What does 10-9 mean in practice?

• A. Repeat the last transmission; ensure clarity.
• B. Proceed to the scene.
• C. Stand by for instructions.
• D. Code 4.

Answer: (A)

In radio communications, 10-9 is used to request a repeat of the last transmission because something about the previous message wasn’t heard clearly or understood. In practice, you’d say or think “ten-nine” to prompt the other person to repeat what they just said, ensuring you have the exact instructions or information (like a location, time, or action) before you proceed. This is crucial for accuracy and safety, especially in noisy or long-distance transmissions where details can get garbled.

The other phrases describe different states or actions and aren’t about asking for repetition. For example, moving toward a scene means you’re taking action, standing by for instructions means you’re awaiting orders, and a code indicating the scene is secure or under control signals a different status. So the option describing repeating the last transmission best captures the purpose of 10-9.