[Asterisk-Users] EC needed in all-digital situation?

[Andrew Kohlsmith]

On Thursday 15 June 2006 10:22, Warren wrote:
> I was just told that for my forthcoming system I will be getting a data
> T-1 instead of a voice T-1.  Given that all of the handsets will be voip
> phones, no analog at all, do I need echo cancellation?  I looked at the
> voip-info wiki and it seems to me that the answer should be "no" but I
> would like to confirm that.

All-digital setups do not *generate* echo since there is no hybrid circuit to 
reflect energy.  However all-digital systems can still have echo if the 
far-side is a 2-wire system and the latency is sufficiently high.  (Anything 
with a PCI bus can bring this latency up easily.)

Also, if you have an ueber-cheap phone which acoustically couples the speaker 
in the handset with the mic you can introduce echo on your all-digital system 
that way.  The same goes for cheap speakerphones and/or acoustically "hard" 
rooms.

-A.