com
Subject: [Asterisk-Users] Echo and crackle

We are running asterisk with a single POTS line for local calls and a 
voip line for long distance.  Whenever we receive a call on the POTS 
line it is more than likely, but not always, going to have significant 
distracting echo.  In addition to that there is occasional heavy crackle

or static.  I have tried to follow the guidelines at :
http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation
but it does not seem to have made much difference.

Currently we are using a X101P for the POTS line and a TDM401B (TDM400P 
with one FXS port) for the conventional telephones.  From what I have 
read, it may help to use an FXO port on the TDM400P rather than the 
X101P for the POTS line.

What is the "conventional wisdom" about the echo in this configuration 
and what causes the crackle and how should I tackle that?  I have tried 
rebooting/power-cycling the machine to reset the hardware but it really 
hasn't noticeably helped.

Is there anything else that I can try?

Thanks,  Mike