Hi all, I hope someone can give me guidance on my issue and fix this once and for all. I am on Elastix 1.6-10 and using Polycom IP550 handsets with default sip.cfg (version 3.2.2) from Polycom, not the sip.cfg generated by Elastix. *Edited* I am using the OSLEC as the echo cancellation for DAHDI. My PBX network layout: Polycom IP550 <--CAT5--> Switch <--> Elastix <--> PRI circuit When they make a call outside over the PRI, they hear echo (they hear their own voice back) on external calls. Again, it doesn't happen all the time, but enough to bug them. From internal extension to extension, no problem with echo. I know this is like beating a dead horse, but I can't figure this out or even know where to start. Thanks!