METHOD AND APPARATUS FOR TRACKING AND MONITORING CONTAINERS

A tag has a circuit portion that functions as a reader capable of wireless communication with other tags. According to a different aspect, a tag has a circuit portion with first and second modes, the circuitry consuming less power in the second mode than the first mode, and exiting the second mode only in response to an act by a human. According to yet another aspect, a tag can receive wireless communications conforming to one of a cellular telephone network communication protocol, a satellite communication protocol, and a wireless computer network communication protocol. The tag responds to receipt of a predetermined wireless signal conforming to the one protocol by carrying out one of first action that includes causing the tag to enter an electronically secure state, or a second action that includes causing the tag to exit the electronically secure state.