Abstract: A door access system synchronizes a secure-side controller relay with a local access decision at a reader without relying on a packet-network round trip. The reader stores credential data, performs on-device authentication, selects a door state—OPEN_PULSE, HOLD_OPEN, or RETURN_TO_SECURE—and emits a reserved state token over a lightweight hard-wired link. The controller decodes the token and drives its relay per a shared state machine with timing, refresh, precedence, and watchdog rules so the actuator mirrors the reader. Events and optional images or video are sent over IP when available; if the network is unavailable, the reader continues to grant access using locally stored credentials and caches events for later upload. Credential and policy updates are delivered to the reader from a remote service independently of the hard-wired link. In some embodiments the controller lacks any packet-network interface.