[asterisk-users] tuning software echo cancellation

[Jeff LaCoursiere]

We have been distributing asterisk servers for several years now, and early on 
decided that hardware echo can was the way to go.  Our first few boxes without 
it had horrid echo problems, and attempts at tuning in 2006 didn't make any 
difference.

We installed a new server yesterday at a client's location with a Rhino 4 port 
FXO card (HW EC included), and when an inbound call was answered the oddest 
shrieking sound was heard by the caller, and the internal SIP phone heard 
nothing at all.  On a call with Rhino support they disabled the echo 
cancellation module and all was well, though of course we have a horrible echo 
problem now.

We are going through an RMA process with Rhino, which is fine (kudos for them 
to cross ship - really good support team there).  But the client is of course 
chomping at the bit to get the system live.

We are totally out of touch on the subject of software echo cancellation in 
asterisk.  The system is running 1.4.28 and Dahdi 2.2.1-RC2.  I understand that 
when Dahdi detects no HWEC, it enables SWEC by default. Is there anything I can 
do to tweak the settings to try and make this liveable for the client until we 
get the card?  The server is in the Caribbean, so it may actually be a bit 
before the card arrives.  We would love to get them running before then, but it 
is so bad right now that we cannot.

Thanks for any links to info...

Cheers,

j