[asterisk-users] [1.6.2.9] Echo even when using headset?

[Gilles]

Hello

	I just set up Asterisk 1.6.2.9 through packages on  a test host
running Ubuntu 11.04, configured sip.conf/extensions.conf, and
launched EyeBeam 1.5.20 to run the echo test.

For some reason, even through I'm using a headset, there's a lot of
echo and after a few seconds, it sounds like it enters a very fast
loop before the echo stops somewhat. IOW, unusable sound.

Here's a recording:
www.megaupload.com/?d=146L0HL6

FWIW, EyeBeam has both "Use acoustic echo cancellation (AEC)" and "Use
gain control (AGC)" checked.

Here are the two files:
;=========== sip.conf
[general]
context=dummy
port = 5060
bindaddr = 0.0.0.0

disallow=all
allow=ulaw
allow=alaw
allow=gsm

nat=no
qualify=yes
host=dynamic

[fred]
type=friend
context=internal
secret=1234
qualify=yes
host=dynamic

;=========== extensions.conf
[dummy]

[internal]
exten => 600,1,Playback(demo-echotest)
exten => 600,n,Echo
exten => 600,n,Playback(demo-echodone)
exten => 600,n,Hangup()
;=========== 

Are there settings I should(n') use in either Asterisk or EyeBeam to
explain/solve this issue?

Thank you.