Showing results for 
Search instead for 
Did you mean: 

No audio/video Polycom Group 500


I have vcs expressway in our dmz, vsc controller inside (X8.5.1), to mcu 5310 on 4.5(1.55).

External Polycom HDX calls work fine, but if they come in Polycom Group 500, we receive video but no audio, and there is no audio or video out to the external connection.

Polycom Group 500 calls internally to vcs controller or mcu have two-way video, audio from the mcu, but no audio from Polycom. 

Any pointers on this would be appreciated.



Chris Swinney


. However, in general, one way video/audio is "usually" down to firewall issues. However, the fact that you are receiving one media stream is a little more confusing. Oddly,, a colleague of mine came across a similar issue yesterday with a Polycom unit in China. As yet, they were unable to resolve the problem an I have been unable to look at it as yet.

What software revision is the Polycom on?




We don't have any Polycom Group Series in our environment as they can't be managed by TMS, but from previous experience with other Polycom endpoints (VSX/HDX), it's either a network issue (as suggested by Chris), or a Capset negotiation, Polycom software or configuration issue.

Some quick (non-network) things that spring to mind to check:

  • Make sure all your deivces are running up to date versions of the endpoint software.
  • Try to use the same protocol (H.323 or SIP) for the whole call path as much as possible.
  • Try turning call encryption on or off to see if that makes a difference
  • Check that the Polycom endpoint doesn't have "Basic Mode" enabled in Call Preference
  • Check that you're not limiting the Audio and Video codecs on your MCU

Otherwise, you'll need to start looking at your network (as mentioned by Chris, a better idea of your topology can help us to point you in the right direcction) as it's likely an issue caused by one of the devices between the endpoints.  If you have the time and skills, getting a Wireshark in between the devices can help greatly in seeing the traffic flow and signalling that may cause the one-way audio/video issue.

I'd also suggest that you post a similar thread over on the Polycom support communityas people over there are more likely to have a deeper insight in to how the Polycom devices operate.  Please feed back here any insight or solution you find from there (or a link to your thread) to help any others who may have a similar issue in the future.

Please remember to rate responses and to mark your question as answered if appropriate.

Please remember to rate responses and to mark your question as answered if appropriate.
Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: