With following config, I can make cheap long distance voip call to China
sip.conf
[voipstunt]
type=friend ; (or "peer" if we don't need incoming call)s
host=sip.voipstunt.com
disallow=all
allow=ulaw
allow=alaw
allow=gsm
allow=g726
username=myusername
fromuser=myusername
secret=secret
qualify=1000 ; optional
canreinvite=no ; new SIP servers don't like reINVITEs
dtmfmode=inband ; only inband currently works, and not that well
extensions.conf
[out-voipstunt]
; outgoing voipstunt
exten => _0086.,1,Dial(SIP/${EXTEN}@voipstunt)
[default]
; include outgoing voipstunt
include => out-voipstunt
sip.conf
[voipstunt]
type=friend ; (or "peer" if we don't need incoming call)s
host=sip.voipstunt.com
disallow=all
allow=ulaw
allow=alaw
allow=gsm
allow=g726
username=myusername
fromuser=myusername
secret=secret
qualify=1000 ; optional
canreinvite=no ; new SIP servers don't like reINVITEs
dtmfmode=inband ; only inband currently works, and not that well
extensions.conf
[out-voipstunt]
; outgoing voipstunt
exten => _0086.,1,Dial(SIP/${EXTEN}@voipstunt)
[default]
; include outgoing voipstunt
include => out-voipstunt