Cisco Unified Communications Manager SIP integration with Cisco Unity Connection requires which configuration component to connect to voicemail?

A Route Pattern in Cisco UCM is configured with the voicemail pilot number and points to a SIP Trunk destined for Cisco Unity Connection. This pattern intercepts calls to voicemail (e.g., forward-to-voicemail calls) and routes them through the SIP Trunk to CUC. Without the Route Pattern, UCM has no mechanism to direct calls to the Unity Connection SIP interface.

A Hunt Group distributes incoming calls among a set of lines or devices and has no role in routing calls to an external voicemail system.

A Route Group is a collection of gateways or trunks used within a Route List for call routing decisions, not a standalone component that connects UCM to voicemail.

A Hunt Pilot is the directory number that triggers a Hunt Group and is unrelated to SIP voicemail integration configuration.

Trunk Group is not a standard Cisco UCM configuration object used in voicemail SIP integration; the relevant trunk object is a SIP Trunk, not a Trunk Group.