BATTERY OPERATED ACCESS CONTROL CARD

An access control card for use in an access control system. A battery, a wireless signal sensor such as an antenna for receiving coded wireless signals such as coded radio frequency signals generated by a card reader, a clock connected to the battery and including a receiver are connected to the antenna for supplying a received signal based upon the coded radio frequency signal. A memory for stores first and second stored codes, and a transmit circuit connected to the antenna, to the clock and to the memory compares the first stored code to the received signal and transmits the second stored code when there is a match between the received signal and the first stored code.