We have about 350 Polycom VVX-410 end points deployed at our office with a hosted VoIP vendor.
The biggest issue we have is with a simultaneous ring group of close to twenty  VVX-410 phones with presence enabled and a high call volume of about a call every two  seconds.
The net result is as the call volume rises so does the incident of on-way audio.
For background the purpose of this team is to offer our client's a 'real person' to answer their call and then get them to the right internal resource who can help.
Reviewing the Polycom docs and this community site I have found that this appears to be a 'known' issue:
Over the past two months we have worked with the VoIP vendor to troubleshoot the issue and our latest test involved using another hardware vendor's end points where the one-way audio did not show up even in extremely high call volumes.
So right now we are poised on a rip-out of all the VVX-410 phones with extension sidecars and replace them with the other vendor's end points.
It is my hope that since this is a 'known' issue that that it might have been addressed in a newer firmware than the one we currently are running [188.8.131.5222].
Thanks in advance for any suggestions or comments.
welcome to the Polycom Community.
The first document list's the recommended best practice and I would suggest to get your VoIP Vendor to open a support ticket with Polycom.
You should follow these recommendations or issues like you are experiencing would occur.
If this is some sort of an Internet discounter please post your phone's MAC address so I can look up who would be able to support you.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
I appreciate the recommended best practice but I believe we are under the number of extensions in the group but since the document is vague it does not really give any hard limits to guide us.
I will try to send you a PM because I believe the hosted VoIP vendor who also sold us the VVX-410s did contact Polycom support.