What does the 10-4 acknowledgement indicate?

What does the 10-4 acknowledgement indicate?

• A. The message was received and understood.
• B. Request for backup.
• C. End of transmission.
• D. Switch channel.

Answer: (A)

10-4 is the acknowledgment that a transmission was received and understood. It means the listener heard the message clearly and grasps what’s being asked or directed, signaling readiness to act as needed. It’s not a request for backup, not the end of transmission, and not a switch to another channel—those would be indicated by other codes. In practice, saying 10-4 is like saying “copy that” or “roger—that was received and understood.”

10-4 is the acknowledgment that a transmission was received and understood. It means the listener heard the message clearly and grasps what’s being asked or directed, signaling readiness to act as needed. It’s not a request for backup, not the end of transmission, and not a switch to another channel—those would be indicated by other codes. In practice, saying 10-4 is like saying “copy that” or “roger—that was received and understood.”