[Asterisk-Users] Channel Bank Echo

[Andrew Kohlsmith]

On January 29, 2005 12:31 pm, Matt Schulte wrote:
> We are a voip terminating company, we're using Channelbank with FXS
> modules, Rhino, CAC, etc.. What we're wondering is, is how to would you
> echo cancel a channelbank. Of course we're realizing that cancel'ing on
> the T1 (on Ast) does no good (we think?) because the analog conversion
> is at the channelbank. Suggestions? Lowering the gain helps but we're
> looking for a real solution to this. Thanks.
>
> <PSTN?> -- <VOIP Network> -- <Asterisk> -(T1)- <channel bank> --
> <analog>
>   ^echo heard

If the echo is being heard on the far side then you are generating it at your 
hybrid.  Your diagram is not clear since it was wrapped.

I have used the Adit600 and Access Bank 1s with great success -- they do not 
generate echo (i.e. nobody we've called has heard echo) -- we do, however, 
hear echo from time to time, even on our PRI.  Asterisk's echo cancellation 
is either getting disabled accidentally or it is not working worth a 
damn.  :-(

You can use Tellabs echo cancellation units on T1 and PRI -- these are 
carrier-grade hardware echo cancellers.  I haven't any experience with them 
yet (waiting for mine to arrive).

-A.