A container monitoring system which includes a microprocessor comprising a memory to store data, and a control program executed by said microprocessor, said microprocessor having a stand-by mode and an active mode, a communications means connected to said microprocessor for transmitting data from said microprocessor to a monitoring station, a zone monitoring device on the container connected to said microprocessor in a loop with said microprocessor in said stand-by mode, a power source for supplying power to said microprocessor, communications means and zone monitoring device, wherein upon said microprocessor receiving an input signal from said zone monitoring device, said control program directs said microprocessor to switch to active mode, generate and store in said memory an alarm message corresponding to said input signal from said zone monitoring device, activate said communications means, and transmit said alarm message to a monitoring station.