[Asterisk-Users] IAX problem; one end sounds like on fast forward

[Wojciech Tryc]

Hi,
I have some issues with communication between to * servers. They are
connected over DSL (3Mbps). One is behind NAT and the other on routable
network. Almost every time caller will hear the other end like fast forward
while the other end will have perfect quality. It doesn't matter if we use
SIP phones (Cisco and Grandstreams) or analog sets via Sipura-2K. If I call
the city through Mediatrix 1204 the quality is perfect. I am suspecting that
this problem is related to jitter, but can not resolve it. I've tried using
ulaw and ilbc with similar results. Both sites are configured to use IAX
trunking and both have X101P to provide clocking (on one end the X101P is in
red-alarm state as the line is not plugged in into X101P).
I am tempted to switch to SIP for interoffice communication but first I want
to try few more things..
Any suggestions?
Regards,
Wojtek