Here is a good Apache article worth taking the time to look at. It provides information and details on how to secure dynamic content on an Apache Web server. Topics covered include general security issues pertaining to dynamic content, securing Server Side Includes, configuring the Apache Common Gateway Interface, and wrappering dynamic content.
The U.S. Emergency Alert System allows radio and TV broadcasts to be interrupted for urgent emergency messages. Originally intended to allow the President to deliver nationwide messages in the event of war, it's mostly used on a state- or county-wide basis for weather alerts. The system is triggered by a digitally-encoded tone burst. The network is arranged in a star pattern, with 34 primary stations. Secondary stations use decoders tuned to the regular broadcasts of those stations, and so on down the line.