Communications

A high chirp in and a lower chirp out, twice, the tones that bracket each message in space missions and military radio.

Rising beeps, a burst of static and a click as the line opens, the moment two sides finally connect on a mission or a rescue call.

A sharp burst of noise cut by a click, twice, the end of a radio call for police, pilots, security teams or a squad.

A fast screech of digital warble, for coded messages, a satellite uplink, a hacker sending files or alien signals.

A carrier tone breaking into dropouts and a flat tone, the sound of contact cut off with a crew, a drone or a probe.

A bright two-tone chime three times, for a console calling for attention, a ship hail or a dispatch desk lighting up.