Emergency override 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 == One of the earliest alerting systems developed specifically for cable television was implemented in the city of Alexandria, Louisiana in 1962 by Alpine Cable TV Co., a Louisiana-based cable television company.

Source: Wikipedia — Emergency override system (CC BY-SA 4.0)