[asterisk-dev] Zaptel Echo Cancellation

[Florian Overkamp]

Hi,

Eric "ManxPower" Wieling wrote:
>> Would you mind expanding on that? 16ms seems like the bare minimum?
>>
>> Is there not an inherient delay of several ms due to CPU and encoding
>> overhead etc or is this not a factor in the calculations? I'm just
>> wondering what kinds of delays play into this or is the only thing that
>> matters the delay on the PSTN before the signal hits the card?
> 
> The PSTN delay is what matters.  Echo must be removed at the PSTN 
> interface.

Using spike-tests we've established that for the Netherlands 16ms will 
not be enough to cover PSTN delay with calls from the smaller areacodes, 
in particular if you use any non-incumbent operator. We've beefed up our 
systems to cope.

Florian