The only requirement for the use of CC is to configure an agent for the caller and a monitor for at least one recipient of the call. This is controlled using the cc_agent_policy for the caller and the cc_monitor_policy for the recipient. For more information about these configuration settings, see configs/samples/ccss.conf.sample. If the agent for the caller is set to something other than "never" and at least one recipient has his monitor set to something other than "never," then CC will be offered to the caller at the end of the call.
Once the initial call has been hung up, the configured cc_offer_timer for the caller will be started. If the caller wishes to request CC for the previous call, he must do so before the timer expires.