NATIONWIDE SYSTEM FOR SELECTIVELY DISTRIBUTING INFORMATION

摘要

A national warning system utilizes three geographically spaced national warning centers (one primary, two alternates) for controlling and commanding 10 geographically spaced distribution centers which are responsible for transmitting radio signals throughout ten respective regions of the country. Depending upon the command sent from the active warning center, one or more distribution centers are programmed to transmit an appropriate demuting code and message. The demuting code activates one or more groups of receivers; the message may be voice, teletype, siren actuation, etc. Command transmission from the active warning center to the distribution center can be via radio link or wireline depending on the system operating mode and the transmission path selected by the warning center operator. An overall monitoring sub-system permits automatic confirmation of reception of commands and allows the operating status of all transmitters to be known at the warning center.