Does the UC500 support VOIP integration with non Cisco IP PBXes for site to site dialing?
The UC500 supports standards based SIP or H.323 trunks and in theory can interop with other PBXes (from vendors such as Nortel, Avaya, Alcatel, Siemens Samsung etc) if they support the same standards based trunks for site to site dialing. This does require customization using CLI (outside of CCA) and there has been no formal testing done with each vendor with the UC500.