[Asterisk-biz] PRI and echo cancelation ...

[Rob Lith]

On 8/17/05, Michael Blood <Michael at matraex.com> wrote:

> Agreed,  this should be on the Users List.
> My experience has been that PRIs have much less trouble.
> The echo typcially comes from the analog to digital conversion.

No, it happens because of the impedence difference between 2 and 4
wire analogue lines which causes a reflection point - this is not
possible on Digital lines.

The only instance you'll get classis 'echo' is when calling from you
ISDN to an analogue line on the far end.

> I personally believe the reason for this is that the Analog to Digital
> conversion that happens at the telco is done with much higher quality
> equipment with much higher quality echo cancellation than if it is done on
> your asterisk box.
> 
> Here is an interesting read
> http://www.voip-info.org/wiki-Asterisk+echo+cancellation
> 
> Google Search:
> site:voip-info.com echo cancellation
> 
> Michael

Regards
Rob