Wireless communications circuit

摘要

A portable motion-sensing circuit (128), carried by a user, indicates that motion is sensed in response to detecting whether the user has been moving for a predetermined period of time. A communication circuit (120) operates in active mode and inactive modes respectively consuming higher and lower power, permits or inhibits access authentication communications in the active and inactive modes, and operates in the active mode in response to the motion being sensed at the motion-sensing circuit (128).