Concept
An emergency communication system (ECS) is any system (typically computer-based) that is organized for the primary purpose of supporting one-way and two-way communication of emergency information between both individuals and groups of individuals. These systems are commonly designed to convey information over multiple types of devices, from signal lights to text messaging to live, streaming video, forming a unified communication system intended to optimize communications during emergencies. Contrary to emergency notification systems, which generally deliver emergency information in one direction, emergency communication systems are typically capable of both initiating and receiving information between multiple parties. These systems are often made up of both input devices, sensors, and output/communication devices. Therefore, the origination of information can occur from a variety of sources and locations, from which the system will disseminate that information to one or more target audiences. An emergency notification system refers to a collection of methods that facilitate the one-way dissemination or broadcast of messages to one or many groups of people with the details of an occurring or pending emergency situation. Mass automated dialing services such as Cell Broadcast, Reverse 911, as well as common siren systems that are used to alert for tornadoes, tsunamis, air-raid, and other such incidents, are examples of emergency notification systems. Emergency communication systems often provide or integrate those same notification services but will also include two-way communication—typically to facilitate communications between emergency communications staff, affected people, and first responders. Another distinguishing attribute of the term "communication" may be that it implies the ability to provide detailed and meaningful information about an evolving emergency and actions that might be taken; whereas "notification" denotes a relatively more simplistic one-time conveyance of the existence and general nature of an emergency.