A program called CTIManager includes the CTI components that interface with the applications that are separated out of Cisco CallManager. The CTIManager service communicates with Cisco CallManager by using the Cisco CallManager communication framework, System Distribution Layer (SDL). Installation of the CTIManager program occurs on the Cisco CallManager server during the Cisco CallManager installation. You can have one or more CTIManagers active in a cluster, but only one CTIManager can exist on an individual server. An application (JTAPI/TAPI) can have simultaneous connections to multiple CTIManagers; however, an application can use only one connection at a time to open a device with media termination.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/5_0_1/ccmsys/a08cti.html
