In which two scenarios would a caller who is calling into the Cisco Unity Connection general pilot number hear the opening greeting of the voice-mail system and be prompted for a user ID and PIN?…

A non-subscriber has no mailbox in Cisco Unity Connection, so the system cannot match the caller to any account and must play the opening greeting and request a user ID and PIN for identification.

A subscriber who sends a calling number is automatically identified via caller ID and is taken directly to their mailbox PIN prompt without hearing the full opening greeting flow.

A subscriber who does not transmit a calling number cannot be auto-identified via caller ID, so the system treats the call identically to an unrecognized caller and prompts for a user ID and PIN.

SIP phone users are not unconditionally prompted; identification behavior depends on whether the system receives a recognized calling number, not on the signaling protocol used.

SCCP phone users are also not unconditionally prompted; the same calling-number identification logic applies regardless of whether the endpoint uses SCCP or SIP.

The scenario is entirely valid and describes standard Cisco Unity Connection call-flow behavior for callers who cannot be identified by the system.