AEMCA Practice Exam

What is the meaning of the code 10-4?

1. Busy

2. Received message

3. Out of service

4. Repeat

The correct answer is: Received message

The code 10-4 is commonly used in radio communication to signify that a message has been received and understood. This code is part of a standardized set of communication codes known as "10 codes," which were originally developed for law enforcement and other emergency services to facilitate clear and concise communication. Using 10-4 helps to reduce misunderstandings during critical communications, especially in noisy environments or when the clarity of voice transmission may be compromised. When someone uses 10-4, it indicates acknowledgment, ensuring that the message sender knows their communication has been successfully received and understood. In contrast, other codes such as "busy," "out of service," and "repeat" convey different statuses or requests that do not directly indicate acknowledgment of a message. Therefore, when looking for the meaning of 10-4, it's clear that it pertains specifically to the confirmation of receiving a message.