Plantronics + Polycom.
Now together as
I have an HDX 6000 HD serious polycom. When I connect to a remote site the people on the other end can see and hear my perfectly but I cannot see or hear them. Any advice would be great.
have a look at the Video FAQs here in the community. There is a good explanation about what to do firewall and NAT.
I think that is your problem. Open the right ports and forward them to your HDX.