Emergency override system

Not to be confused with the Emergency Alert System or Emergency Broadcast System.

Emergency override system

Screen displayed for emergency override system activation in St. Joseph, Missouri, c. 1990s
Type	Emergency warning system
Country	United States
Replaced by	Emergency Alert System

An emergency override system (also known as cable override or emergency alert system, among other terms) is a system designed to warn subscribers of cable television broadcast feeds of threats such as severe weather and other civil emergencies.

History

Digital Alert Systems, which was once a subsidiary company of Monroe Electronics before 2018, claims that Monroe Electronics developed the first emergency override system in the late 1960s. ^[1]

With most cable systems transitioned to digital cable by the mid to late 2010s, the emergency override has been replaced largely with the Emergency Alert System which employs Specific Area Message Encoding technology to activate for potential disasters and deactivate to resume cable broadcasts, especially late at night when many public servants aren't available to break in.^{[ citation needed ]}

Operational details

The activation of an emergency override system is initiated, typically by local law enforcement or other emergency management staff, by dialing a number and entering a PIN through a designated telephone. Once correctly entered, programming on all channels for cable subscribers in the area is interrupted. The extent of how programming is affected varies from system to system, with some merely overriding the audio feed while others additionally remove the video feed and may replace it with static or a generated slide. The operator then delivers a live, spoken message informing viewers of the nature of the override, including giving any advised actions for emergencies, before they dial out to end the override. ^[2]

Emergency override systems could also be activated by other entities. For example, in 1997, Union Pacific developed in coordination with the Roseville Fire Department a local warning system that was intended to warn neighborhoods in Roseville, California near railroads, of hazardous waste spills. ^[3] Union Pacific would warn the Roseville Fire Department of a spillage, and, if the incident was severe enough, part of this local warning system would interrupt cable television with a blue screen and a taped message providing warning of an incident and evacuation. ^[3]

System tests

Emergency override systems are typically tested once weekly at randomly selected times, as well as scheduled monthly tests and yearly tornado drills. ^[4]

References

1. "About us". Digital Alert Systems. Retrieved October 29, 2025.
2. Kirk, Bill Van (March 14, 1981). "Troy police hook up TV hotline". Troy Daily News. p. 1. Retrieved October 29, 2025– via Newspapers.com.
3. "Roseville Hazardous Materials Warning System - Roseville California". The Press-Tribune. 1997-04-08. p. 3. Retrieved 2025-11-18.
4. "Cable TV alert system will be tested this week". The Journal-Press. October 13, 1981. p. 2. Retrieved October 29, 2025– via Newspapers.com.