SX20 one way video with VCS/VCS-E traversal

[rob.drye]

Calls to some of our registered SX10/SX20 endpoints (usually from Zoom, but not always) end up with one-way video.  The media paths shown in xstatus are address of the far-end system.  There does not seem to be any obvious  way to get our endpoints to use the VCS for the media path.  Other connections work without a hitch.  The setup on the VCS/VCS-E has been unchanged for a long time.

[Wayne DeNardi]

We'd need some more info on your systems and how they are configured to be able to provide any type of detailed guidance.

Where are the system registered?  SIP or H.323?  What is the call type, and how are the endpoints configured for CallSetup (Gatekeeper or Direct)?  How are you connecting with Zoom - but dialling out, or having Zoom dial in?  The more information you can provide us, the better we will be able to target any troubleshooting.