What does a flashing red light over the letter 'O' indicate?

A flashing red light over the letter 'O' indicates that one must stop and call for orders. This signal is typically used in operational contexts to convey that immediate action is required—specifically, a halt to current activities. The purpose of such a signal is to ensure that personnel do not proceed without clarification or further instructions, thus maintaining safety and efficiency in operations.

In environments such as construction sites or industrial settings, clear signals are crucial for communication and safety. For instance, the use of a flashing red light can be critical in situations where there may be potential hazards or changes in the work environment that necessitate careful management. By stopping and seeking orders, team members can coordinate effectively and ensure that everyone is aware of any new instructions or safety protocols.

This particular signal does not suggest merely preparing to change directions, warning of an upcoming stop, or proceeding with caution, as these actions may not address potential risks or miscommunications effectively. Therefore, while those actions may be relevant in different contexts, they do not encompass the urgency and specific requirement for immediate clarification that a flashing red light over the letter 'O' conveys.