[asterisk-users] echo over digital line

[Vieri]

Hi,

I'm using a 4-port BRI card (b410p) to make and receive calls (via chan_misdn):
http://www.digium.com/en/products/digital/b410p.php

This card supposedly has hardware echo cancellation.

How can I check that echo cancellation is actually ON (taps, etc) on a given misdn channel (like with the "zap show channel X" command). "misdn show channel X" doesn't seem to show more info than "misdn show channels" and in any case there's no info on echo cancellation. I also issued an "misdn toggle echocancel mISDN/1-u2528" (on a live call) and flipped several times between echo ON/OFF without subjectively noticing any difference (it's odd because I was calling from a SIP softphone to a remote POTS analog phone and the latter usually experiences echo issues). I couldn't reproduce the echo problem today but in some occasions the remote POTS called party complains they hear echo of their own voice (the "called" user has a standard analog phone, no headsets, etc., and usually never has echo problems).

According to this article:
http://www.audiodesignline.com/howto/206800151;jsessionid=UJRLVDJCJT2QMQSNDLPSKHSCJUNN2JVN?pgno=1
I (on the Asterisk system) should take care of the remote user's echo issue, ie. either my BRI card or my Asterisk add-on software should correctly echo cancel.

How can one disable hardware echo cancellation altogether on the b410p?

Which software echo cancellation can I try on misdn channels (apart from the experimental oslec on misdn)?

Is there a way to see the "echo cancellation details" of a live call?

Thanks,

Vieri