If you don't know: The Emergency Alert System (EAS) is a warning system in the United States that interrupts TV and radio programming in order to provide important information on events that pose danger to your life. This cartridge replicates the intimidating tones from the system using the secret PCM channel in PICO-8.
Note that the National Periodic Test here is completely fake. There's no voice announcement included for now, due to concerns about hitting the limited storage capacity of PICO-8 carts.
WARNING: Never broadcast the EAS header bursts on TV or radio! The FCC will have the right to fine anyone for such misuse of EAS/SAME tones.