asterisk users - May 2004 - Sound Distortion using IAX?

Hi All,

At present calls over IAX2 (ilbc) are good but they suffer from
occasional distortion. The strange thing is that the distortion
can only be heard by the calling party and not the called
party in 95% of cases. 

IAX2 is being used with trunking enabled, using the ztdummy
module as a timing source. Bandwidth shouldn't be an issue
as there is more than sufficient plus we use QoS (internally).
For the record the asterisk box is running the latest version
from cvs-head.

Anyone got any suggestions?

Does jitterbuffer work in cvs-head? Its currently disabled
and I wondered if it would have any positive effect on call
quality?

Regards,
Nathan.