[Asterisk-Users] Are my expectations too high?

[Matthew Crocker]

If you use g.711 you should expect the same quality because that is  
essentially the same codec the PSTN uses in T1s.
If you use g.729 you should expect some audio degradation as it is a  
lossy compression codec. You will lose quality but gain significant  
bandwidth reduction

Use a high quality phone (I use Cisco 7912s), use a high quality PSTN  
interface.  T1 is better but a good analog FXO card should be fine.

-Matt

On May 23, 2006, at 9:04 AM, 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.
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--
Matthew S. Crocker
Vice President
Crocker Communications, Inc.
Internet Division
PO BOX 710
Greenfield, MA 01302-0710
http://www.crocker.com