Which two services must be activated on CUCM for phone registration?

• A. Cisco TFTP
• B. Cisco CallManager
• C. Cisco TFTP and Cisco CallManager
• D. Cisco TFTP and Cisco Unity

Answer: (C)

Phones register in CUCM only when two services are up and reachable: the TFTP service and the CallManager service. The TFTP server provides the phone with its startup configuration and firmware, which the phone downloads during boot. Without TFTP, the phone cannot obtain its config and cannot boot properly. After it has its configuration, the phone contacts the CallManager service to register and participate in call processing. If CallManager isn’t running or reachable, the phone can load its settings but cannot register or place calls. Voicemail services like Unity aren’t required for registration and handle different functions. So both TFTP and CallManager must be activated for phone registration.