Hello, We are evaluating the 3CX and we note fluctuating voice quality while using 3CXPhone. The PBX is in our private cloud, behind a firewall. We have two desktops, powerful enough, at two distant locations. Both locations have a decent VDSL internet line, the cloud has enough bandwith. Both softphones are connected with the cloud through a VPN. Both 3CXPhones have the same configuration and both extensions also. We use at both sides the same Logitech headset. In order of preference, we've set the codec list G.722, PCMU, PCMA and GSM. The pbx is configured to send audio. No matter if user A calls user B or if user B calls user A, the problem is the same. The caller ( A or B ) has a constant good sound quality. The receiver ( B or A ) has a fluctuing sound quality during the same call, sometimes good, sometimes less, without any visible reason. Any idea ? Best regards. Michel.