What is the correct code for a safety check?

The correct code for a safety check is 10-4. This code is widely recognized in radio communication, particularly in law enforcement and emergency services, as a confirmation that a message has been received and understood. It indicates that operations can proceed safely, confirming that no additional action or response is necessary regarding the communicated status.

In many jurisdictions, the 10-4 code has become synonymous with a general acknowledgment, making it practical for safety checks where clarity and conciseness are essential. Thus, when conducting a safety check, using 10-4 allows personnel to quickly communicate that everything is in order without unnecessary elaboration.

The other codes listed serve different purposes within mobile communication protocols. For instance, 10-21 typically refers to making a phone call, 10-100 indicates a need to use the restroom, and 10-22 suggests an alert to disregard a previous message. Understanding the specific meanings of each code is crucial for effective communication, especially in high-pressure environments like those encountered in light rail operations.