| 摘要 |
An electronic security system (10) includes an electronic lock device (12) and an associated electronic key (14). The electronic lock device includes a number of operational features, such as counters to monitor usage. The electronic key (14) also includes a number of operational features, such as packet-formatted audio download of key data using a piezoelectric transducer (150); codes that can be updated early without invalidating existing codes; and a tracking memory (148) that identifies the lock devices with which the key has communicated. When this tracking memory becomes full, operation of the key may be impaired. The impaired key can then only be re-enabled by downloading the tracking data from the key memory. The lock and key units cooperate to provide still additional operational features, such as a selectively-enabled, vandalism-resistant lockout list; a secure challenge-response security mechanism; and bilateral data/power exchange between the two units using just a single pair of conductors. |
