Cadena nacional
In several Latin American countries, a cadena nacional (Spanish for 'national network'; plural cadenas nacionales), also referred to as a cadena oficial (Spanish for 'official network') or red voluntaria (Spanish for 'voluntary network'), is a joint broadcast, over various media (usually radio and television), directed at the general population of a state. Initially conceived as a form of emergency population warning, these broadcasts are often of a political nature, as most of them are messages by governmental authorities about various topics of general interest.