Abstract: One or more lock or key units of a secure entry system is equipped with a radio receiver. The receiver permits a memory in the lock or key unit to be updated with new data that is modulated onto a radio frequency signal. By this technique, system-wide changes of programming data, such as changes of lockout lists and access codes, and changes targeted to specific units, such as disabling a particular key, can be implemented simply and quickly.

Abstract: One or more lock or key units of a secure entry system is equipped with a radio receiver. The receiver permits a memory in the lock or key unit to be updated with new data that is modulated onto a radio frequency signal. By this technique, system-wide changes of programming data, such as changes of lockout lists and access codes, and changes targeted to specific units, such as disabling a particular key, can be implemented simply and quickly.

Abstract: An electronic lock system is disclosed in which a key can be assigned a limited lifetime, such as by storing data indicative of an expiration date in a key memory. Whenever the key is used with a lock, the lock first examines this key data and verifies that the key is still timely before performing any operations. After a key's expiration date has passed, it is useless until a new expiration date is stored in its memory. By this arrangement, keys that are lost or stolen soon lose their efficacy and no longer pose a threat to system security. The invention also permits the lock administrator to issue keys with different useful lives, so that, for example, a person who needs a key for only one day can be issued a key that expires the next day. A variety of other operational features are also disclosed.

Abstract: A key is provided with a memory in which, without user intervention, it collects data relating to lock operations each time the key interacts with a lock. This data is subsequently downloaded from the key to a computer. In some embodiments, the keys collect data relating not just to their own transactions, but also poll lock memories for the locks' prior transactions as well. By this arrangement, a patchwork collection of redundant data can be developed in the computer, improving data integrity and reducing data latency.

Abstract: An electronic lock system is provided with a "lockout list" that identifies keys that are to be prevented from opening system locks. Date coded lockout lists are carried in the memories of both the system's locks and keys. When a lock and key engage, the date codes of the lock and key lists are compared to determine which list is that most up-to-date. This list is then transferred into the other unit, overwirting that unit's stale list. Subsequent interactions of either of these units with other locks and keys will further spread the most timely lockout list data. By this arrangement, new lockout lists can be disseminated throughout a lock system simply by loading them into one or more keys. As these keys are used with locks, and those locks used with other keys, the list will spread throughout the system. A variety of other operational features are also disclosed.