AEMCA Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The code indicating that a message has been received and understood is "10-4." This code is part of the ten-codes or ten signals commonly used in communication, particularly among law enforcement and emergency service personnel.

When someone says "10-4," it serves as an affirmation that the information received has been acknowledged and comprehended. This kind of clear communication is crucial in high-stakes situations where misunderstandings can lead to significant issues.

The other codes mentioned have different meanings and are not used for acknowledging received messages. For instance, "10-3" typically relates to stopping transmission, "10-7" signifies that a unit is out of service, and "10-9" is used to repeat a message. Each of these codes serves a specific function in communication but does not convey the understanding of a previously received message as effectively as "10-4" does.