[Asterisk-Users] Asterisk and echo

[Aldo Bergamini]

Since a couple of days I using an Asterisk server. I noticed something
obvious to anybody dealing with telephony since any longer time than
myself; echo is nasty...

Is it correct to say that the difference between a conversation between
SIP phone, Asterisk, an ISDN BRI line and a GSM phone is entirely
digital, whereas I do have a remote analog portion of the sound link only
if I dial an analog landline subscriber?

At times I do hear a bad echo of my own voice when calling old POTS users
(while they do not report any echo), while so far I did not have any echo
with cellphones.

Can I do anything with echo suppression on my side? Is it beyond the
features of my cheap (convenient..) Fritz PCI card?

Thanks,
Aldo