[Asterisk-Users] How to ensure that software echo cancellation ison?

[Rich Adamson]

> 
> Problem solved.
> 
> this zapata.conf works (i.e echo is gone, echo cancellation is detected 
> on "zap show channel"):
> context=from-pstn
> switchtype = national
> signalling = pri_cpe
> echocancel=yes
> echotraining=500
> echocancelwhenbridged=yes
> faxdetect=incoming
> group = 0
> channel => 1-8
> 
> this zapata.conf has echo cancellation not work:
> context=from-pstn
> switchtype = national
> signalling = pri_cpe
> group = 0
> channel => 1-8
> echocancel=yes
> echotraining=500
> echocancelwhenbridged=yes
> 
> And if I add "faxdetect=incoming" as the last line in that one, asterisk 
> doesn't even start.  I get the "Ouch" message and asterisk crashes.
> 
> Lesson learned: the order in which lines appear in zapata.conf does matter.
> Questions to be asked:  is that expected behavior? is it documented 
> somewhere?

Yes. For the most part, the "order" of the statements does not make
any difference. However, what you've learned from above is not the
order at all; its that your echo statements were not stated before
the channel => 1-8 statement.

In other words, had those echo statements been included prior to the
channel statement (as in your working cofig), the order within the 
channel definition "section" is irrelavent.