[Asterisk-Users] Echo

[Mark Spencer]

> i4l uses the modem.conf file, not the zapata.conf file.
> and no, it does not echo cancelation, i'm waiting for Mark
> to seperate it out from the zap driver, like he did for the
> dsp functions.

Unfortunately, echo cancellation is not as easy to pull out as the dsp
routines.  The problem is that in order to use an echo canceller like
"mec" and "sec" varieties, you must have very good correlation between
signal transmitted and signal received.  In other words, you need to know
that "this byte/short in this receive buffer was the one that we received
exactly when the physical device was transmitting that byte/short in that
transmit buffer".  That's why echo cancellation is done in-kernel, and in
zaptel, because we have that very correlation.

Mark