What does Signal 19 indicate in communication protocols?

Signal 19 in communication protocols is specifically associated with a relay by phone. This designation is utilized by law enforcement and emergency response agencies to facilitate clear and effective communication, ensuring that all personnel understand the context of the message. A relay by phone indicates that information needs to be communicated directly via a telephone call rather than over the radio, which can be crucial for transmitting sensitive information or details that require privacy or clarity.

This coded communication helps streamline operations and avoid confusion, particularly in high-pressure situations where time and accuracy are vital. Recognizing Signal 19 allows officers to quickly assess the type of communication required and respond accordingly.