Hi Abbas,

Do I need Cisco Unified Communications Manager?

In order to deliver a superior, simple user experience, Cisco Systems requires customers to deploy Cisco Unified Communications Manager with Cisco TelePresence. This, in conjunction with integration to enterprise groupware, provides one button to push simplicity for call launch, both for point-to-point and multipoint calls. Cisco Unified Communications Manager can function as a dedicated, video call manager within your organization.

From this good Q & A doc;

http://www.cisco.com/application/pdf/en/us/guest/products/ps7073/c1167/cdccont_0900aecd80544106.pdf

Hope this helps!

Rob