What does a continuous tone in a radio signal typically indicate?

A continuous tone in a radio signal is a critical feature that serves as a clear indicator of urgency. Specifically, it typically signifies a distress call. In maritime communication, a continuous tone is often employed to alert all stations that there is an emergency situation requiring immediate attention. This type of signal is designed to cut through routine traffic and automatically draw the attention of listeners, prompting them to switch to the appropriate channels to provide assistance or receive important information regarding the emergency.

Routine communications and general broadcasts do not utilize continuous tones. Instead, they typically consist of voice transmissions or other forms of signaling that do not signal urgency. An emergency warning may sometimes be conveyed through other types of alerts or alarm signals, but a continuous tone is particularly associated with distress to ensure that it stands out in the busy radio spectrum. Understanding these distinctions is essential for responding effectively during maritime emergencies.