We have an EX90 running TC7.3.3 it is registered to a VCS Control via H323 and to a CUCM via SIP. We have a conductor registered to our VCS Control along with a number of MCUs. The EX90 is configured for Multiway with a chosen protocol of H323.
We launch calls from the EX90 to two other endpoints also registered to the VCS Control via H323, but they are not registered to the CUCM via SIP, once the second call is established we hit the merge button on the EX90 but the merge fails. When we check the search history on the VCS Control we cannot see any request from the EX90 for the multiway. The multiway request appears to be routing to the CUCM via SIP, even though the chosen protocol for the multiway is H323.
What you're trying to do isn't supported, you can't register an endpoint to CUCM and VCS at the same time. CUCM normally and should disable H323 when an endpoint registers to it. If you want to use multiway, you should only register the EX90 to the VCS.
Actually you can register the device to CUCM and VCS at the same time, however, you need to disable the provisioning on the endpoint and configure it manually, otherwise, it will download the configuration from CUCM and will disable H323 service. However, as Patrick said, this is not a supported deployment. I do not suggest you to do so in a production environment.
If you decide to keep the double-registration, I suggest you to disable the provisioning on the endpoint and make sure that the Multipoint mode is set to "Multiway" with the proper multiway URI.
The best practice in your case is to deploy Conductor as a Media Resource of CUCM in order to provide Adhoc multipoint conferences.
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