I believe you're referring to the requirement to start the Smart Card Service.
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/security/10_0_1/secugd/CUCM_BK_C68276B4_00_cucm-security-guide-100/CUCM_BK_C68276B4_00_cucm-security-guide-100_chapter_0100.html#CUCM_TK_S0EAA8E7_00