Hello GeorgeN,
welcome to the Polycom Community.
I do not believe we currently support RFC3581 as I could not find this in our Admin Guide or internal documentation.
The next step would now be to work with your Polycom reseller as described in the VoIP FAQ here:
Jan 03, 2013 Question: How can I request a change to the current Polycom SIP / UCS Software?
Resolution: Please check => here <=
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services
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The title Poly Employee & Community Manager is a community setting and
does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.
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Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
