Currently experiencing the same problem with 9608 phones but with a PRI. Tried the same with echo cancellation. Tried different codecs, allow direct media path both on and off, different settings on the VCM. Replaced a few phones that users were complaining alot about. Voip assessment passed with flying colors. Nothing has seemed to help yet. No alarms in system status. Monitor traces dont show any packet loss, delay, jitter or anything else that would indicate poor quality. IP office is at R8.1.56 phones have the 6.2.2.09 firmware. Im convinced its a problem with the 9608's themselves. Thought about downgrading to an older firmware but have read about a lot of other issues with the older firmware on these phones. Going to be replacing a few phones with either 9620's or 1600 series to see if it changes anything.