Cannot connect a video call between a Polycom HDX 7000 and a LifeSize 220. They are in the same bldg and on the same network. If the LifeSize tries to call the Polycom it will not dial at all and then times out, if the Polycom tries to call the LifeSize it rings but will not answer.
Sounds like a network issue. Try to connect both devices to the same switch and check if the problem still exists.
Hope this could help.
In the release notes for a specific product release on Polycom video endpoints there is an interop table of what that release has been tested with, both Polycom products and our competitors. Without the software specifics it is hard to say if your configuration has been tested. But I agree, it is most likely a network thing, maybe a firewall between them not allowing videoconferencing to connect.