Emergency Communication Guide

SOS — Universal distress signal

SOS is the best-known Morse signal: ··· ——— ··· (three dots, three dashes, three dots). It is recognized worldwide. Use it when you need to attract attention in an emergency.

You can send SOS by sound (whistle, horn, knocking), light (flashlight, mirror), or radio. Repeat the pattern with short pauses between groups.

Morse and Audio — Try our Morse and Audio tool to hear and see SOS, then copy and repeat the pattern with sound or light.

When to use Morse in emergencies

• No cell coverage or power: use light or sound in Morse.
• Maritime or aviation: radio Morse (e.g. 500 kHz) or flashing light.
• Trapped or unable to speak: tap or blink SOS on a surface or with a light.
• Outdoor rescue: use a mirror or flashlight to flash SOS toward aircraft or distant observers.

Sending SOS effectively

• Keep the rhythm clear: three short, three long, three short, with a distinct pause after each full SOS.
• Repeat every 1–2 minutes so rescuers can locate the direction.
• If using light, avoid pointing directly at aircraft cockpits; aim slightly off to avoid glare.

Text and Morse · Morse Code Chart — For conversion and practice, use our Text and Morse tool and Morse Code Chart.