The Cisco CallManager Admin service is not supported by IM and Presence Service and Cisco Unity Connection.
The Cisco CallManager Admin service supports Cisco Unified CM Administration, the web application/interface that you use to configure Cisco Cisco Unified Communications Manager settings. After the Cisco Cisco Unified Communications Manager installation, this service starts automatically and allows you to access the graphical user interface (GUI). If you stop this service, you cannot access the Cisco Unified CM Administration graphical user interface when you browse into that server.
The Cisco IM and Presence Admin service is not supported by Cisco Cisco Unified Communications Manager and Cisco Unity Connection.
The Cisco IM and Presence Admin service supports Cisco Unified CM IM and Presence Administration, the web application/interface that you use to configure IM and Presence Service settings. After the IM and Presence Service installation, this service starts automatically and allows you to access the GUI. If you stop this service, you cannot access the Cisco Unified CM IM and Presence Administration GUI when you browse into that server.