Which kind of Cisco TelePresence components are you talking about?
It might depend on your deployment and requirements.
In general the Cisco endpoints support standard based sip and h323.
The Cisco VCS is a great device to do connectivity towards 3rd party
infrastructure or register 3rd party devices to it.
Consider checking with your Cisco Partner, Cisco or external consultants
what the best option for you would be.
Please remember to rate helpful responses and identify helpful or correct answers.