EAS serves as the nation's primary alerting system. It provides the President the capability to issue alerts and communicate to the public in response to emergencies. It was built on a structure conceived in the 1950s when over-the-air broadcasting was the best-available technology for widely disseminating emergency alerts. EAS has been upgraded numerous times since then, including in 2005 to include digital broadcast television as well as satellite radio and television. EAS was further expanded to include Internet-protocol-based television in 2007.