[asterisk-users] Cianet channel bank with noise and echo

[Steve Howes]

On 24 Nov 2009, at 13:48, jefferson alexandre wrote:
> Steve, the hardware don't have echo cancellation.

Thats probably it.... You're relying on Asterisks software echo  
canceling.... I have seen mixed results. Have you tried adjusting  
gains? I'd do the following

1. Turn off echo canceler (makes it more obvious whilst you're trying  
to remove it)
2. Turn down both gains
3. listening' inside your network (i.e. listening to audio coming to  
your network from the PSTN), adjust the gain upwards until it sounds  
suitable
4. 'listening' outside of your network (i.e. listening to audio coming  
from your network to PSTN) do the same.
5. Test for echo. Adjust the gains down for the sound you hear back  
(i.e. if you hear person inside your network echoing, adjust the gain  
in '4').
6. Try and get it as close to echo free as you can using this method
7. Enable any echo canceling you can find to 'tidy up' the leftover  
echo, try various ones if you need to. voip-info.org/wiki may help
8. Buy hardware echo cancelers next time ;)

S