[Asterisk-Users] Are my expectations too high?

[Andrew D Kirch]

Derek Lee-Wo wrote:
>> Get an FXO card with hardware echo cancellation. I use the Sangoma
>> A20002D (four FXO ports with echo cancellation). It definitely costs
>> more, but the hardware echo cancellation makes a huge difference in call
>> quality! Software echo cancellation doesn't really work...
>
> With this card, would you say your audio quality is identical to that
> of an analog phone connected directly to the PSTN?  I'm trying to
> understand if I should expect "some" audio degradation when going
> through Asterisk. 
Everything causes degredation.  Yes the card is a codec so it will not 
be "perfect". 
Many modern telephones are also codecs.  The question you're trying to 
ask is is this
degradation noticeable?  The answer to that is obviously no.  There is 
an application out
there that might benefit you in a situation like this.  Go look through 
your zaptel source
tree for "fxotune" and see if it cant possibly correct some of the 
problem you're having. 
After you've tried that I'd suggest posting a .wav file of exactly what 
you're hearing (there are
recording functions in asterisk) and maybe someone that's heard the 
degredation you're hearing
before will reply.


Andrew