All of our phone installs are in individual homes. Everyone within our company is using the exact same router (Netgear N600) and the exact same phone (Cisco SPA 525G). The biggest issue I'm having right now is the phone is able to call other 3CX extensions just fine, but if I try to call an outside line, I do not hear ringing and I never hear anything the other side has to say. They can hear me just fine. The phone appears to be setup properly. For instance, we have the 32 button attendant console attached and we can see when other extensions are on the line. The voice mail notification is working properly, etc. I believe everything we've done is proper -- could this be an open port issue? Thanks much!