Hello, We are preparing a new network and voip system for our customer. The 3CX v14 is hosted in www So far we have registered some Ubiquity UVP's, Gigaset N510, and Zoiper for windows. Unfortunately, the Polycom IP 6000 wont register. We have tried a lot of different settings. Iam starting to realize it just isn't compatible with a remote 3CX setup. In my opinion the SIP protocol isn't implemented like it should, but thats easy for me to say. I didn't try to use a SBC, but support of my voip operator thinks that it will not work with a SBC either. Asuming I can return it to my dealer, I am looking for a good (and working) alternative. Any suggestions ? Yhnx!