Echocancel=yes or no when has hardware EC?

hi all,
How to set echocancel in chan_dahdi.conf when there is hardware echo cancellation module?
If it should be set yes or no?
Any answer will be appreciated.


If you set no, then no echo canceler, either hardware or software,will be used.

If you set yes, the a hardware echo canceler will be used, if available; and if not, then software will be used.