Configured this phone manually to 3CX. Registers fine, receives calls fine but gets fast busy when trying to make outbound calls. 3CX shows calls in logs and basically shows that it's rejecting the calls. In my opinion this is happening because 3CX and the IP 6000 are on different subnets. There is no NAT in the middle, they are just on different subnets. Yealink's work fine in this same network environment but the IP 6000 will not. We have had the same issue with Patton M-ATA hardware FYI and eventually gave up on the Patton ATAs. 3CX articles I have found state that many of the Polycom phones can't be used as remote extensions. In this case, they are not remote extensions, they are configured as local extensions but, they are on a different subnet. Is it possible to make this phone work with 3CX across subnets? If not, we will need to RMA this item as it was pretty expensive and we will need to replace with a conference phone that will be able to make outbound calls. Since we have Yealink VP-530's working fine at this location, in the same network environment across subnets, I am hoping that the Yealink conference phone would work, can anyone confirm this? I also have lots of T42 and T46's working in the same environment, across multiple subnets with other customers on the same 3CX multi-tenant instance. Only difference would be, I don't think I can auto-provision the Yealink conference phone with 3CX because it's not an in the drop down list. Any help is greatly appreciated.