Hi, The setup is like this: 3cx v8 on win7 12 extensions, mix of aastra and 2 models of polycom 2 ea. Patton 4 FXO running 5.x firmware, POTS lines. (config files via 3cx) There is a voice quality issue that I could use some help isolating, please. Extension to extension voice quality is good. Extension to voicemail, etc. is good. IOW, all is good internally. When a call is made to an outside number, the voice quality at the extension changes. When talking, the extension user gets some echo, and a lot of "scratchy" type noise, but only when talking. When listening to the outside caller, there is no noise. When neither party is talking, there is no noise. The external person never hears this echo or noise - it's only on the internal extensions. As all makes and models of phone exhibit the same behaviour, and as all internal calls are noise free, does this isolate the issue to the gateways/pots lines? Any ideas where I might start on this? I've made zero modifications to the patton configs generated by 3cx, as I wouldn't know which knobs to twist . Any assistance is greatly appreciated. Thanks, Les.