Hello PACT,
welcome to the Polycom Community.
The VVX phones in comparison with the CX phones have far more sophisticated method's of discovering VLAN's as an example using CDP,LLDP or even DHCP so you may not be able to compare them side by side.
Polycom and other manufacturers produce these optimized for Microsoft® Lync® devices after a reference design and the embedded OS running on the phones is provided, supported and maintained by our partner Microsoft®.
You therefore may want to reach out to the Microsoft® community and / or Microsoft® support directly instead as this is the most direct and efficient path.
Please try here
Alternatively your Polycom reseller who sold you the CX phone is your Tier 1 contact and can raise a Support ticket with Polycom for you if the unit is in warranty. If outside warranty there are other options as pay per incident.
Failing all the above you may want to work with your network team and setup a spanned port and simply compare the network traffic between the CX phone and the VVX phone.
Best Regards
Steffen Baier
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The title Polycom 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. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.
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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
