Echo problem

hi to all!

i’ve put up my first asterisk server. i’ve used the x-lite soft phone and dlink dvg-2001s ata adapter but i got the same problem

i’ve created local 101,and local 102 locally (the same site) using x-lite and dvg-2001s respectively and local 701 using x-lite on my remote site. when i try to call local 101 to local 102 and vice versa there is no echo present, the problem is that for instance when i try to call local 701 from local 101 or 102 and vice versa i always here an echo on local 101 or local 102 but no echo on local 701.

here is my sip.conf

[loc101]
type=friend
secret=xlite1
qualify=yes
nat=no
host=dynamic
canreinvite=no
context=internal

same configuration on local 102 and 701. i try also to add echocancel=yes, echocancelwhenbridged=yes but still give me the same effect.

when i try to look at the log messages it gives me this message “NOTICE[25027]rtp.c:Comport noise support incomplete in Asterisk (RFC 3389). Please turn off on client if possible” when i initiate a call. i don’t know if it has to with my echo problem

can you help with my problem? i will appreciate it very much