I cant tell anything on the Polycom systems, but its two parts, its the audio and video codecs which are used.
In these multipoint or live meeting calls it seems to be RTAudio and RTVideo.
These are supported for example with the Advanced Media Gateway as well.
But besides the point to point calls (which work fine with the VCS itself, especially with the VCS X7 B2BUA)
I cant say if there is any vendor besides Microsoft supporting the internal Lync multiparty way.
I think its using some proprietary XML SIP extension.
Anyhow you could have a Cisco / Codian MCU connected to the VCS and host a multiparty meeting
with Cisco, Lync and 3rd party participants there. This would also give you continuous presence
and not only switching like on Lync.
Further let me quote from:
http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/config_guide/Cisco_VCS_Microsoft_OCS_2007_R2_and_Lync_2010_Deployment_Guide_X7-0.pdf
"Joining a MOC/Lync conference (AV MCU)
Using a MOC/Lync client to invite a third party to join the call does not work if the third endpoint is an endpoint registered to the Cisco VCS Control, or if the endpoint registered to the Cisco VCS Control is already in the call and another MOC/Lync client is introduced into the call.
This is because when the MOC/Lync client invites a third party to join a call, the MOC/Lync client tries to create a conference using Microsoft proprietary messaging (xml in SIP messages), and this is not supported by standards-based video endpoints.
Neither Cisco VCS Control nor standards-based video endpoints support the Microsoft proprietary signaling.
Note, however use of Multiwa"y on endpoints can join MOC/Lync clients into an ad hoc conference (see Cisco VCS Multiway deployment guide)."
To answer your question, not on the hosted Lync conference, but you could use a Cisco MCU.
Martin
please vote the replies and set your message to answered if it is.
