What is the signal for "Resume/All Clear"?

The signal for "Resume/All Clear" is indicated by 1 long blast followed by 1 short blast. This specific auditory signal is universally recognized in many contexts, especially in emergency and operational protocols, to communicate to personnel that it is safe to resume normal activities.

The long blast serves as a clear attention-getting signal, notifying individuals that a change in status is occurring, followed by the short blast which confirms that it is safe to proceed or that the situation has been resolved. This combination effectively communicates both the cessation of the previous alert and the start of normal operations, minimizing confusion among responders and ensuring quick and coordinated action.

In contrast, other options like 1 short blast for 5 seconds, 3 long blasts, or no sound do not conform to established signaling conventions for an "All Clear" or "Resume" command, thus they are not appropriate choices for indicating that conditions have stabilized and it is safe to return to normal functions.